Biomedical subjects

R Cadossi

Publications and source records attributed to R Cadossi.

At least 37 records · Page 2Linked to original sources

PubMed1996

Pathways of transmission of ultrasound energy through the distal metaphysis of the second phalanx of pigs: an in vitro study.

Ultrasound (US) has been studied by several researchers to assess its possible use in screening for osteoporosis; among other sites the phalanxes have been proposed as a possible site for investigation with US. In the present experimental work we studied the morphostructural characteristics of the second phalanx of the pig; then, in vitro, we investigated the behaviour of an ultrasound signal at 1.25 MHz crossing the distal metaphysis of the second phalanx. In particular, we studied the effects of milling or drilling on US velocity, and on the energy and shape of the signal generated by the US at the receiving probe. We demonstrated that the US velocity decreases by an average of 496 m/s (-21%) when axial perforations are made in the central marrow. A decrease is also noted in the number of peaks, and the normalized energy of the US signal received falls on average by 11.3 mV microseconds (-84%). The characteristics of the signal at the receiving probe can be broadly reconstituted if, after extensive drilling, the bone cavity is filled with polymerized styrene resin. In contrast, if phalanx milling is performed to remove the outermost bone tissue, the normalized energy increases by 15.5 mV microseconds (+84%) and the velocity of US increases by 163 m/s (+7%). It was also noted that the complexity of the signal received (i.e. number of peaks) and the signal normalized energy depend on the integrity of the bone structures traversed. The results reported here provide useful indications for interpreting the findings of clinical investigations with US, most specifically those performed on the phalanx of the hand.

Animals↗

PubMed1994

Protection against focal cerebral ischemia following exposure to a pulsed electromagnetic field.

There is evidence that electromagnetic stimulation may accelerate the healing of tissue damage following ischemia. We undertook this study to investigate the effects of low frequency pulsed electromagnetic field (PEMF) exposure on cerebral injury in a rabbit model of transient focal ischemia (2 h occlusion followed by 4 h of reperfusion). PEMF exposure (280 V, 75 Hz, IGEA Stimulator) was initiated 10 min after the onset of ischemia and continued throughout reperfusion (six exposed, six controls). Magnetic resonance imaging (MRI) and histology were used to measure the degree of ischemic injury. Exposure to pulsed electromagnetic field attenuated cortical ischemia edema on MRI at the most anterior coronal level by 65% (P < 0.001). On histologic examination, PEMF exposure reduced ischemic neuronal damage in this same cortical area by 69% (P < 0.01) and by 43% (P < 0.05) in the striatum. Preliminary data suggest that exposure to a PEMF of short duration may have implications for the treatment of acute stroke.

Animals↗

PubMed1994

Reducing the risk of viral transmission at operation by electronic monitoring of the surgeon-patient barrier.

A new electronic device designed to detect glove holes, wet gowns and glove permeability was assessed during 50 general surgical operations. The cause of each alarm was recorded and the surgeon's awareness of any breach noted. Some 266 alarms were recorded of which 45 were ascribed to glove holes, 86 to wet gowns, 115 to glove porosity and 20 to other causes. Glove holes occurred in 29 of the 50 procedures; the surgeon was unaware of the hole in almost 70 per cent of cases. Holes were more common in laparotomy than in laparoscopic procedures (P = 0.006). In 20 per cent of instances surgeons did not respond immediately to the alarm (median delay 16 min). Six of eight surgeons who used the device indicated that they would do so regularly for major abdominal surgery. The electronic system accurately detects breaches in the surgeon-patient barrier. Its use should improve surgical discipline in acting to restore the barrier, protecting patient and surgeon alike.

Elective Surgical Procedures↗

PubMed1994

Effect of electromagnetic fields on patients undergoing massive bone graft following bone tumor resection. A double blind study.

