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Biomedical subjects

M Franco

Publications and source records attributed to M Franco.

At least 253 records · Page 14Linked to original sources

Inhibition of metastases by a serum factor associated to concomitant resistance induced by unrelated murine tumors.

Murine lung metatases growing undisturbed by the primary tumor were significantly inhibited by the concomitant resistance induced by a secondary subcutaneous implant of two unrelated tumors. Such inhibition was T-independent since it was also observed in nude mice; its full expression was dependent on the presence of the secondary tumor implant and it was exerted on both macroscopic and microscopic established metastases and not on the process of tumor cell dissemination from the primary tumor. Direct and indirect mechanisms seemed to be involved, the former affecting the metastatic cells per se by causing a decrease in proliferation and an increase in apoptosis while the latter affected neo-vascularization. These antitumor and antiangiogenic effects could be attributed to a serum factor induced by the unrelated tumors generating concomitant resistance. This factor proved to be heat, acid and alkaline resistant and dialysable; it was recovered in an HPLC column with maximum absorption at 215 and 266 nm; it was anionic at neutral pH, exhibiting free carboxil groups and one or more molecules of tyrosine, with a molecular weight between 870 and 1300 Dalton. Intravenous administration of this factor significantly inhibited lung metastases, decreasing mitosis and increasing apoptosis similar to that observed in the presence of the unrelated tumors.

Animals↗

Two different types of concomitant resistance induced by murine tumors: morphological aspects and intrinsic mechanisms.

Concomitant resistance (CR) is the phenomenon according to which a tumor-bearing host inhibits the growth of a secondary implant of the same tumor at a distant site. Confirming and extending previous results of our laboratory, histological studies have revealed that two temporally separate peaks of CR can be detected throughout tumor evolution. The first peak induced by immunogenic small tumors, in euthymic but not in nude mice, is associated with extensive necrosis of the secondary tumor implant and a profuse infiltration of polymorphonuclear granulocytes and mononuclear cells resulting in its final destruction; these features correspond to a typical immunological rejection. The second peak of CR induced by both immunogenic and non-immunogenic large tumors, in euthymic as well as in nude mice, is characterized by a dormant tumor stage with scarce or null mononuclear infiltration, associated with a significant reduction of tumor mitotic index and of the number of PCNA+ cells along with an increase in apoptosis and an arrest in S phase. In previous reports we suggested that a 1000 D serum fraction from mice bearing large tumors could be responsible for the induction of this dormant tumor stage. In this study tumor cells incubated in vitro with that serum factor mimicked the inhibition and cellular alterations observed in vivo in the secondary tumor inhibited by the second peak of CR. Moreover, the passive transfer of this factor by the intra-peritoneal (i.p.) route induced an in vivo inhibition of an i.p. tumor reproducing the image characteristic of the second peak of CR. This represents a direct proof that this serum factor can restrain tumor growth in vivo and that it is, most probably, the effector of the second peak of CR.

Animals↗

[Sexual dysfunction with antidepressive agents. Effect of the change to amineptine in patients with sexual dysfunction secondary to SSRI].

