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Biomedical subjects

M H Cooper

Publications and source records attributed to M H Cooper.

At least 19 recordsLinked to original sources
PubMed2001

Comparison of the Bligh and Dyer and Folch methods for total lipid determination in a broad range of marine tissue.

For many studies, it is important to measure the total lipid content of biological samples accurately. The Bligh and Dyer method of extraction was developed as a rapid but effective method for determining total lipid content in fish muscle. However, it is also widely used in studies measuring total lipid content of whole fish and other tissues. Although some investigators may have used modified Bligh and Dyer procedures, rarely have modifications been specified nor has their effectiveness been quantitatively evaluated. Thus, we compared this method with that of the classic Folch extraction in determining total lipid content of fish samples ranging from 0.5 to 26.6% lipid. We performed both methods as originally specified, i.e., using the chloroform/methanol/water ratios of 1:2:0.8 and 2:2:1.8 (before and after dilution, respectively) for Bligh and Dyer and of 8:4:3 for Folch, and with the initial solvent/sample ratios of (3+1):1 (Bligh and Dyer) and 20:1 (Folch). We also compared these with several other solvent/sample ratios. In samples containing <2% lipid, the results of the two methods did not differ. However, for samples containing >2% lipid, the Bligh and Dyer method produced significantly lower estimates of lipid content, and this underestimation increased significantly with increasing lipid content of the sample. In the highest lipid samples, lipid content was underestimated by up to 50% using the Bligh and Dyer method. However, we found a highly significant linear relationship between the two methods, which will permit the correction of reported lipid levels in samples previously analyzed using an unmodified Bligh and Dyer extraction. In the future, modifications to procedures and solvent/sample ratios should be described.

Animals↗
PubMed1998

Comparison of subperiosteal vs subgaleal elevation techniques used in forehead lifts.

OBJECTIVES: To compare eyebrow and forehead elevation and tension among the following 3 surgical techniques: subperiosteal dissection to the supraorbital rim, subperiosteal dissection with release (elevation, incision, and spread) of periosteum at the supraorbital rim, and subgaleal dissection to the supraorbital rim, and to determine the optimal method of elevation in an aesthetically accepted range for the endoscopic forehead lift. DESIGN: A randomized, self-controlled study using an open approach to the forehead in cadaver heads. Each half of head was compared with the other in the following 2 study groups: subperiosteal dissection without release vs subperiosteal dissection with release of periosteum (group 1) and subperiosteal dissection with release of periosteum vs subgaleal dissection. SETTING: Anatomy laboratory at a university medical center. SUBJECTS: Eight cadaver heads fixed with ethylene glycol in each group. INTERVENTION: Predissection distances in millimeters from fixed anatomic landmarks were measured. The forehead flaps were elevated using a coronal incision and divided with a midline incision for side-to-side comparison. Cadaver heads and side of surgical intervention were selected randomly. The flap tensions associated with incremental flap advancement of 0.5 and 1.0 cm were measured. Traction of 2.2 kg was then applied to each flap, and distances between the fixed landmarks were measured. MAIN OUTCOME MEASURES: Mean predissection and postdissection distance of brow and forehead elevation for each dissection type and mean distance and median tension of brow and forehead elevation within each group. RESULTS: The mean postdissection brow measurements at rest were significantly greater than the mean predissection measurements at most landmarks in all dissections for both groups (P<.05). The mean postdissection brow and forehead measurements with 2.2 kg of traction were significantly greater than the mean predissection measurements at all landmarks in all dissections for both groups (P<.05). The mean increase in distance from predissection to postdissection (at rest and with 2.2 kg of traction) did not significantly differ between the different dissection types (P>.05). For group 1, the median flap tension for subperiosteal dissection without release was greater than that for subperiosteal dissection with release (P>.05). For group 2, subperiosteal dissection with release had greater median flap tension than subgaleal dissection (P>.05). CONCLUSIONS: All 3 methods of dissection significantly elevated the brow at rest for most landmarks. All 3 methods of dissection significantly elevated the brow and forehead when traction was applied to the flap. Brow and forehead elevation at rest and with 2.2 kg of traction did not significantly differ between the dissections. Subgaleal dissection was associated with less flap tension compared with the subperiosteal dissection with or without release. The data support the use of all 3 methods of forehead dissection for brow elevation and subgaleal forehead dissection as the optimal approach for the forehead lift, whether performed endoscopically or open.

Aged↗
PubMed1997

Clinical and histologic response of subcutaneous expanded polytetrafluoroethylene (Gore-Tex) and porous high-density polyethylene (Medpor) implants to acute and early infection.