Massive bone allograft after tumor resection has been used for over 20 years. Many factors negatively influence the healing of the junction between the allograft and the host bone, resulting in a low healing rate and lengthy time to union. This study evaluated whether pulsing electromagnetic field stimulation could be advantageously used in these patients. A double blind prospective randomized study was designed. Eighty three host graft junctions in 47 patients were considered. The overall host graft junction healing rate was the same (67%) in both control and active stimulated patients. Although not statistically significant, a positive effect of pulsing electromagnetic fields was observed for those host graft junctions with a cortico-cortical contact between allograft and host bone. When adjuvant postoperative chemotherapy was not employed, a definite effect of pulsing electromagnetic field stimulation was observed: the healing time decreased from 9.4 months in the control group to 6.7 months in the active stimulated group (p < 0.001). This effect would have been lost if chemotherapy was employed. There was also no advantage in supplement with iliac crest autografts at the host graft junction site if chemotherapy was used. Factors that significantly influenced the host graft junction healing rate were: chemotherapy; type of allograft host bone contact; quality of host graft junction; and, in intercalary allografts, use of the osteosynthesis device. No difference was observed between control and active groups for patient survival or number of local or distal tumor recurrences.

Adolescent↗

PubMed1993

Exposure to low frequency pulsed electromagnetic fields increases interleukin-1 and interleukin-6 production by human peripheral blood mononuclear cells.

The exposure of human peripheral blood mononuclear cells to extremely low frequency pulsed electromagnetic fields (PEMFs) increased both the spontaneous and the PHA- and TPA-induced production of interleukin-1 (IL-1) and IL-6. Our results suggest that cells of the monocytic lineage, which are good producers of both IL-1 and IL-6, can be important cellular targets for PEMFs. Taking into account that these cytokines are among the most pleiotropic ones, these data can help us understand the previous reported effects of PEMFs on the proliferation of human lymphocytes and the effects exerted by such fields on cartilage and bone cells, whose physiological activity is highly dependent on IL-1 and IL-6.

Adult↗

PubMed1993

The electrical stimulation of tibial osteotomies. Double-blind study.

The effect of electromagnetic field stimulation was investigated in a group of 40 consecutive patients treated with valgus tibial osteotomy for degenerative arthrosis of the knee. All patients were operated on by the same author and followed the same postoperative program. After surgery, patients were randomly assigned to a control group (dummy stimulators) or to a stimulated one (active stimulators). Four orthopedic surgeons, unaware of the experimental conditions, were asked to evaluate the roentgenograms taken 60 days postoperatively and to rate the osteotomy healing according to four categories (the fourth category being the most advanced stage of healing). In the control group, 73.6% of the patients were included in the first and second category. In the stimulated group, 72.2% of the patients were included in the third and fourth category. On a homogeneous group of patients, electromagnetic field stimulation had positive effects on the healing of tibial osteotomies.

Adult↗

PubMed1992

Lymphocytes and low-frequency electromagnetic fields.

Human lymphocytes have been used by several researchers to investigate the biological effect of electromagnetic fields (EMF). EMF modulate the response by lymphocytes to lectin stimulation. The size and direction of the effect depends both on the lymphocyte physiology and on the physical parameters characterizing the EMF. Lymphocytes have also been used to investigate the genotoxicity of EMF exposure.

Electromagnetic Fields↗

PubMed1991

Spontaneous and mitomycin-C-induced micronuclei in human lymphocytes exposed to extremely low frequency pulsed magnetic fields.

The cytokinesis block micronucleus method, a very sensitive cytogenetic assay, was used to ascertain the possible genotoxic effects of extremely low frequency pulsed magnetic fields in phytohemagglutinin-stimulated human lymphocytes cultures from 16 healthy donors. Four conditions were studied: i) lymphocytes not exposed to the field (control cultures); ii) lymphocytes exposed to the field; iii) lymphocytes treated with mitomycin-C and not exposed to the field; iv) lymphocytes treated with mitomycin-C and exposed to the field. Mitomycin-C-treated cultures were used as control for the micronucleus method, because it is known that mitomycin-C is a potent genotoxic agent, capable of inducing micronuclei. The frequency of micronuclei in field-exposed cultures was similar to the spontaneous frequency observed in control unexposed-cultures. Moreover, the exposure to pulsed magnetic fields did not affect the frequency of micronuclei induced by mitomycin-C, suggesting that, in the experimental conditions used, this kind of field neither affected the integrity of chromosomes nor interfered with the genotoxic activity of mitomycin-C.

