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Biomedical subjects

J B Robinson

Publications and source records attributed to J B Robinson.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1998

The myoadipose flap: a new composite.

A prefabricated composite fat flap consisting of muscle woven into an anatomically distinct fat pad was studied in a rabbit model. In 17 rabbits, a 2-cm strip of latissimus dorsi was woven into the parascapular fat pad on one side, with the contralateral fat pad serving as a control. At 3 weeks, the endogenous blood supply of both the control and the experimental fat pads was isolated and ligated, and the composite fat/muscle flap was transferred to the chest wall. At 6 weeks, animals were killed, and flaps were analyzed for length, width, and weight; perfused with fluorescein or lead oxide; and examined histologically. Significant differences were found between the control and experimental fat pads with regard to weight and length. Experimental flaps were found to be perfused fully with fluorescein and lead oxide; control fat pads were found not to be perfused. The lead oxide group revealed extensive growth of blood vessels from the latissimus graft into the experimental fat pad. No vessels were visualized in the controls. Finally, sections of the control and experimental flaps were analyzed histologically. A preponderance of viable fat, with evidence of neovascularization, was found in experimental flaps, compared with the necrotic fat that characterized the controls. We conclude that prefabrication of a fat flap is possible and may have extensive application in various areas of plastic surgery.

Adipose Tissue↗
PubMed1998

An analysis of silicone gel-filled breast implants: diagnosis and failure rates.

This retrospective review analyzed 180 women who underwent explantation of 357 silicone gel-filled breast implants from September of 1991 to January of 1995. Implant status, including shell integrity and implantation times, was determined at the time of explantation. The age range of the patients was 25 to 75 years, with a mean age of 47 years. The age of the implants ranged from 0.5 to 24 years, with a mean age of 10.5 years. Of the 292 implants with known and documented integrity status, there were 102 intact, 76 unruptured with signs of leakage, and 114 ruptured. The frequency of implant rupture significantly increased with implant age. The average age of rupture was 13.4 years. The average age of signs of leakage was 10.1 years. There were no significant differences in failure rates among the implant types of four manufacturers. Analysis of both mammography and magnetic resonance imaging (MRI) as diagnostic modalities for differentiating intact implants, implant leakage, and implant rupture was performed. Standard mammography was less reliable in diagnosing implant leakage or rupture (sensitivity, 55 percent; specificity, 69 percent) than MRI (sensitivity, 72 percent; specificity, 82 percent). In conclusion, implant rupture occurred at a significantly increasing rate with implant age (10 to 15 years). These findings were independent of implant type or manufacturer. Mammography alone is a below-average diagnostic tool for detecting leakage or rupture, whereas MRI is a more accurate modality.

Breast Implants↗
PubMed1998

Characterization of chemotactic responses and flagella of Hyphomicrobium strain W1-1B.

Motile swarmer cells of Hyphomicrobium strain W1-1B displayed positive chemotactic responses toward methylamine, dimethylamine, and trimethylamine but did not display significant chemotactic responses towards methanol and arginine. Electron micrographs of negatively stained intact flagellar filaments indicated a novel striated surface pattern. The flagella were composed of two proteins of 39 and 41 kDa. Neither protein was a glycoprotein as determined by Schiff's staining and by enzyme immunoassay. Protein fingerprints visualized from silver-stained polyacrylamide gels and Western blots of protease-digested samples indicated that the two proteins were similar but not identical. Monoclonal antibodies prepared to the complex flagella of Rhizobium meliloti cross-reacted with the striated flagella of Hyphomicrobium strain W1-1B; however, these antibodies did not cross-react with smooth-surface flagella. These results suggest that complex and striated flagella possess homologous epitope regions.

Antibodies, Bacterial↗
PubMed1997

Cervical carcinoma metastatic to the brain.

Brain metastases from cervical cancer are uncommon and are usually considered incurable. Characterization of presentation and a consensus on standard effective treatment have not been published. We present a case in which long-term disease-free survival has been achieved by surgical resection of a solitary brain metastasis with postoperative whole brain radiation. The world literature is examined and discussed in relation to this experience.

