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Biomedical subjects

A Modica

Publications and source records attributed to A Modica.

At least 37 records · Page 2Linked to original sources
PubMed1993

Ultrastructural evidence of the mechanisms responsible for interleukin-4-activated rejection of a spontaneous murine adenocarcinoma.

The ultrastructural pattern of the anti-tumor response elicited by interleukin-4 (IL-4) was investigated by using a spontaneous mammary adenocarcinoma (TS/A) unable to elicit protective immunity in syngeneic BALB/c mice as suggested by a variety of preimmunization-challenge experiments. A subcutaneous lethal challenge of TS/A tumor cells was inhibited in a significant number of BALB/c mice receiving recombinant murine IL-4 injected daily for 10 days around the tumor-draining lymph node. Tumor rejection was mainly the result of direct membrane and cytoplasmic damage to tumor cells by eosinophils, neutrophils and macrophages that deeply penetrated the proliferating tumor mass. Lymphocytes and fibroblasts participated in the reaction by interacting with tumor cells, granulocytes and each other. The most frequent cell interactions in the peri- and intra-tumoral areas and in the tumor-draining lymph nodes are illustrated. The efficiency with which the IL-4-activated reaction leads to tumor inhibition and induction of a T-lymphocyte-dependent tumor-specific immune memory appears to depend on interactions between distinct leukocytes.

Adenocarcinoma↗
PubMed1991

[Extracellular matrix in gingival fibroblasts].

Primary cultures of human gingival fibroblasts from patients of different age have been established. Histotype characterization has been confirmed by ultrastructural morphology and by the positivity of intermediate filament vimentin. Extracellular matrix expression has been analyzed by immunocitochemistry. Our data demonstrate that the extracellular matrix of human gingival fibroblasts is composed of type IV collagen, other than fibronectin and type I-III collagens.

Cells, Cultured↗
PubMed1991

Fish plasma lipoproteins--comparative observations in serranides and sparides.

1. Diet, time from last feeding, temperature, season and sexual stage are some of the factors influencing the lipoprotein pattern. 2. Keeping these factors constant species-specific differences observed among lipoprotein patterns of Sparus aurata, Puntazzo puntazzo, Diplodus sargus, Diplodus vulgaris and Dicentrarchus labrax are discussed. 3. Feeding habits and therefore lipid absorption and the rate of lipoprotein maturation process are the factors determining the observed differences.

Animals↗
PubMed1991

Nerve conduction velocity and circulating immunocomplexes in type 1 diabetic children.

There is evidence from several laboratories of an increased prevalence of circulating immuno-complexes (CIC) in diabetic patients. It has also been suggested that CIC are pathogenetically related to chronic diabetic complications. The aim of this study was to assess peripheral nerve function in children with Type 1 diabetes and to evaluate the relationship between the neurophysiological abnormalities and the possible presence of CIC. The investigation was carried out in 25 Type 1 diabetic patients ranging in age from 7-19 years and in 20 normal controls. Neurophysiological assessment was performed to evaluate motor and sensory conduction velocity on median and tibial nerves. IgG-CIC were detected by the solid-phase C1q-binding and anti-C3 enzyme immuno-assay. The results of this study showed a greater slowing of median motor and sensory and tibial sensory conduction velocities in patients with CIC with respect to the patients without CIC, suggesting a possible role of immunological factors in the pathogenesis of diabetic neuropathy.

Adolescent↗
PubMed1991

F-wave study at different stimulation rates.

In 50 ulnar nerves of healthy subjects, F-wave latency, duration, amplitude and persistence were determined at different frequencies of the antidromic impulse (0.2-0.5-1-2 Hz). The F amplitude and persistence were found significantly increased at higher stimulation rates, suggesting that the frequency of the antidromic impulse influences the motoneuron pool discharges. Individual cross-correlation values (r) obtained for latency and duration, latency and amplitude, amplitude and duration did not show any significant changes at different stimulation rates.

Adolescent↗
PubMed1990

Analysis of F response in upper motoneurone lesions.

