Selective pressurized liquid extraction technique for halogenated organic pollutants in marine mammal blubber: a lipid-rich matrix.

Analytical methods for unique and rare samples, such as marine mammal tissue, strive to reduce opportunities for analyte loss and contamination. Historically, analytical methodologies for marine mammal tissues required an extraction followed by multiple cleanup and concentration steps. These steps increase the opportunity for analyte loss and sample contamination. Selective pressurized liquid extractions (SPLE; an analytical technique that combines PLE with in-cell adsorbent cleanup) have the potential to reduce and/or eliminate the number of steps. A SPLE method was developed for the simultaneous extraction of polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs) from bowhead whale blubber. This SPLE utilized acidic silica with a fat-to-fat retainer ratio of 0.02 as well as eliminated post-extraction cleanup steps, such as size-exclusion chromatography step. In addition, neutral silica was placed beneath the acidic silica as an acid buffer, thereby preventing acid from contaminating the extraction system. Analysis was performed using gas chromatography/mass spectrometry in electron capture negative ionization mode. PBDE, PCB and OCP triplicate recoveries averaged 84±1%, 83±3%, and 76±11%, respectively. Overall, measurements of NIST Whale Blubber SRM 1945 were within±30% of certified values. PBDEs were measured for the first time in bowhead whale blubber; average concentrations ranged from 0.2 to 1.4 ng g(-1) wet weight (ww). Average OCPs and PCBs concentrations ranged from 0.4 to 37 ng g(-1)ww and 0.1 to 3.0 ng g(-1)ww, respectively, which were within one order of magnitude lower than those previously reported in bowhead whale blubber.

Body and blubber relationships in antarctic pack ice seals: implications for blubber depth patterns.

Morphometrics and blubber depths from all four high Antarctic seals (Weddell, Ross, crabeater, and leopard) were obtained during a midsummer research cruise in the Ross Sea as the physiological ecology component of the U.S. Antarctic Pack Ice Seals project. These data are the only in vivo measurements of all four species from the same location and time of year and focused on variances in morphometrics and blubber depth related to species, sex, and age. By controlling for location and season, this cross-species design provided the means to differentiate how blubber mass might be influenced in these groups. We measured both absolute blubber depth and ratio of blubber depth to body core diameter. We found that adult and younger animals showed differences in blubber depth, but male versus female seals did not show differences within any given species. However, when compared across species, the ratio of blubber ring depth to body core diameter suggests that adult Weddell seals differ in their use of blubber compared with the other three species. We propose that this difference in blubber pattern is most likely related to Weddell nutritional requirements during the breeding season having a greater influence on blubber depth than thermal requirements when compared with the other three species.

The ontogeny of aerobic and diving capacity in the skeletal muscles of Weddell seals.

Our objective was to determine the ontogenetic changes in the skeletal muscles of Weddell seals that transform a non-diving pup into an elite diving adult. Muscle biopsies were collected from pups, juveniles and adults and analyzed for changes in fiber type, mitochondrial density, myoglobin concentrations and aerobic, lipolytic and anaerobic enzyme activities. The fiber type results demonstrated a decrease in slow-twitch oxidative (Type I) fibers and a significant increase in fast-twitch oxidative (Type IIA) fibers as the animals mature. In addition, the volume density of mitochondria and the activity of lipolytic enzymes significantly decreased as the seals matured. To our knowledge, this is the first quantitative account describing a decrease in aerobic fibers shifting towards an increase in fast-twitch oxidative fibers with a significant decrease in mitochondrial density as animals mature. These differences in the muscle physiology of Weddell seals are potentially due to their three very distinct stages of life history: non-diving pup, novice diving juvenile, and elite deep diving adult. During the first few weeks of life, pups are a non-diving terrestrial mammal that must rely on lanugo (natal fur) for thermoregulation in the harsh conditions of Antarctica. The increased aerobic capacity of pups, associated with increased mitochondrial volumes, acts to provide additional thermogenesis. As these future elite divers mature, their skeletal muscles transform to a more sedentary state in order to maintain the low levels of aerobic metabolism associated with long-duration diving.