Aged↗
PubMed1997

Phylogenetic and narG analysis of a Hyphomicrobium isolate.

An obligately methylotrophic organism was isolated from a water well that manifested symptoms of biofouling. The isolate was appendaged and utilized methylamine, dimethylamine, trimethylamine, or methanol as the sole carbon and energy source. The isolate exhibited hydroxypyruvate reductase activity, suggesting C1-assimilation via the serine pathway. Fatty acid profiling indicated the predominance of 18:1 cis-fatty acids. The isolate did not grow anaerobically with nitrate as the final electron acceptor. Genomic DNA from the isolate did not hybridize against the narG gene, which encodes the alpha subunit of dissimilatory nitrate reductase in Escherichia coli. The phenotypic data suggested the assignment of the isolate to the genus Hyphomicrobium. The identification was supported by phylogenetic characterization based on 16S rRNA sequence comparisons of the isolate.

Bacteria↗
PubMed1996

The effect of a muscle wrap on nerve healing in a rat model.

Sixty Sprague-Dawley rats were studied to determine if peripheral nerve healing could be enhanced by translocation of an injured segment of sciatic nerve from an interfascial to an intramuscular environment. Group 1 (n = 12) were unoperated controls; Group 2 (n = 12) were sham-operated; Group 3 (n = 12) sustained an acute, double-crush injury to the sciatic nerve; and Group 4 (n = 12) sustained the same acute, double-crush injury as in Group 3, but the injured segment of nerve was transposed intramuscularly. All animals had sciatic function indices (SFI) computed at weekly intervals. At 2 weeks, Group 4 appeared to have improved gait function (SFI), compared to Group 3 (-39.7 vs. -56.4, p < 0.08). The experiment was repeated for Groups 3 and 4 using two groups of six additional rats each. The data were collected three times for each rat in the second experiment. No statistically significant differences in return of gait function or in nerve conduction evaluation could be demonstrated between the two study groups. From the results of this study, it appears that an intramuscular location does not enhance nerve recovery, compared to an interfascial location.

Animals↗
PubMed1996

Determining the safety of the silicone envelope: in search of a silicone antibody.

In the controversy surrounding breast implants, one of the crucial questions is whether patients ca form antibodies directed against the silicone shell of the implant. If this were the case, implications for current breast implant development, indeed, for all silicone medical devices, are far-reaching. To evaluate this hypothesis, sera from 18 patients who had tissue expanders and 15 control patients who had no silicone implant exposure were tested retrospectively for antibodies to the silicone using an enzyme-linked immunosorbent assay previously documented as a case report in the literature. Contrary to previous studies, no significant difference in antibody levels was found between test subjects and the controls. Additionally, this enzyme-linked immunosorbent assay for silicone antibodies was poorly reproducible. This study calls into question the existence of specific antibodies to the silicone shell. It also provides further data that the enzyme-linked immunosorbent assay may not be reliable as a silicone antibody test.

Antibodies↗
PubMed1996

Saline made viscous with polyethylene glycol: a new alternate breast implant filler material.

Silicone shell implants filled with either saline or polyethylene glycol 20,000 at 85 percent weight/volume were placed subcutaneously on the dorsal aspect of 20 rabbits, and after 2 weeks, selected implants were ruptured by subcutaneous insertion of a hypodermic needle. After 6 weeks and 6 months, histologic analyses of tissue samples from both groups showed no deviation in any organ from the norm. Further physical and chemical experiments on these devices showed no contradiction to their use as potential alternative filler material for breast implants in plastic surgery.

Animals↗
PubMed1996

Disordered eating in female collegiate athletes and collegiate females in an advanced program of study: a preliminary investigation.

