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Biomedical subjects

A Lanfranchi

Publications and source records attributed to A Lanfranchi.

At least 55 records · Page 3Linked to original sources
PubMed1989

Alterations of in vitro interleukin 1 and 2 in diabetic children.

We studied interleukin 1 (IL-1) and interleukin 2 (IL-2) production in unstimulated and stimulated cultures from 27 young diabetic patients and 21 age-matched healthy subjects. In unstimulated cultures monocytes from newly diagnosed patients produced significantly higher levels of IL-1 than controls. In lipopolysaccharide (LPS)-stimulated cultures, IL-1 production in patients with fresh and long-standing diabetes was no different from that of controls. IL-2 production was low or absent in unstimulated cultures from insulin-dependent diabetes mellitus (IDDM) patients and controls. In phytohaemagglutinin (PHA)-stimulated cultures both patient groups produced significantly less IL-2 than controls. No correlation was observed between IL-1, IL-2 production and HbA1 levels or the presence of HLA-DR3 or DR4. Our data on "spontaneous" IL-1 production support the hypothesis that monocytes from some newly diagnosed IDDM patients may circulate in a "preactivated" state. The low levels of IL-2 might be explained by an abnormal consumption or by the presence of increased soluble IL-2 receptor levels or by a serum factor which interferes with IL-2 production. Alternatively, it may be a genetically determined trait.

Adolescent↗
PubMed1988

Cell-mediated cytotoxicity in children during and after therapy for acute lymphoblastic leukemia.

Cell-mediated cytotoxicity is considered to play a major role in immune defense and in particular in the killing of virus-infected and neoplastic cells. It appears to have some interesting implications when considering the infectious risk of acute lymphoblastic leukemia (ALL) children during immunosuppressive chemotherapy and the role of self-defense against minimal residual disease. We have studied natural killer (NK) activity and lymphokine-activated killer (LAK) activity in children during and after treatment for ALL. We observed that peripheral blood mononuclear cells in 22 children undergoing maintenance chemotherapy displayed significantly depressed NK activity compared with normal controls even when the proportion of NK cells was normal. LAK activity was also considered in 43 ALL children during and after maintenance chemotherapy. We observed that LAK activity was persistently comparable with that of normal controls. It seems definite that NK activity impairment is transient and is completely restored in ALL children a few months after chemotherapy has been successfully completed. The evidence that LAK activity is not impaired in ALL children may have some implications in view of a possible immunomodulatory approach in the presence of refractory disease.

Antibodies, Monoclonal↗
PubMed1986

Enhanced interleukin 1 and depressed interleukin 2 production in juvenile arthritis.

Blood mononuclear cells from a total of 23 children with juvenile arthritis were stimulated in vitro to produce interleukin 1 (IL-1) and interleukin 2 (IL-2) and compared with age matched healthy controls. Peripheral blood monocytes from patients with juvenile arthritis produced a higher amount of IL-1 than controls, whereas peripheral blood lymphocytes from the same patients produced lower amount of IL-2 than controls. These findings could not be explained by concurrent therapy. The increase of IL-1 production was more marked in patients with active disease and therefore may have been secondary to the pathological process. However, the decrease of IL-2 production did not depend on disease activity, thus suggesting an immunoregulatory abnormality.

Adolescent↗
PubMed1986

Lymphocyte subpopulations in the neonate: in vitro proliferation, IL-1 and IL-2 production by a subset of HNK-1-, OKT3-, OKT8+ lymphocytes displaying NK activity.

Neonatal lymphocytes include a subset of E-, OKT3-, OKT4-, OKT8+, HNK-1-, OKM1- cells displaying natural killer (NK) activity. More than 50% of these cells react with the B73.1 monoclonal antibody, moreover most of them bear the DR antigen, the receptor for Peanut agglutinin (PNA) and react with the OKT10 monoclonal antibody. This neonatal subset displays a higher NK activity than unseparated cord blood lymphocytes (CBL) and the present study shows that it is sensitive to boosting effect of IFN-B preincubation. When stimulated with T cell mitogens E-, OKT3-, OKT8+ CBL both produce Interleukin-2 (IL-2) and proliferate. Moreover this neonatal subset produces Interleukin-1 (IL-1) both spontaneously and in response to lipopolysaccharide (LPS). It has been previously suggested that these neonatal cells include a common precursor of NK and T cells. The present study further strengthen this hypothesis.

