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Biomedical subjects

D Segre

Publications and source records attributed to D Segre.

71 records · Page 4Linked to original sources
PubMed1967

Altered response to pneumococcal polysaccharide in offspring of immunologically paralyzed mice.

The dose of pneumococcal polysaccharide type III required to induce immunologic paralysis in newborn offspring of immunologically paralyzed mice was one-tenth of the corresponding paralyzing dose for newborn offspring of normal mice. Similarly, immunization of the offsprinig of the paralyzed mice was accomplished with one-tenth the dose of polysaccharide necessary to immunize normal newborn mice. The altered susceptibility of newborn mice from paralyzed mothers to the induction of both paralysis and immunity was predicted from theories of antibody formation which postulate that the induction of tolerance or immunity is controlled by the concentration of natural antibodies specific for the antigen used.

Animals↗
PubMedDate not supplied

Age-related changes in B and T lymphocytes and decline of humoral immune responsiveness in aged mice.

The activity of the immune system declines in an age-related fashion, after reaching a peak in young-adult animals. Although this pattern has been well documented, the mechanisms responsible for the decline of immune potential in senescence have not been fully elucidated. At the same time, it has become apparent that the immune response depends on complex interactions among different cell types. We review the results of the analyses of B- and T-lymphocyte function and activity in the humoral responsiveness of aged mice that have been performed in a number of laboratories, with a variety of experimental techniques. We conclude that an increase in T-cell suppressor function is the first immunologic lesion of aging in mice. This is followed by a decrease in T-cell helper function and finally by a loss of B-cell function.

Aging↗
PubMedDate not supplied

Modulation of the host's immune response to Plasmodium berghei by a parasite-derived immunosuppressive factor.

It is well known that Plasmodium-infected hosts are immunosuppressed, as show by their depressed immune responsiveness to a variety of antigens. It is not known, however, whether the immune response of malaria-infected animals to the malarial parasite itself is suppressed. The availability of a noninfectious, immunosuppressive factor (ISF) derived from Plasmodium berghei-infected rat erythrocytes made it possible to investigate this question. Mice infected with P. berghei and injected with the ISF had higher levels of parasitemia and shorter survival times than control mice that were similarly infected but were treated with control material derived from noninfected rat erythrocytes or with saline solution. Conversely, mice immunized against the ISF and then infected with P. berghei had lower parasitemias and longer survival times than mice immunized with the control material or with saline solution. We conclude that immunosuppression in murine malaria affects the course of malaria infection.

Animals↗
PubMedDate not supplied

[The role of portography with computed tomography in the diagnosis of liver metastases from colorectal neoplasms].

This study was performed to confirm the high sensitivity of CT during arterial portography (CTAP) versus US and dynamic CT in the diagnosis of liver metastases from colorectal cancer. Ninety patients with 108 colorectal cancers underwent US, dynamic CT and CTAP to investigate the presence of liver metastases. US depicted 39 metastases in 26 patients, dynamic CT 46 metastases in 29 patients and CTAP 54 lesions in 34 patients. CTAP detected 8 metastases missed at dynamic CT; 4 of them were < 1 cm in diameter, 3 ranged 1-2 cm and one metastasis > 2 cm in diameter. After preoperative investigations only 7 patients were considered for hepatic resection. At surgery, palpation and intraoperative US of the liver detected two more metastases in the same patients. Our experience, in agreement with recent studies, confirms CTAP as the most sensitive preoperative method in detecting liver metastases and its superiority to be most apparent in lesions < 1 cm in diameter. Therefore, we consider CTAP an essential imaging technique for planning the correct treatment of liver metastases.

Adult↗
PubMedDate not supplied

[Etiopathogenesis and physiopathology of hemorrhoidal disease].

Many possible causes have been proposed to explain the pathogenesis of symptomatic hemorrhoids: constipation and abnormal bowel habits are commonly blamed despite largely contrary evidence. The most consistently demonstrated physiological abnormality is an increased maximum resting anal pressure. The pathophysiologic theory, made popular by Thomson's studies, in which the anal cushions break their elastic support and become more sensitive to the increase of pressure from straining and to trauma from hard stool, with a progressive downward displacement, is currently the best accepted. The intimate mechanism of functioning and control of the arteriovenous anastomoses remains unclear as does the existence of an individual susceptibility in which a part is played by socioeconomic, cultural and psychological factors.

Hemorrhoids↗