The purpose of this study was to use the Eating Disorders Inventory-2 (EDI-2) to compare disordered eating pathology between female intercollegiate athletes and a control group of nonathletic subjects enrolled in an advanced program of study. Analysis of variance (ANOVA) procedures revealed no significant difference (NSD) (p > .05) between any of the athletic groups or the control group on any EDI-2 subscale, and there was no significant difference between "lean" sports, other sports, and the control group. There was also NSD on EDI-2 subscale scores on the basis of age. African Americans had significantly lower scores on the Body Dissatisfaction and Impulse Regulation subscales than white Americans. Chi-square analysis revealed NSD between any groups in percentage of respondents scoring above anorexic norms. The results did not indicate a greater amount of disordered eating in female athletes compared to nonathlete controls.

Adolescent↗
PubMed1995

Effect of skin-graft harvesting on hair growth; implications for the study of alopecia.

An experiment using guinea pigs was performed to demonstrate the feasibility of repeated skin-graft harvesting as a model system in the study of diffuse alopecia. In response to four split-thickness skin harvests from the same site at 2-week intervals, the number of hairs observed and follicular area doubled, implying a transition of hair follicles from vellus to terminal, compared with ungrafted control skin from the alternate side of the same animals. The guinea pig may serve as a future model for the study of diffuse alopecia because its hair growth patterns are similar to those observed in humans.

Alopecia↗
PubMed1995

Fetal porcine vascular anatomy: clinical and research implications for fetal surgery.

Our understanding of fetal vascular anatomy is rudimentary. This article evaluates the rate of fetal vascular branch-point development at different gestational ages using a porcine model. The consistent biphasic, vascular branch-point development provides an improved understanding of fetal vascular anatomy, although further studies on fetal growth and the effects of anesthetic agents and vascular response to surgical techniques at the various gestational stages are needed. This will enhance fetal-maternal safety as the clinical use of fetal surgery broadens in the future.

Animals↗
PubMed1995

Irreversible inhibition of rat liver mitochondrial MAO A and MAO B by enantiomers of deprenyl and alpha-methylpargyline.

Using rat liver mitochondrial monoamine oxidase (MAO) A and MAO B, the possible influence of stereochemical factors upon the irreversible inhibition by propargylamine derivatives has been studied using the enantiomers of deprenyl and of alpha-methylpargyline. Whether studying the inhibition of MAO A or MAO B, little difference was found among enantiomeric pairs in the first-order rate constant (k2) for formation of the enzyme inhibitor adduct. Similarly, and with the exception of (S)-D-(+)-deprenyl (k2 = 0 or an extremely low value at MAO A), the computed value of k2 for the individual enantiomers showed little variation between MAO A and MAO B. These results suggest that inhibitor selectivity towards a particular form of the enzyme is determined predominantly at the competitive phase of the inhibition.

Animals↗
PubMed1995

Acute exertional rhabdomyolysis and its relationship to sickle cell trait.

Exertional rhabdomyolysis, a syndrome characterized by skeletal muscle degeneration and muscle enzyme leakage, has been shown to occur in normal, healthy individuals following strenuous exercise. In severe cases, this syndrome can result in renal failure and sudden death. Although anyone who performs strenuous exercise may be at risk for developing exertional rhabdomyolysis, some individuals may be more susceptible than others. A number of case reports of exertional rhabdomyolysis involve persons with sickle-cell trait, leading to the theory that these individuals might be at greater risk for developing the syndrome than those without this trait. This article discusses the etiology of exertional rhabdomyolysis, the associated risk factors for persons with sickle-cell trait, and the recommended preventive measures. Additionally, several case studies of exertional rhabdomyolysis are reviewed.

Journal Article↗
PubMed1995

Iloprost enhances survival of axial-pattern skin flaps in an ischemia-reperfusion model.

Iloprost, a stable prostacyclin analogue, significantly enhances the survival of an axial-pattern groin flap in rats after ischemia-reperfusion. Treated flaps showed viability over 90 percent of their area 7 days after an 8-hour ischemic episode, whereas the saline-treated controls were viable over only 20 percent of their area (p = 0.002). This effect was seen at a low (10 ng/kg) dosage, and no apparent side effects were noted.

Animals↗