Digestive constraints on an aquatic carnivore: effects of feeding frequency and prey composition on harbor seals.

We hypothesized that increased feeding frequency in captive harbor seals would increase nutrient loads and thus reduce retention time and the digestive efficiency of natural prey. We measured daily feed intake and excretion during 6 feeding trials and fed herring (49% lipid), pollock (22% lipid) or an equal mix of each diet over 24 months. Animals were accustomed to feeding at either high or low frequency. Body mass and intake did not vary with season. Although mean retention times were similar between diets and feeding frequencies, solute and particulate digesta markers separated at high feeding frequency. Consistent dry matter digestibility resulted in greater gut fill from pollock than from herring. Digestible energy intakes from pollock were approximately 25% greater than from either herring or the mixed diet. Lipid digestibility of herring declined from 90% to 50% when lipid intake exceeded 60 g kg(-0.75) day(-1). Our hypothesis of a trade-off between intake and digestion was not supported for protein but was supported for lipid. Results of this study imply that a flexible digestive system for harbor seals can compensate for ingesting prey of lower energy density by increasing gut fill and enhancing protein and lipid assimilation, to sustain digestible energy intake.

The periacetabular osteotomy. Minimum 2 year followup in more than 100 hips.

The results of 123 periacetabular osteotomies in 115 patients were reviewed at an average clinical followup of 4.3 years. The average age of the patients at the time of the operation was 32.9 years. The preoperative diagnosis was congenital dysplasia in 101 hips, Legg-Calve-Perthes disease in 10 hips, Charcot Marie Tooth disease in four hips, epiphyseal dysplasia in three hips, congenital coxa vara in two hips, slipped capital femoral epiphysis in one hip, and posttraumatic and postinfectious dysplasia in one hip each. The ilioinguinal approach was used in 67 hips and the modified Smith-Petersen approach was used in 56 hips. A periacetabular osteotomy was combined with an intertrochanteric osteotomy and/or trochanteric transfer in 32 hips. Ten hips underwent open reduction and internal fixation of an acetabular rim fracture and 18 arthrotomies were performed at the time of periacetabular osteotomy. The average Harris hip score increased from 65 points preoperatively to 89 points at latest followup. The average Merle d'Aubigne score increased from 13.6 points preoperatively to 16.3 points at latest followup. Overall, 83% of the hips were rated clinically as good to excellent. Seven hips have undergone total hip arthroplasty and six subsequent intertrochanteric osteotomies were performed. The majority of the major complications occurred when the osteotomy was performed through the ilioinguinal approach. The latest followup radiographic severity of osteoarthrosis, according to the criteria of Tönnis, improved or was unchanged in 117 hips (95%), and progressed in only six hips (5%). The majority of the hips with preoperative changes in the periarticular bone showed some evidence of regeneration, which was shown by a decrease in the subchondral sclerosis, disappearance of cysts, or healing of an acetabular rim fracture. The short term results of the periacetabular osteotomy are encouraging from the standpoint of improvements in clinical scores and in the appearance of the joint.

Results of periacetabular osteotomy in patients with previous surgery for hip dysplasia.

The results of 19 periacetabular osteotomies in 18 patients who had undergone prior bony surgical procedures for hip dysplasia were evaluated. There were 10 females and eight males with an average age of 30.9 years. Previous surgical interventions included 18 intertrochanteric osteotomies, nine pelvic osteotomies, and two shelf acetabuloplasties. The average clinical followup for this group was 45 months. Harris hip score averages improved from 60 to 90 points. Merle d'Aubigne scores showed similar elevations from 13.1 to 16.4 points. Radiographic assessment documented increased coverage and lower Tönnis secondary arthrosis grades in a significant number of hips. No significant differences in outcome were found between this group and a reference group of patients undergoing periacetabular osteotomy who had no previous hip surgery. These intermediate term results are encouraging and seem to discount anticipated problems of prior scarring and distorted pelvic and proximal femoral anatomy.

Proteins bound to polyethylene components in patients who have aseptic loosening after total joint arthroplasty. A preliminary report.