UNLABELLED: Sexual dysfunction secondary to the use of antidepressants, especially clomipramine or SSRI's is an adverse effect that is often underestimated and according to earlier studies, this can affect approximately 60% of the patients. This presents as a decrease in libido, alterations in the ability to reach orgasm/ejaculation, and an erectile dysfunction or a decreased vaginal lubrication. This dysfunction appears to be related with the resulting increase in serotonin and with the stimulation of serotonin 5HT2 receptors. OBJECTIVES: 1) Evaluate the effect of amineptine, a drug with an increased dopamine transmission and scant serotonin transmission, on the sexual function of depressed patients who begin treatment, and 2) evaluate whether the change to amineptine improves the sexual function in patients who presented sexual dysfunction after beginning treatment with a SSRI. MATERIAL AND METHODS: Prospective, observational, open and multicentric design. 111 patients with an average age of 41.3 years (36 men, 75 women) were distributed into three groups: Group 1 (n= 26): patients with depression (DSM IV) who begin de novo treatment with amineptine 200 mg/day. Group 2 (n= 47): depressed patients undergoing treatment with a SSRI who show a favorable response and who present sexual dysfunction secondary to a poorly tolerated treatment, so the treatment is changed to 200 mg/day of amineptine. Group 3 (n= 38): patients with the same characteristics as those of group 2, but whose treatment was changed to 20 mg/day of paroxetine. The < > (Montejo et al, 1996) was used together with the Hamilton Depression Scale, the IGC Scale, and an adverse events scale, over a 6 months follow up period during which visits took place at: baseline, month 1, month 2, month 3, and month 6. RESULTS: In group 1, treated with amineptine from the beginning, of the 5 patients who showed a decrease in the libido at the beginning of the treatment, only one still presented this in the 6th month. The Hamilton Scale decreased from 23.12 (baseline) to 5.25 after 6 months. After substituting amineptine for SSRI's in patients with sexual dysfunction, the incidence of any type of sexual dysfunction decreased significantly from 100% (baseline) to 55.3% after 6 months. (P< 0.001). The incidence of delayed orgasm dropped to 15.8%, anorgasmia to 17.4%, and impotence dropped to 15.8% in this group, with the antidepressant effect that had already been achieved with the SSRI being maintained. However, in group 3 there was barely any improvement on the sexual function after changing to paroxetine (20 mg/day), with the baseline incidence being 100% and the incidence after 6 months being 89.7%. In this last group the antidepressant effect present at the baseline level, was maintained. CONCLUSIONS: Amineptine was shown to be an effective antidepressant in the patients studied, and did not cause secondary sexual dysfunction, and even improved the dysfunction that was present in some patients. In those patients previously treated with SSRI's, amineptine is able to significantly improve the sexual dysfunction and yet maintain the efficacy of the antidepressive treatment used before these 6 months. On the other hand, Paroxetine did not improve the sexual dysfunction of the people in whom this drug substituted another SSRI, as this is an adverse effect common to the entire group of selective serotonin re-uptake inhibiting drugs. Amineptine showed a good safety and tolerance profile. Its most common side effect (anxiety/restlessness) disappeared 2 months after the beginning of the treatment.

Adult↗

A simple procedure for determining the presence and concentration of Listeria monocytogenes in dairy products.

This paper presents a simple method for determining both the presence and concentration of Listeria monocytogenes in dairy products. The method involves application of the Most Probable Number (MPN) technique and enrichment of a 25 g sample. Our tests showed that the MPN correlates with the Colony Forming Units (CFU), and estimated concentrations of as low as 1 bacterium/gr or less. We also studied the influence of Listeria innocua as an accompanying flora. We detected L. monocytogenes, even in the presence of concentrations of 4 times as much L. innocua. Nonetheless, L. monocytogenes could not be detected when the concentration of L. innocua surpassed 90%.

Animals↗

[Listeria monocytogenes endocarditis in a patient with mitral prosthesis, left auricular thrombus and adenocarcinoma of the colon].

A case of Listeria monocytogenes endocarditis in a patient with mitral prosthetic valve, left atrial thrombus and colonic adenocarcinoma is reported. Vegetations were not demonstrated by transesophageal echocardiography and the clinical course was benign and without complications. Cure was achieved with antibiotic therapy, and surgery was not required. These features suggest that atrial thrombus could be the source of infection.

Adenocarcinoma↗

[A change in glomerular permeability in renovascular hypertension. Participation of angiotensin and structural lesions].

To characterize the decrease in glomerular permeability that occurs in contralateral kidney of renovascular hypertension, glomerular hemodynamics were studied in Goldblatt hypertensive and normotensive control rats. The effects of converting enzyme inhibition (captopril) and renal vasodilatation induced with hyperoncotic plasma were evaluated: in addition, glomerular morphometry was performed. In hypertension, glomerular capillary pressure was increased, ultrafiltration coefficient was decreased, single-nephron filtration rate was normal and afferent resistance was elevated. Captopril rose glomerular filtration rate only in normotensive rats, but ultrafiltration coefficient increased in both groups. Hyperoncotic plasma induced a 98% increment in filtration rate and ultrafiltration coefficient rose by 48% in normotensive group. In hypertensive rats, filtration rate increased only 15% and ultrafiltration coefficient diminished 6%, morphometric studies showed dilatation of capillary loops and a larger glomerular volume. Similar response to captopril in both groups of rats suggest that the reduction in ultrafiltration coefficient in hypertension is not dependent of angiotensin; lack of response to hyperoncotic plasma suggests that it could be produced by structural changes in capillary wall that diminish hydraulic permeability since the larger glomerular volume indicates a greater area for filtration.

Angiotensin II↗