Alkylating Agents↗

PubMed1991

Exposure to low-frequency pulsed electromagnetic fields increases mitogen-induced lymphocyte proliferation in Down's syndrome.

We previously reported that exposure of human mitogen-stimulated peripheral blood lymphocytes (PBL) to extremely low frequency pulsed electromagnetic fields (PEMFs) could restore the defective proliferative capability of PBL from aged subjects. The effects of exposure to PEMFs were studied in PBL from 25 patients with Down's syndrome (DS), a syndrome of premature aging characterized by precocious immune system derangement, including age-related defective PBL proliferative capability. PBL were stimulated with different doses of phytohemagglutinin, and cell proliferation was assessed by measuring the incorporation of tritiated thymidine. After PEMF-exposure, a significant increase in cell proliferation was observed in cells from DS children and young adults, but it was much more evident in PBL from relatively aged DS patients. The age-related effect of PEMFs on DS lymphocytes demonstrates that age must be considered a major variable when studies on DS are performed, and confirms that DS must be regarded as a syndrome of accelerated aging.

Adolescent↗

PubMed1991

Effect of low frequency low energy pulsing electromagnetic fields on mice injected with cyclophosphamide.

C3H mice have been used to investigate the effect of a combination of cyclophosphamide (CY) and electromagnetic fields (PEMF). Mice were injected i.p. with a single dose of 200 mg/kg body weight of CY and then exposed to PEMF 24 h per day. In an initial series of experiments immediately after CY injection mice were exposed to PEMF until sacrifice. WBC counts in the peripheral blood demonstrated a quicker decline in WBC at days 1 and 2 in mice exposed to PEMF. Groups of mice were sacrificed at days 1, 4, 6, 8, and 10 after CY injection. In mice exposed to PEMF the spleen weight was less than in controls at days 6, 8, and 10. Autoradiographic studies demonstrated that the labeling index of bone marrow smears did not significantly differ between controls and experimental mice exposed to PEMF, whereas the spleen labeling index proved to be higher among control mice versus mice exposed to PEMF at day 6, and higher among mice exposed to PEMF versus controls at day 8. In a second series of experiments mice were exposed to PEMF only over the 24 h following CY injection. We found that the spleens of mice exposed to PEMF weighed less than those of controls at days 6 and 8. The labeling index of bone marrow did evidence a slight decrease among mice exposed to PEMF at days 8 and 10 after CY injection versus control mice. The spleen labeling index proved to be lower in experimental mice exposed to PEMF than in controls at days 4, 6, and 8. Mice were then injected with CY, half were exposed to PEMF, and 24 h later bone marrow was recovered from both groups of animals. The same number of bone marrow cells was injected via the tail vein into recipient mice irradiated to 8.5 Gy. The grafting efficiency of the bone marrow was evaluated by examining the number of spleen colonies and the spleen and bone marrow labeling indices at day 8; all parameters proved to be significantly lower among mice grafted with the bone marrow of mice injected with CY and exposed to PEMF than among controls injected with CY only. Finally, we found th at the effect of PEMF is evident only if mice are exposed during the 24 h following CY injection. The data reported here indicates that PEMF exposure after CY injection increases the damage induced in mice by CY.

Animals↗

PubMed1990

Effect of low frequency pulsing electromagnetic fields on skin ulcers of venous origin in humans: a double-blind study.

The effect of an electromagnetic field on the healing of skin ulcers of venous origin in humans has been investigated in a double-blind study. Forty-four patients have been admitted to the study; one-half were exposed to active stimulators (experimental group) and the remaining to dummy stimulators (control group). The stimulation was scheduled to last a maximum of 90 days. The success rate was significantly higher in the experimental group both at day 90 (p less than 0.02) and in the follow-up period (p less than 0.005). The data suggest that the effect of the electromagnetic field lasts even when the stimulation is over. No ulcers worsened in the experimental group, while four worsened in the control group. Twenty-five percent of the patients in the experimental group and 50% in the control group experienced recurrence of the ulcer. It is concluded that stimulation with an electromagnetic field is a useful adjunctive therapy in the management of these patients.