Antibodies, Monoclonal↗
PubMed1985

Interaction between photoreceptors and pigment epithelium in developing pigeon retina: an electrophysiological and ultrastructural study.

In pigeons as in other vertebrates, the electroretinogram (ERG) first can be recorded simultaneously with the appearance of the photosensitive lamellae in the developing outer segments. At around 4-6 days after the bird has hatched a small negative-positive complex (a-b-wave) appears. Simultaneously, a c-wave can be recorded and the termination of the stimulus is followed by a positive d-wave. The ERG amplitude progressively increases during the first month as the lamellar structures complete their maturation. The c-wave amplitude shows a steady increase in the early post-hatching period which parallels the a-b complex maturation. In newly hatched pigeons the retinal pigment epithelial (RPE) cell consists of a small soma and long villi which extend toward the photoreceptors. During maturation a progressive increase in RPE thickness and number of cytoplasmic elements can be observed.

Animals↗
PubMed1985

Developing pigeon retina: light-evoked responses and ultrastructure of outer segments and synapses.

Morphological development of photoreceptor outer segments and synapses in the foveal region of the pigeon retina was studied by electron microscopy. In addition, the maturation of outer retina function was investigated by recording electroretinographic (ERG) responses to either flash or pattern stimuli. The first ERGs to unpatterned or patterned stimulation can be recorded at 4-6 days posthatching. These results are consistent with anatomical analysis of pigeon photoreceptor and synapse development. Indeed, photosensitive lamellae in the outer segments can be observed simultaneously with the appearance of the first retinal responses to light. A few synapses can already be seen in the outer plexiform layer at the time photoreceptor disks first appear. In contrast, numerous synapses are already present in the inner plexiform layer when photoreceptor lamellae have yet to appear. A comparable maturation pattern has been reported to occur in chicks toward the end of the incubation time.

Animals↗
PubMed1982

Isolated popliteal versus distal bypasses for limb salvage.

The results of 54 bypass procedures--22 to an isolated popliteal segment and 32 to an infrapopliteal major calf vessel for limb salvage--were evaluated. After a distal bypass, the elevation of systolic pressure at the ankle was greater than that observed following a bypass to an isolated popliteal segment. However, healing times for ischemic lesions of the foot were comparable for each procedure. Patency and limb salvage rates for saphenous vein and polytetrafluoroethylene isolated popliteal segment bypasses were similar to those obtained with vein bypass grafts to infrapopliteal major calf vessels. In contrast, when polytetrafluoroethylene was used for a distal bypass below the popliteal artery, the failure rate was higher in the first year, with subsequent limb loss. These data suggest that, when a bypass operation is undertaken in the lower extremity for limb salvage, a bypass to an isolated popliteal segment, using either saphenous vein or polytetrafluoroethylene, is preferable to a polytetrafluoroethylene infrapopliteal bypass.

Amputation, Surgical↗
PubMed1980

[4 cases of tricholeukocytic leukemia].

The clinical, haematological, cytomorphological, cytochemical, ultrastructural, and bone marrow biopsy histological data observed in 4 cases of tricholeukocytic leukaemia are reported, along with some unusual findings. Stress is placed on the varied course of this disease and the difficulties associated with its treatment. Some criteria for the choice of therapy are also proposed.

Aged↗
PubMed1978

Ultrastructure of meiosis-inducing (heterotypic) and non-inducing (homotypic) cell unions in conjugation of Blepharisma.