BACKGROUND: Immunological responses to proteins that adhere to ultra-high molecular weight polyethylene have not, to our knowledge, been examined previously in patients who have aseptic loosening. In the current study, polyethylene components from forty-nine failed prostheses recovered during revision procedures were examined for the presence of antibodies that were bound to the polyethylene surface or that were reactive with other proteins that were bound to the polyethylene surface. METHODS: The polyethylene components consisted of thirty acetabular cups recovered during revision total hip arthroplasties and nineteen tibial components recovered during revision total knee arthroplasties. After extensive washing, bound proteins were extracted from the polyethylene components with use of 0.1-molar glycine-hydrogen chloride solution followed by four-molar guanidine hydrochloride solution. RESULTS: Sufficient protein for analysis was recovered from forty-two polyethylene components. Polyacrylamide gel electrophoresis demonstrated a minimum of one and a maximum of twelve protein bands, with molecular weights ranging from thirteen to 231 kilodaltons. Immunoblotting revealed the presence of type-I collagen in most (thirty-four) of the forty-two explants, whereas aggrecan proteoglycans were detected in eight samples. Immunoglobulin also was detected in most (thirty-three) extracts, whereas type-II collagen was consistently absent. The presence of autologous antibodies directed against polyethylene-bound proteins in sera drawn at the time of the revision was investigated. Antibodies that were reactive against the ultra-high molecular weight polyethylene-bound proteins were detected in twenty-six of the forty-two patients with use of the Western blot technique. The number of reactive bands ranged from one to six, and the strongest binding was directed against a 103-kilodalton protein. Assays for specificity revealed that these sera autologous antibodies were reactive against the type-I collagen that was present in the explant solutions. CONCLUSIONS: We hypothesize that immunoglobulin complexed with polyethylene may fix complement and that the complement cascade may in turn attract inflammatory cells to the polyethylene surface. Our data support the hypothesis that an immunological response to antigens bound to the polyethylene surface may contribute to aseptic loosening. CLINICAL RELEVANCE: Despite improvements in materials and designs of prostheses, aseptic loosening is the most common complication of total joint replacement, frequently leading to revision operations. We examined the immunological response to proteins that bind to ultra-high molecular weight polyethylene in patients who had aseptic loosening and discovered a high prevalence of antibodies to polyethylene-bound proteins. This immunological response may contribute to an inflammatory reaction in the periprosthetic tissue, ultimately leading to increased bone resorption around the prosthesis.

Depression of the medial tibial plateau in early-onset Blount disease: myth or reality?

Patients with severe early-onset Blount disease (Langenskiold III or greater) often have the radiographic appearance of depression of the medial tibial plateau and delayed ossification of the epiphysis, adjacent physis, and metaphysis. Schoenecker and other authors recommended elevation of the medial plateau of the tibia for correction of this deformity. The purpose of this study was to assess the nature of the medial proximal tibia in these severe cases. Eight girls and two boys (17 tibiae) with severe early-onset Blount disease had standing radiographs and magnetic resonance imaging (MRI) evaluation. Average patient age was 5.8 years (range, 3-8 years). Eleven knees in eight patients underwent arthrography at the time of surgical correction of deformity. No tibia had MRI or arthrographic evidence of medial tibial joint "depression." The "empty" radiographic space was occupied by cartilage-density material. A smooth dye contour without pooling parallel to the femoral condyles was noted arthrographically in all instances. These findings do not support the concept of routine joint elevation in the correction of severe deformity associated with early-onset Blount disease.

Dementia in Down syndrome. Untangling the threads.

Despite frequent neuropathological findings, the prevalence of dementia in people with Down syndrome is thought to be no higher than in the general population. The age of onset, however, is approximately two decades earlier. The most important factor in the general practitioner's assessment of a person with this syndrome who appears to be dementing is the exclusion of medical problems that may be masquerading as Alzheimer disease. This article presents an efficient system for the clinical review of people with Down syndrome who are declining in function. The system is also adaptable for use with people who do not have this syndrome.

Metabolism of 2-aminofluorene by human polymorphonuclear leukocytes: more evidence for the association between inflammation and cancer.