Aged↗

PubMed1989

Extremely low frequency pulsed electromagnetic fields increase interleukin-2 (IL-2) utilization and IL-2 receptor expression in mitogen-stimulated human lymphocytes from old subjects.

The effects of the exposure of mitogen-stimulated human lymphocytes from aged subjects to low-frequency pulsed electromagnetic fields (PEMFs) were studied by measuring the production of interleukin-2 (IL-2) and the expression of IL-2 receptor. PEMF-exposed cultures that presented increased [3H]thymidine incorporation showed lower amounts of IL-2 in their supernatants, but higher percentages of IL-2 receptor-positive cells and of T-activated lymphocytes. Taken together, these data suggest that PEMFs were able to modulate mitogen-induced lymphocyte proliferation by provoking an increase in utilization of IL-2, most likely acting on the expression of its receptor on the plasma membrane.

Aged↗

PubMed1989

Extremely low frequency pulsed electromagnetic fields increase cell proliferation in lymphocytes from young and aged subjects.

The effect of the in vitro exposure to extremely low frequency pulsed electromagnetic fields (PEMFs) on the proliferation of human lymphocytes from 24 young and 24 old subjects was studied. The exposure to PEMFs during a 3-days culture period or during the first 24 hours was able to increase phytohaemagglutinin-induced lymphocyte proliferation in both groups. Such effect was greater in lymphocytes from old people which showed a markedly reduced proliferative capability and, after PEMF exposure, reached values of 3H-TdR incorporation similar to those of young subjects. The relevance of these data for the understanding and the reversibility of the proliferative defects in cells from aged subjects and for the assessment of risk related to the environmental exposure to PEMFs has to be considered.

Adult↗

PubMed1989

DNA repair after gamma irradiation in lymphocytes exposed to low-frequency pulsed electromagnetic fields.

The effect of exposure to extremely low-frequency pulsed electromagnetic fields (EMFs) on DNA repair capability and on cell survival in human lymphocytes damaged in vitro with gamma rays was studied by two different micromethods. In the first assay, which measures DNA repair synthesis (unscheduled DNA synthesis, UDS), lymphocyte cultures were stimulated with phytohemagglutinin (PHA) for 66 h and then treated with hydroxyurea (which blocks DNA replication), irradiated with 100 Gy of 60Co, pulsed with [3H]thymidine ([3H]TdR), and then exposed to pulsed EMFs for 6 h (the period in which cells repaired DNA damage). In the second assay, which measures cell survival after radiation or chemical damage, lymphocytes were first irradiated with graded doses of gamma rays or treated with diverse antiproliferative agents, and then stimulated with PHA, cultured for 72 h, and pulsed with [3H]TdR for the last 6 h of culture. In this case, immediately after the damage induced by either the radiation or chemicals, cultures were exposed to pulsed EMFs for 72 h, during which cell proliferation took place. Exposure to pulsed EMFs did not affect either UDS or cell survival, suggesting that this type of nonionizing radiation--to which humans may be exposed in the environment, and which is used for both diagnostic and therapeutic purposes--does not affect DNA repair mechanisms.

Adolescent↗

PubMed1989

Effect of low frequency low energy pulsing electromagnetic field (PEMF) on X-ray-irradiated mice.