OBJECTIVE: To examine the responses of subcutaneously implanted expanded polytetrafluoroethylene (e-PTFE, Gore-Tex) and porous high-density polyethylene (PHDPE, Medpor) to experimentally induced infection. DESIGN: Sprague-Dawley rats were implanted subcutaneously with either e-PTFE or PHDPE implants. Inocula of Staphylococcus aureus were injected directly over the implants and the wounds were observed for clinical signs of infection. After the animals were killed, the implants were harvested and underwent Histologic examination. SUBJECTS: Twenty-eight adult male Sprague-Dawley rats weighing 200 to 250 g. INTERVENTION: A 8-mm diameter, 1-mm-thick implant of either e-PTFE or PHDPE was placed in a subcutaneous pocket over each animal's dorsum. Either at the time of implantation or 14 days afterward, an inoculum of 10(9) colony-forming units of S aureus was injected transcutaneously directly over each implant. The animals were observed for 7 days before being killed. The implants were harvested and examined by both conventional light and scanning electron microscopy, and the degree of capsule reaction, infection, inflammation, and implant degradation was evaluated. RESULTS: Implants inoculated at the time of implantation were more likely to become clinically infected. Results for e-PTFE and PHDPE implants were similar in this group (5 of 5 e-PTFE and 5 of 5 PHDPE implants infected). The PHDPE implants inoculated 14 days after implantation were less likely to become infected (1 of 4 infected) than e-PTFE implants (3 of 4 infected), and were statistically less likely to become infected than PHDPE implants inoculated immediately after implantation (25% vs 100%; P < .02). Histologically, this resistance to infection correlated with increasing fibrovascular ingrowth into the PHDPE implants. The infected PHDPE implant had little to no ingrowth compared with PHDPE control implants. The uninfected e-PTFE implant had evidence of early fibrovascular ingrowth into the peripheral pores of the implant. CONCLUSIONS: Because of differences in pore size, PHDPE promotes faster fibrovascular ingrowth. The presence of vascularized host tissue in and around the implant lends stability and resistance to experimentally induced infection. Conservative management of clinical implant infections should be considered if bacterial seeding occurs after substantial fibrovascular ingrowth is present. Future alloplast designs should include pore sizes that will encourage invasion of the implant by host tissue.

Animals↗
PubMed1995

Core services and the New Zealand health reforms.

The last 5 years have seen dramatic changes in health care provision in New Zealand. Amidst considerable controversy, the 14 Area Health Boards were abolished in July 1993. The State now funds 4 Regional Health Authorities (still on the basis of a weighted population formula) from Vote Health (the health sector's share of public expenditure). The role of the National Advisory Committee on Core Health and Disability Support Services and other bodies in determining the annual policy and service obligations faced by the 4 Regional Health Authorities is discussed.

Health Care Rationing↗
PubMed1994

Rapamycin but not FK506 inhibits the proliferation of mononuclear phagocytes induced by colony-stimulating factors.

FK506, CsA, and rapamycin are potent inhibitors of T lymphocyte activation; relatively little is known of their effects on cells of the monocyte/macrophage lineage. Studies were undertaken to determine the effects of these drugs on the proliferative response of bone marrow-derived mononuclear phagocytes (BMMP) to CSFs. Rapamycin inhibited the proliferation of BMMP cultured in the presence of 10% L cell-conditioned medium, used as a source of macrophage CSF. The inhibition by rapamycin was dose dependent and apparent at concentrations of 0.1 nM or greater. In a similar fashion, rapamycin inhibited the proliferation of BMMP stimulated by the recombinant forms of murine IL-3 and murine granulocyte-macrophage CSF, and human macrophage CSF. In contrast, neither FK506 nor CsA at concentrations as high as 1000 nM diminished the proliferation of BMMP cultured under identical conditions. FK506, but not CsA, blocked the inhibitory effects of rapamycin on the response of BMMP to CSFs. In summary, these data indicate that rapamycin inhibits the proliferation of BMMP in response to CSFs. These results imply that patients receiving rapamycin, but not FK506 or CsA, may have an impaired ability to generate a functional mononuclear phagocyte population.

Animals↗
PubMed1994

Short-term myeloid reconstitution following TBI is not adversely affected by doses of FK506 that abrogate lethal GVHD.

Studies were undertaken to determine whether the doses of FK506 that are effective for acute GVHD prophylaxis following lethal irradiation and bone marrow transplantation (BMT) would also suppress myeloid cell reconstitution. FK506 (3 mg/kg/day) abrogated acute lethal graft versus host disease (GVHD) in lethally irradiated C57BL/10SnJ (H-2b) recipient mice given histoincompatible BM plus spleen cells from B10.BR (H-2k) donors and this dose was used in all of the studies. Endogenous and exogenous myeloid repopulation was studied in mice given daily injections of either FK506, an equivalent amount of carrier solvent or no treatment throughout the interval between total body irradiation (TBI) and the day of assay. Repopulation was studied after 400 or 500 cGy TBI (endogenous) and after 950 cGy TBI plus injection with syngeneic BM (exogenous). No consistent adverse effects of FK506 were seen during either exogenous or endogenous recovery. Parameters studied included hematocrit (Hct), WBC count, cells per humerus, spleen weight, splenic colony-forming units, % spleen or BM 59Fe uptake and colony forming cells per humerus. Similarly, when lethally irradiated secondary recipients were reconstituted with BM from FK506 treated primary recipients (lethal irradiation plus exogenous BM), no consistent effects were observed. These data suggest that FK506 given to prevent GVHD would not compromise the myeloid recovery that is critical for survival in the interval of time following shortly after BMT.