Recent investigations have demonstrated the ability of leukocytes to metabolize promutagens or procarcinogens into their genotoxic forms. As a possible explanation for the association between inflammation and cancer, we and others have hypothesized that local accumulations of leukocytes could take up nearby promutagens, metabolize them, and release genotoxic agents that may cause damage in the surrounding tissue. Using a modified, two-step preincubation protocol with Salmonella, we have tested this hypothesis. We have shown that total human peripheral blood leukocytes, cultured in the presence of 2-aminofluorene for 18 hr, can metabolize 2-aminofluorene into agents mutagenic to Salmonella typhimurium strain TA98. Furthermore, experiments in which polymorphonuclear leukocytes were separated from mononuclear leukocytes demonstrated that the PMNs metabolized 2-aminofluorene to a much greater extent than the MNs.

Communicating with people who have intellectual disabilities.

Much of the art of general practice lies in the ability to communicate. For this reason, successful general practitioners tend to have highly developed skills in listening and talking to their patients. The process, however, becomes more difficult when patients do not share these verbal skills. The worldwide move towards the reintegration of previously institutionalised people means that most Australian general practitioners will encounter more intellectually disabled people in their practices. This accessing of mainstream health services appears to result in better quality care being available to this previously neglected group, although many people with intellectual disabilities report frustration in communicating effectively with their general practitioners.

Advocacy, guardianship and the GP.

Australians have come to realise that they have a right to access high quality health care through their general practitioner. It is essential that people with cognitive impairments through intellectual disability, psychiatric disorders, senility or brain damage are not denied equity of access through their inability to seek medical attention. Those who cannot make reasonable decisions or who cannot understand and give legal consent to operative procedures may need to have a guardian appointed to protect their rights. In other situations an advocate may be appointed if the person's rights are in jeopardy. The general practitioner is often the first person to become aware of the needs of disabled people and is well placed to intervene to ensure the protection of their rights. This includes the right to good health care.

Fluorescent histochemical localization of lipid peroxidation during brain reperfusion following cardiac arrest.

Rats were subjected to cardiac arrest and resuscitation, 90 min of reperfusion, and in situ perfusion fixation. Thiobarbituric acid (TBA) was included in the aldehyde-free perfusion fixative, the TBA reaction was driven in situ by heating, and fluorescence microscopy was utilized to characterize the location of products of the TBA reaction. Absorbance-difference spectra were performed on butanol-extracted brain homogenates to confirm in situ formation of TBA adducts with aldehydic products of lipid peroxidation. Nissl-stained sections revealed good cellular fixation without shrinkage artifacts. Fluorescence was not seen microscopically when TBA was omitted from the perfusion fixative, and little fluorescence was present in normal brains or brains after ischemia only. However, after 90-min reperfusion, intense granular fluorescence was seen in the neuronal perikarya (especially at the base of the apical dendrite) of numerous pyramidal neurons in cortical layers 5 and 6 and in the pyramidal layer of Ammon's horn in the hippocampus. The nuclei of these cells exhibited no fluorescence. Fluorescence was also present in some striatal neurons, but was absent in the adjacent radial bundles. Neither glia nor white matter exhibited similar fluorescence. These observations indicate that neurons in the selectively vulnerable zones of the cortex and hippocampus are early and specific targets of lipid peroxidation during post-ischemic reperfusion.

Hearing loss in the elderly. A survey in general practice.

OBJECTIVE: To determine the prevalence of undiagnosed hearing impairment in people aged 60 years or over in a general practice setting. DESIGN: A self-administered questionnaire followed by physical examination and audiometry. SETTING: A group general practice in the Melbourne suburb of Moorabbin. PATIENTS: Two hundred and one people aged 60 years or over who were not known to be hearing impaired. OUTCOME MEASURE: Results of air-conduction audiometry. RESULTS: Seventy-five of the 201 people had undiagnosed hearing loss (37%). The assessments of hearing ability by the patients and their relations were good predictors of the outcome of the audiogram (P < 0.001). Occupational history, medical history and physical examination were poor predictors (P > 0.05). CONCLUSIONS: The use of audiometry for screening for hearing impairment in older general practice patients is likely to have a high yield. A large proportion of people with abnormal audiograms will, however, refuse a hearing aid.