The F response can provide a measure of motoneurone excitability (MNE) and so it may be used to investigate upper motoneurone disorders. This report studies the F-wave configuration in patients with stroke to evaluate the changes of the central excitability of the motoneurones at different times after an acute cerebral insult. Various parameters of the F response, including amplitude (absolute and F%/M), duration, and persistence have been determined in 26 patients with unilateral hemiplegia and in 32 healthy subjects of both sexes in the same age range. The investigation was carried out applying a series of 20 supramaximal stimuli at 0.5 Hz on tibial and ulnar nerves bilaterally. In all patients a detailed clinical examination and a CT scan were performed. Our results indicate that an initial stage of reduced spinal motoneuron excitability evidenced by a decreased F amplitude and persistence was present in the early phases after a stroke, followed within 90 days by an enhanced MNE. Moreover, F-wave amplitude shows a positive correlation with weakness and increased tone.

Adult↗
PubMed1990

F-response assessment in healthy control subjects.

Various parameters of the F-response (latencies, chronodispersion, amplitude, duration, shape, persistence) were investigated in ulnar and tibial nerves of 50 healthy subjects of both sexes, aged between 16 to 79 years. The observations were made bilaterally and the results revealed no significant differences in any of the F-parameters by comparing side to side. The relationships between each neurophysiological F-response data and limb length, age and sex of control subjects were determined. Correlations of high statistical significance were found between minimum F-latency and limb length as well as between absolute and F%/M-amplitude and age. Cross-correlation coefficients correlating mean individual values of latency-duration, latency-amplitude and amplitude-duration did not show any significant relationship between latency, amplitude and duration in normal subjects.

Adolescent↗
PubMed1989

Conduction velocity study in type 1 diabetic patients.

The role of metabolic abnormalities in the development of diabetic neuropathy is controversial. To investigate the peripheral nerve function and the influence of hyperglycemia on nerve conduction in insulin-dependent diabetes, a one-year neurophysiological study was carried out in 30 type 1 diabetic patients ranging in age from 2-16 years. During the 12-month follow-up period the glycosylated hemoglobin determination, motor conduction velocity of the peroneal nerve and the motor and sensory conduction of the tibial nerve were assessed 3 times, at the beginning of the study and every 6 months thereafter. The sensory latency was found significantly delayed in these patients as compared with the controls. The degree of sensory conduction slowing correlated well with the glycosylated hemoglobin concentrations and improved with the reduction in hyperglycemia.

Adolescent↗
PubMed1988

The application of F wave measurements in hepatic patients.

The ulnar and tibial nerve F response latencies were analyzed to study the proximal motor conduction velocity in 15 patients with liver disease. The results were compared with those obtained from 15 normal subjects. The tibial MNCV (P less than 0.01) and FWCV from spinal cord to elbow and knee for ulnar and tibial nerves (P less than 0.001) were significantly reduced in patients compared to the controls. Minimum, mean and maximum F latencies showed significant differences for ulnar (P less than 0.001) and tibial (P less than 0.01) nerves in patients with respect to the controls. The mean F determination compared to the minimum F and delta F did not improve disease identification. The conduction abnormality in hepatic patients appeared to be present only in the proximal segment of the ulnar nerve, whereas it was more uniformly distributed along the entire length of the tibial nerve. This demonstrates that the peripheral nerve involvement in hepatic disease is more diffusely present than can be determined by conventional conduction study only.

Adult↗
PubMed1988

[Audio-vestibular changes in patients with rheumatoid arthritis].

A functional audio-vestibular investigation based on impedance metric techniques and electronystagmography was carried out in a group of patients with "classical" rheumatoid arthritis (RA) and with treated or untreated "definite" RA in various stages. Data obtained from these patients were compared with those obtained from a control group. Significant hypoacusis of the transmissive type was found in initial stages of RA while sensorineural or mixed type hypoacusis was found in later stages of RA. Significant vestibular alterations of the central type suggesting supratentorial involvement were found in several cases independently of the stage of RA and of the age of the patients.

Acoustic Impedance Tests↗
PubMed1987

Analysis of F-wave in metabolic neuropathies: a comparative study in uremic and diabetic patients.