Cells of mating types I and II of Blepharisma japonicum interact with each other and unite in heterotypic (type I-type II) or homotypic (type I-type I, type II-type II) pairs. Heterotypic pairs undergo meiosis and other nuclear changes of conjugation, while homotypic pairs remain united for days without the nuclear changes taking place. We compared cell unions of these two kinds of pairs at the ultrastructural level. In the homotypic union, cell membranes are closely juxtaposed, separated by a distance of about 20 nm. This arrangement is interrupted in some places by vacuoles and small cytoplasmic bridges. Saccule-like structures tend to be more abundant near the united surfaces. Microtubules running at right or slightly obtuse angles with the cell surface (PACM microtubules) are characteristically present at the united region of cells. These structures are very similar to those observed in earlier stages of the heterotypic union. However, in homotypic pairs, cells unite only at the anterior half of the peristome, while in heterotypic pairs cells unite also at the posterior half of the peristome, where the cell membrane totally disappears in later stages. PACM microtubules persist for at least 18 h in homotypic unions, while they disappear within a few hours in heterotypic unions. These differences between the two kinds of cell union are discussed in relation to the initiation mechanism of meiosis and other nuclear changes of conjugation. Similarities between homotypic union and cell junctions in multicellular organisms are also discussed.

Animals↗
PubMed1976

Olfactory nerve reconstitution in the homing pigeon after resection: ultrastructural and electrophysiological data.

Homing pigeons were subjected to uni- or bilateral resection of the olfactory nerves. A control of the operated region carried out five months later, showed that the olfactory nerves were continuous from the olfactory mucosa to the bulb. Cross sections of the regenerated nerve, observed under the electron microscope, showed morphological alterations with respect to the normal. Total measurement of the cross surface of both olfactory nerves showed that the regenerated nerve is always smaller than the intact nerve; this is also apparent in the total number of the fibres counted. Electrophysiological tests, performed on the regenerated nerve showed that the conduction along the resected nerve is restored.

Animals↗
PubMed1976

Degenerative and regenerative processes in the olfactory system of homing pigeons.

Experimental resection of the olfactory nerve in the homing pigeon induces a total degeneration of the nerve and olfactory epithelium. The orthograde degenerative process starts before the retrograde one. Ten days after resection, new neurons begin to differentiate from the basal cells. The axon forms earlier than the distal dendritic process, and the speed of growth increases slowly. The regenerated axons only reach the bulb in the 5th month. Two months after resection the olfactory epithelium is similar to that of the intact control side. The ultrastructural features of the mucosa and olfactory axons are similar to those of normal ones.

Animals↗
PubMed1975

Fine structural observations on the ciliary receptors in the epidermis of three otoplanid species (Turbellaria proseriata).

In Notocaryoturbella bigermaria, Otoplana truncaspina and Paroto-planella heterorhabditica three types of epidermal receptors are recognized. Type I: with a single cilium running in a duct, piercing the distal dendrite process of the receptor. The internal wall of the dendrite process has eight ridges with longitudinal filaments lying inside them. The ciliary basal body lacks a longitudinal rootlet but is encircled by a thin annular formation. Type II: with a single (A) or several (B) cilia which protrude from the outer epithelial surface and are provided with a large and striped rootlet. Both types are considered as mechanoreceptors. Type III: with two or more short and stumpy cilia devoid of rootlets and displaying the usual 9 + 2 pattern in the proximal part only. They are considered as chemoreceptors.

Animals↗
PubMedDate not supplied

Fetal amino acids in normal pregnancies and in pregnancies complicated by intrauterine growth retardation.

Plasma amino acid concentrations were measured in normal (AGA) and intrauterine growth retarded (IUGR) percutaneous umbilical blood sampling (PUBS) performed for prenatal diagnosis or at elective cesarean section. IUGR fetuses present significantly lower concentrations of most amino acids, with a significant reduction of the umbilical veno-arterial difference for total alpha-amino nitrogen. These findings are present early in growth retarded fetuses and may be potentially responsible for the growth retardation.

Amino Acids↗