C3H/Km flora-defined mice were used to investigate the effect of exposure to pulsing electromagnetic field (PEMF) after total body x-ray irradiation. Prolonged exposure to PEMF had no effect on normal nonirradiated mice. When mice irradiated with different doses of x-ray (8.5 Gy, 6.8 Gy, and 6.3 Gy) were exposed to PEMF 24 h a day, we observed a more rapid decline in white blood cells (WBC) in the peripheral blood of mice exposed to PEMF at all the x-ray dosages used. No effect of exposure to PEMF was observed on the survival of the mice irradiated with 6.3 Gy and 8.5 Gy; in mice irradiated with 6.8 Gy, 2 out of 12 survived when exposed to PEMF as compared to 10 out of 12 control mice that were irradiated only. At day 4 after irradiation autoradiographic studies performed on bone marrow and spleen of 8.5-Gy-irradiated mice showed no difference between controls and mice exposed to PEMF, whereas on 6.8-Gy mice the bone marrow labeling index was lower in mice exposed to PEMF. In mice irradiated to 6.3 Gy we observed that the recovery of WBC in the peripheral blood was slowed in mice exposed to PEMF and their body weight was significantly lower than in control mice that were irradiated only. The spleen and bone marrow of the mice irradiated to 6.3 Gy and sacrificed at days 4, 14, 20, and 25 after irradiation were analyzed by autoradiography to evaluate the labeling index. Half of the spleens from mice sacrificed at day 25 after irradiation were used to evaluate the RNA content. Autoradiography showed that in the spleen and bone marrow of control mice, there were more cells labeled with [3H]thymidine at days 4 and 14 and less at days 20 and 25 after irradiation in comparison with mice irradiated and exposed to PEMF. The Northern blot analysis of histone H3 and p53 protein RNAs extracted from the spleens at day 25 after irradiation showed a slight increase in cycling cells among spleens of mice exposed to PEMF. We suggest that the exposure to PEMF immediately after x-ray irradiation results in increased damage.

Animals↗

PubMed1988

Electrical stimulation of human femoral intertrochanteric osteotomies. Double-blind study.

Low-frequency pulsing electromagnetic fields (PEMF) are being used in nonunion healing at several centers around the world. Much debate exists about quantification of PEMF effects, especially in humans where no randomized studies have been performed. The results of a double-blind treatment of 32 consecutive patients treated with femoral intertrochanteric osteotomy for hip degenerative arthritis are reported. Roentgenographic evaluation and callus density measurements performed with an image analyzer showed a statistically significant difference between controls and stimulated patients (p less than 0.01). In this extremely homogeneous patient population, PEMF stimulation favored osteotomy healing.

Adult↗

PubMed1986

Slow healing fractures: can they be prevented? (Results of electrical stimulation in fibular osteotomies in rats and in diaphyseal fractures of the tibia in humans).

The purpose of the study was to evaluate the possibility of preventing delayed union in fractures by the use of low-frequency pulsing electromagnetic fields (PEMFs). The study was conducted in two parts, both with control groups. Fibular osteotomies in rats and diaphyseal fractures of the tibia in humans were treated with and without electrical stimulation (PEMF). The rats were sacrificed on the 8th and 23rd days respectively in order to evaluate the histological picture of the repair callus and its mechanical resistance. In the human subjects, the clinical and radiological follow-up took into account various factors known to affect the rate of union in the various fracture groups. The results obtained suggest that PEMF stimulation is capable of accelerating and modulating the physiological process of union by its favourable effect on osteogenesis.

Adolescent↗

PubMed1984

Sequence complexity and diversity of polyadenylated RNA molecules transcribed in human myeloid cells. Leukemic myeloblasts and HL60 promyelocytes uninduced and induced to terminal differentiation with retinoic acid.

The kinetic composition of the polyadenylated RNAs of leukemic myeloblasts and HL60 promyelocytes was examined by the cDNA-poly (A) +RNA reassociation technique before and after the induction of differentiation with retinoic acid. The data obtained in the homologous hybridizations show the following main features: the sequence complexity of the total poly(A) +RNA molecules is 72,000 different sequences in leukemic myeloblasts, 64,000 in HL60 promyelocytes before induction and 26,000 after treatment of HL60 with retinoic acid; the number of sequences reacting as abundant is clearly higher in HL60 promyelocytes (5,000) than in leukemic myeloblasts (1,000), and the number decreases sharply after induction (300); the repetition frequency of the abundant and rare components is almost unchanged between leukemic myeloblasts and HL60 promyelocytes, while it is markedly increased after induction with retinoic acid. The heterologous reactions show that the observed differences in complexity are mainly related to the missing of rare sequences. Moreover, an important portion of sequences already present in leukemic myeloblasts has a definitely higher repetition frequency in HL60 promyelocytes. Finally, the most abundant sequences in HL60 cells after induction are already present before treatment. The data presented here suggest that, during human myeloid differentiation, important, possibly transcriptional, regulatory mechanisms of gene expression are active long after the first commitment event of the hemopoietic undifferentiated stem cell.

Adult↗