Motor nerve conduction study along the entire length of the ulnar and tibialis posterior nerves was carried out in 30 diabetics compared with 30 uremic patients and 30 control subjects. The conduction in the proximal and the distal nerve segments was evaluated by the determination of the M and F latencies, MNCV (between the stimulus sites), FWCV (between the spinal cord and the stimulus sites), and F-ratio (conduction time ratio of proximal to distal segment). In both groups of patients the lower limbs appear much more involved than the upper, where the ulnar nerve is more commonly affected in uremic than in diabetic patients. In diabetic neuropathy the motor conduction abnormalities are diffuse over the total length of the nerve, but more marked distally in the ulnar nerve.

Action Potentials↗
PubMed1986

F-wave study in patients with chronic renal failure on regular haemodialysis.

Motor nerve conduction along the entire length of ulnar and tibialis posterior nerves was studied in 30 uraemic patients and in 20 control subjects. The M and F latencies, MNCV (between the stimulus sites), FWCV (between the spinal cord and the stimulus sites) and F-ratio (conduction time ratio of proximal to distal segment) were assessed to evaluate the conduction in the proximal versus the distal nerve segment. In the uraemic patients, the slowing of nerve conduction involved both segments of the tested nerves to the same extent. In fact, the F-ratio did not show any significant difference between the two groups; in only one patient was its value lower than the normal limit in the tibialis posterior nerve.

Adolescent↗
PubMed1984

Functional properties of the whole blood in a carrier of Hb-Atlanta: beta 75 (E-19) Leu-Pro.

The Authors illustrate the main functional parameters of the whole blood in a heterozygous carrier of the unstable Hb-Atlanta. The most important results are represented by a right-shifted P50, by a lowered value of n and by an almost normal pH-depending Bohr effect. It is very likely that the first report depends on the relative Hb-A deficiency, whereas the second one could be due to the presence of the unstable Hb. Moreover, the linkage between this latter and DPG would be present.

Blood Physiological Phenomena↗
PubMed1984

The oxygen affinity of normal human whole blood measured by double tonometry. I. P50 and n factor.

The Authors refer that the oxygen affinity, determined by double tonometry, in normal adult whole blood, is mainly expressed by a P50 of 26.13 +/- 4.31% and by an n factor of 2.63 +/- 6.63%. These results are in good agreement with those reported in the literature, but here are some doubts that pO2 and SO2 alone, i.e. the data drawn from all the tonometric procedures, can give a full idea of the affinity. In fact, this one is a complicate process, modulated by a number of allosteric effectors. Most of them, like pH, temperature and pCO2 can be always kept at a fixed standard level, whereas DPG, the main one, cannot.

Adolescent↗
PubMed1984

The oxygen affinity of normal human whole blood measured by double tonometry. II. pH-depending Bohr effect and DPG.

Following another preliminary work on the whole blood oxygen affinity, the Authors have found in this occasion normal values of the pH-depending Bohr effect in healthy subjects of both sexes and different age. Furthermore, the Hb decreasing causes in these cases also a P50 increasing which is mediated by raised DPG levels. However, while in the anemias this effect is constant, many exceptions have been found in physiological conditions. Since these ones have been mainly detected at the maximal DPG levels, the phosphate could modify the affinity not only as allosteric effector, but also by acting on pH and related equilibria as non diffusible free anion. These interferences are difficult to be calculated and often could disturb notably a correct use of the common mathematical model which describes the oxygenation.

Adolescent↗
PubMed1980

[Prostaglandins and peptic ulcer disease].

The action of prostaglandins with regard to ulcers is made clear by their inhibition of gastric secretion, on the one hand, and their so-called cytoprotective effect, on the other. Experimental data are used in a summary of the explanations offered of the mechanisms underlying these two effects. In addition, attentions is directed to the possible rôle of the prostaglandins in gastric physiology, and hence in the physiopathology of ulcers. The therapeutic results obtained with prostaglandins in the management of gastroduodenal ulcer offer firm grounds for supposing that further developments will take place in the clinical field.

Animals↗