Animals↗
PubMed1993

Cross-species graft-versus-host-disease is accompanied by a donor-derived cellular immune response.

Acute graft-versus-host-disease is classically described as reactivity of donor lymphocytes to recipient alloantigens. To date there is debate as to whether GVHD can be induced across a species barrier. We recently reported the induction of stable xenogeneic chimerism (rat-->mouse) and donor-specific transplantation tolerance using the transplantation of untreated rat bone marrow cells into B10 mouse recipients. Survival of chimeras was excellent, and there was no evidence of GVHD. We now describe the induction of xenogeneic GVHD by transplanting large numbers of donor rat spleen cells with the bone marrow inoculum. All chimeras that received bone marrow and untreated spleen cells developed an external appearance compatible with GVHD and had a median survival time of 14 days. Mice that received equivalent numbers of untreated rat bone marrow alone appeared healthy, had no evidence for GVHD, and survived > 90 days. The usual epithelial target tissues for allogeneic GVHD in those mice that received xenogeneic bone marrow and spleen cells showed the presence of tissue injury and histologic features compatible with GVHD. Donor rat MHC class I and class II positive cells were prominent cell types present in the tongues of mice that developed features of GVHD, and this was accompanied by a significant inflammatory tissue response with loss of the dermal-epidermal architecture. In contrast, fully xenogeneic chimeras without GVHD had no evidence for tissue injury or pathologic cellular infiltrates when examined by immunohistochemical analysis. These data suggest that although fully xenogeneic chimeras resist GVHD, GVHD can be induced across a species barrier if sufficient numbers of donor rat spleen cells are added to the bone marrow inoculum. Further comparisons of these models may provide an approach to study the mechanisms responsible for xenoreactivity in vivo.

Animals↗
PubMed1993

HIV infection in autologous and allogeneic bone marrow transplant patients: a retrospective analysis of the Marseille bone marrow transplant population.

Twelve HIV-positive patients who either underwent or seroconverted after bone marrow transplantation (BMT) at the University of Marseille between 1981 and 1985 were reviewed in order to observe their rates of development of AIDS. Two patients were HIV positive prior to transplantation, while ten seroconverted after transplantation. Six patients underwent autologous BMT and six underwent allogeneic BMT; all of their respective donors were seronegative. Eleven patients developed AIDS (92%), with a mean AIDS-free time (AFT) of 1 year 8 months after BMT. Seven of those subjects died, with a mean survival over a 5-year follow-up period of 2.14 years after BMT. Five autologous recipients had a mean AFT of 2 years 3 months, with the sixth patient being AIDS free. The mean AFT for the allogeneic recipients was 1 year 2 months (p = NS), all of whom developed AIDS. These data suggest that the development of AIDS was rapid from the time when our patients seroconverted. However, this was not initially accompanied by poor survival. In summary, BMT may be indicated for HIV-positive patients who required myeloablation, despite an enhanced development of AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Anatomic importance of the retrofacial air tract.

The retrofacial air tract is a constant and relevant anatomic landmark for the temporal bone surgeon. By purposefully dissecting this space, one is able to safely identify the facial nerve, endolymphatic sac, and jugular bulb. The retrofacial air tract also provides access to the petrous apex. Forty temporal bones of varying degrees of pneumatization were dissected in order to study the retrofacial air tract. A well-developed air tract was easily identified in all specimens. We describe our anatomic findings and discuss the surgical relevance and important of the retrofacial air tract.

Ear, Inner↗
PubMed1991

Advances in non-invasive measures of vocal acoustics.

Objective assessment of vocal pitch, loudness, and quality is a crucial adjunct to endoscopy in the diagnosis and treatment of vocal pathology. Historically, this assessment was made through subjective, perceptual measures that were questionable in terms of validity and reliability. Recent advances in electronic technology now permit objective analysis of the acoustic characteristics of voice. Kay Elemetric's Visi-Pitch, DSP 5500 Digital Spectrograph, and Nasometer are representative of these new instruments and are used as illustrations in the discussion of the assessment of speech acoustics.

Humans↗
PubMed1991

Non-invasive assessment of phonatory and respiratory dynamics.

Evaluation of vocal pathology and the accompanying dysphonia should include an assessment of laryngeal structure and mobility as well as respiratory dynamics. Laryngeal structure is best observed through laryngoscopy which provides an accurate assessment of the tissues and their mobility. Respiratory measures of lung volume, air-flow and pressure, and breathing dynamics are typically determined via spirometry and pneumotachography. While the above are traditional invasive procedures which interfere with normal speech production, recent advances in electronic technology have resulted in the development of non-invasive procedures to assess phonatory and respiratory dynamics. These procedures, when used as an adjunct to laryngoscopy, can provide information that is useful in the diagnosis and management of vocal tract dysfunction. The Laryngograph and Computer-Aided Fluency Establishment Trainer, described here, are examples of this new technology.

Humans↗