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Biomedical subjects

Michael F Angel

Publications and source records attributed to Michael F Angel.

7 recordsLinked to original sources
PubMed2003

Effects of static electromagnetic fields on characteristics of MG-63 osteoblasts grown in culture.

The effects of static electromagnetic fields (SEFs) on MG-63, a human osteoblast cell-line, were investigated. We examined proliferation, proline uptake and gene expression in an SEF approximately 1/728th the intensity of those previously reported. Cells were placed within an SEF apparatus (average field intensity of 0.618mT) with appropriate controls. Proliferation was measured by 3H-thymidine incorporation and showed a 34% decrease in cells exposed to SEF (P = .0001; N = 3). Proline, a major component of collagen necessary for bone formation by osteoblasts, incorporation was reduced 37% (P = 0.006; N = 3). Reverse-transcription-polymerase chain reaction revealed that collagen I, alkaline phosphatase, parathyroid hormone-receptor, and osteocalcin mRNA's were down regulated with the low intensity SEF. Exposure to very low SEFs affects the MG-63 osteoblasts in a manner that may be detrimental to bone formation.

Bone Neoplasms↗
PubMed2002

Biochemical evaluation of serum and flexor tenosynovium in carpal tunnel syndrome.

In total, 41 consecutive patients with "idiopathic carpal tunnel syndrome" and abnormal electrophysiologic findings who underwent carpal tunnel release were studied prospectively. The focus of this investigation was the evaluation of the levels of specific chemical mediators within the serum and flexor tenosynovium of these patients. Blood was collected from these patients within 1 week prior to carpal tunnel release, and flexor tenosynovium was obtained at time of surgery. Specimens were then analyzed to determine the levels of interleukins 1 and 6, prostaglandin E(2) (PGE(2)), and malondialdehyde bis diethyl acetal. These values were compared to those of controls who had no evidence of carpal tunnel syndrome. A significant increase was noted in the serum malondialdehyde and tenosynovial levels of malondialdehyde, interleukin 6, and prostaglandin PGE(2) compared to controls. The elevated levels of these biologic factors and the absence of interleukin 1 elevation support a noninflammatory ischemia-reperfusion etiology for so-called "idiopathic carpal tunnel syndrome" that causes progressive edema and fibrosis of the tissues within the carpal canal. These findings correlate with previous histopathology reports. We believe that "idiopathic carpal tunnel syndrome" is an "-osis" not an "-itis."

Carpal Tunnel Syndrome↗
PubMed2002

Beneficial effect of hyperbaric oxygen on island flaps subjected to secondary venous ischemia.

The potential for hyperbaric oxygen therapy (HBO) to decrease the untoward effects of a secondary ischemic event was studied in the rat superficial epigastric flap model. The secondary venous ischemic flap was created by cross-clamping the vascular pedicles for 2 h. Twenty-four hours later, the flap was reelevated and the venous pedicle was occluded for 5 h. Thirty-two rats were divided into three groups. In experimental group 1, animals received HBO treatment immediately prior to the initial flap elevation and ischemia at 2 atmosphere pressures for 90 min. In experimental group 2, the rats underwent a similar course except for a second 90-min HBO course immediately prior to the secondary venous occlusion. The rats without HBO therapy were used as controls. The results showed that all control flaps were nonviable at 1 week by clinical inspection and fluorescein injection. Complete flap survival occurred in 20% of group 1 flaps and 30.8% of group 2 flaps. Partial flap survival occurred in the rest of the flaps in these two groups, with mean survival areas of 48% and 55%, respectively. In conclusion, HBO treatments significantly increase the survival of flaps subjected to a secondary ischemia, even if administered before the primary ischemia. Administering HBO prior to secondary venous ischemia was marginal, which may be due to the effect of O(2) given by HBO not lasting longer than 5 h.

Animals↗
PubMed2002

Role of free radicals in necrosis of skin graft compromised with hematoma.

It has been observed previously that a hematoma affects skin flap survival adversely through free radical action. The current study was undertaken to determine whether similar mechanisms are operative in skin grafts. The experiment was divided into two parts. During part I, 2 x 2 cm2 split-thickness skin grafts (STSGs) were harvested from 18 Fischer rats and were divided randomly into three groups (each consisted of six grafts), and incubated with plasma, blood, and blood plus 70 mg deferoxamine for 48 hours respectively. Tissue samples were assayed for lipoperoxidation (malondialdehyde [MDA]), superoxide dismutase (SOD), and nitric oxide synthase (NOS). During part II, 36 STSGs were harvested and were divided randomly into three groups. The grafts were incubated as in part I for 48 hours. The STSGs were then affixed to the same dimension recipient beds created on the back of 36 inbred rats. Survival was evaluated 7 days postoperatively. The results showed that there was no significant difference in MDA and NOS levels between each incubated graft group in part I. Only the SOD level in both grafts incubated with plasma and blood plus deferoxamine were significantly higher than the grafts over blood alone (p < 0.05). During part II, there was no significant difference of the average STSG survival percentage between the groups incubated with blood and blood plus deferoxamine (35.8 +/- 6.5% and 52.0 +/- 9.5%). The survival percentage of the group incubated with plasma was 81.8 +/- 7.3%, which was significantly higher than the other two groups (p < 0.01). The authors concluded that unlike a distal flap model, the pathological importance of free radicals in survival of the STSG over a hematoma is insignificant. A more likely hypothesis, as suggested by others, is that a hematoma serves as a barrier preventing angiogenesis.

Animals↗
PubMed2002

Chronic headache as a sequela of rigid fixation for craniosynostosis.

Rigid fixation has been used over the past 20 years for the long-lasting correction of traumatic and congenital craniofacial defects. It has been noted that the use of plates and screws can result in the migration of the hardware through the skull to the inner cerebral cortex where it embeds in the dura. In addition, there is controversy concerning the safety of using titanium plates in the pediatric population. We report here on an 8-year-old boy who presented to our clinic with a chronic headache after rigid craniofacial fixation using titanium plates 7 years before.

Bone Plates↗
PubMed2002

Necrotizing fasciitis of the upper extremity resulting from a water moccasin bite.

Aeromonas hydrophila infection has been described as the cause of necrotizing fasciitis in patients with suppressed immune systems, burns, or trauma in an aquatic setting. We report a case in which severe necrotizing fasciitis involving hand, arm, chest, and lateral side of trunk, along with toxic shock, developed after the patient was bitten by a venomous snake. Mixed aerobic and anaerobic bacteria, including A hydrophila, were isolated from the wound culture. The patient was treated with antivenom, a diuretic regimen, broad spectrum antibiotics, and 18 separate surgical procedures. After the application of skin grafts, the wound completely healed. This case illustrates that a venomous snakebite may result in infection with A hydrophila and can cause severe necrotizing fasciitis. Early and aggressive surgical intervention should be implemented as soon as the necrotizing fasciitis is diagnosed.

Adult↗