Biomedical subjects

B K Howard

Publications and source records attributed to B K Howard.

5 recordsLinked to original sources

PubMed1999

The effects of ultrasonic energy on peripheral nerves: implications for ultrasound-assisted liposuction.

The integration of ultrasound-assisted liposuction with traditional suction-assisted lipoplasty has extended the role of liposuction in body contouring. Although there are ample data regarding the effects of ultrasound on peripheral nerves from studies with the Cavitron ultrasound surgical aspirator, there is little information concerning the effects of modern ultrasound body contouring equipment on neural tissue. This study was designed to evaluate the functional and histologic effects of ultrasound energy on rat peripheral nerves (sciatic nerves) using a commonly-used ultrasound-assisted liposuction generator. After the application of ultrasound to exposed rat sciatic nerves, operative magnification was used to assess any visible injury. The sciatic function index was serially measured to quantify immediate and long-term functional effects on the nerves. Our results showed immediate visible injury using low amplitude settings (level 6), but no functional evidence of injury until much higher settings were used (level 9). All animals in the groups with initial functional impairment had returned to normal or near-normal function at completion of the study (51 days). Histologic examination revealed no evidence of damage in the low amplitude groups. Histologic analysis of the high amplitude groups displayed diffuse infiltration of the nerve, with foamy histiocytes and an increased number of mast cells, consistent with remote neural injury followed by myelin breakdown and repair.

Animals↗

PubMed1998

Osteoinduction using bone morphogenic protein in irradiated tissue.

OBJECTIVE: To prove the efficacy of bone morphogenic protein as an osteoinductive agent in irradiated tissue. DESIGN: Prospective randomized controlled trial designed to test the effectiveness of recombinant bone morphogenic protein 2 (rBMP-2) combined with solid hydroxyapatite disks in an irradiated tissue bed. SUBJECTS: Eighteen adult, male, white New Zealand rabbits weighing 3.0 to 3.5 kg. INTERVENTION: The rabbits were randomly divided, with 9 receiving radiation treatment and 9 receiving no radiation treatment. Each animal underwent implantation of 2 hydroxyapatite disks onto the snout at 9 weeks following radiation treatment. One disk was impregnated with rBMP-2 and the other with buffer only. The animals were killed at 3, 6, or 20 weeks after implantation for analysis. RESULTS: Histological analysis demonstrated that rBMP-2 was equally effective as an osteoinductive agent in the irradiated and nonirradiated tissue. We also found significantly increased new bone formation in the rBMP-2 group vs the buffer group. CONCLUSIONS: This study supports the potential clinical utility of rBMP-2 and solid hydroxyapatite in irradiated tissue beds. These findings have interesting implications for patients with head and neck cancer who have undergone radiation therapy and need bony reconstruction.

Animals↗

PubMed1998

The tissue effects of ultrasound-assisted lipoplasty.

The objective of our study was to investigate the effects of ultrasonic energy on tissues, using a porcine model, performed under various instrumental and procedural parameters. Domestic pigs were anesthetized and prepared for surgery. An incision was made on the side of the hip randomly assigned to the right or left side. Tumescence solution was infiltrated via a blunt tip, small diameter cannula, followed by performance of standard liposuction. On the contralateral side, a similar incision was made. For ultrasonic liposuction experiments without the sheath, a percutaneous introducer was inserted into the incision, which was protected at the entry site from contact with the cannula. Tumescence solution was infiltrated via a blunt tip, small diameter cannula, and then the site was treated with ultrasonic energy at maximum output from the machine with liposuction concurrent through the hollow cannula. The experiments with the sheath did not require a pretreatment with tumescence solution but consisted of tumescence solution pumped through the sheath at a low infusion rate, with concurrent treatment utilizing ultrasonically assisted liposuction through the central lumen of the cannula. In all cases, the lipoaspirate was preserved for biochemical analysis. After treatment, the pigs were euthanized, and samples for histopathology were taken. The pigs were then perfused with a radio-opaque solution through the left ventricle following preperfusion with saline. The groups were ultrasound-assisted liposuction with sheath (n = 3), ultrasound-assisted without sheath (n = 4), and tumescence alone (n = 1), with standard liposuction performed on the contralateral side for all ultrasound-assisted liposuction animals. The lipoaspirates from the ultrasonically assisted liposuction with the sheath showed significantly less blood loss (measured as hemoglobin in the aspirate) than standard liposuction (p = 0.012) at comparable levels of fat (measured as triglycerides in the aspirate). The lipoaspirates from ultrasound-assisted liposuction without the sheath showed blood loss comparable to that experienced with standard liposuction. The ratio of hemoglobin to triglyceride was lowest in the ultrasound-assisted group with (p = 0.01) and without (p = 0.06) the sheath when compared to traditional liposuction. In both of these treated groups, the radiograms of the perfused areas showed significantly less vascular disruption when compared with suction-assisted liposuction. Histopathologic examination of specimens taken from various treated areas showed substantial tissue damage comparable in ultrasound- and suction-assisted liposuction treated groups. This preliminary experimental study showed that ultrasound-assisted lipoplasty is comparable to traditional suction-assisted lipoplasty. Treatment with ultrasound provided more significant hemoglobin/triglyceride ratios, indicative of more lipid aspirated per hemoglobin lost, and better preservation of vascular tissues as demonstrated by our perfusion studies. Treatment with the sheath showed a significantly lower hemoglobin release with a diminished volume infused into the subcutaneous space during the procedure.

Acetylcholinesterase↗

PubMed1997

Use of a screening RAST in a large neuro-otologic practice.

Evidence in the literature emphasizes the role of the immune system in disorders of the inner ear and eustachian tube. We initially investigated the presence of inhalant allergy in selected patients seen for otologic problems by means of a screening radioallergosorbent test (RAST), using either a microscreen or a limited antigen panel. This study analyzed the results of tests performed over a 2-year period on 186 patients seen by one of us (WLM) for treatment of vertigo (66%), tinnitus (63%), hearing loss (49%), aural fullness (48%), Meniere's quadrad (27%), balance disturbance other than true vertigo (21%), and eustachian tube dysfunction (4%). We found an incidence of immunoglobulin E-mediated hypersensitivity of nearly 40% in a patient population selected solely for neuro-otologic symptoms and not for sinonasal symptoms. This figure is more than double that quoted for the general population. We also found a surprisingly high incidence of mold antigen atopy in this selected population. Allergy can contribute to a number of otologic symptoms, including eustachian tube dysfunction, vertigo, tinnitus, hearing loss, aural fullness, and nonspecific balance disturbance. Allergy also has been emphasized as an etiologic factor in a portion of patients diagnosed with Meniere's syndrome. A screening RAST, combined with clinical evaluation, appears to be an excellent tool for evaluating these patients for inhalant allergy as part of a comprehensive workup.

Adolescent↗

PubMed1997

Prevention of flash fires during facial surgery performed under local anesthesia.

As more surgical procedures are being performed under local anesthesia and intravenous sedation, complications associated with these techniques are more likely to be experienced. We report a case of an intraoperative flash fire that occurred while supplemental oxygen was being used in this scenario. A literature review and suggestions for prevention of this complication are discussed.

Accidents↗