Finite element predictions of cartilage contact mechanics in hips with retroverted acetabula.

BACKGROUND: A contributory factor to hip osteoarthritis (OA) is abnormal cartilage mechanics. Acetabular retroversion, a version deformity of the acetabulum, has been postulated to cause OA via decreased posterior contact area and increased posterior contact stress. Although cartilage mechanics cannot be measured directly in vivo to evaluate the causes of OA, they can be predicted using finite element (FE) modeling. OBJECTIVE: The objective of this study was to compare cartilage contact mechanics between hips with normal and retroverted acetabula using subject-specific FE modeling. METHODS: Twenty subjects were recruited and imaged: 10 with normal acetabula and 10 with retroverted acetabula. FE models were constructed using a validated protocol. Walking, stair ascent, stair descent and rising from a chair were simulated. Acetabular cartilage contact stress and contact area were compared between groups. RESULTS: Retroverted acetabula had superomedial cartilage contact patterns, while normal acetabula had widely distributed cartilage contact patterns. In the posterolateral acetabulum, average contact stress and contact area during walking and stair descent were 2.6-7.6 times larger in normal than retroverted acetabula (P ≤ 0.017). Conversely, in the superomedial acetabulum, peak contact stress during walking was 1.2-1.6 times larger in retroverted than normal acetabula (P ≤ 0.044). Further differences varied by region and activity. CONCLUSIONS: This study demonstrated superomedial contact patterns in retroverted acetabula vs widely distributed contact patterns in normal acetabula. Smaller posterolateral contact stress in retroverted acetabula than in normal acetabula suggests that increased posterior contact stress alone may not be the link between retroversion and OA.

Suppression of sleep-induced growth hormone secretion by anticholinergic agent abolishes dawn phenomenon.

The dawn phenomenon was evaluated in eight C-peptide-negative type I (insulin-dependent) diabetic patients on two occasions by measuring glucose concentrations every 30 min from 2400 to 0800 h while the subjects were receiving an insulin infusion (0.12 mU.kg-1.min-1). In random order at 2230 h, they orally received either a sleeping medication alone or with 5.0 mg methscopolamine bromide, an anticholinergic agent. The peak growth hormone (GH) concentrations (ng/ml +/- SE) after sleep were markedly inhibited by methscopolamine (4.7 +/- 2.6 vs. 23.0 +/- 9.2). During the control night, the late (0400-0800 h) glucose response (area under curve but above 0400 h value) was significantly higher (P less than .02) than the early (2400-0400 h) glucose response (area under curve but above 2400 h value). After methscopolamine, the early and late glucose responses were virtually identical. The anticholinergic agent did not affect glucagon levels, overnight urinary catecholamine excretion, or the diurnal cortisol concentrations. The total area under the free fatty acid (FFA) curves was significantly (P less than .05) reduced by methscopolamine. We conclude that sleep-induced GH secretion may cause the dawn phenomenon by increasing FFA levels. Oral administration of methscopolamine at bedtime is a simple pharmacological approach that could test the clinical importance of the dawn phenomenon.

Simple solution to problem of biostator-induced insulin aggregation.

It has recently been reported that there is a significant loss of insulin immunoreactivity and bioavailability secondary to heat-induced insulin aggregation during prolonged insulin delivery by the Biostator. This artifact of Biostator insulin delivery system makes data generated by studies that use prolonged, continuous insulin infusions performed with the Biostator uninterpretable. We report the prevention of this problem by the addition of 20 ml heparinized whole blood to a 500-ml reservoir containing the insulin to be infused. The proposed solution is simple, economical, and without risk to the subject since his or her own blood can be used.

Insulin antagonism is not a primary abnormality of amyotrophic lateral sclerois but is related to disease severity.

Sensitivity to insulin was studied in 13 patients with amyotrophic lateral sclerosis (ALS) and 10 age- and weight-matched normal subjects by performing euglycemic clamp studies at low (1.5 mU/kg X min) and high (10 mU/kg X min) insulin infusion rates. Mean glucose disposal rates were similar in the ALS patients and normal subjects at both the low [4.8 +/- 0.6 (+/- SEM) vs. 5.2 +/- 0.6 mg/kg X min] and high (9.2 +/- 1.3 vs. 9.8 +/- 0.5 mg/kg X min) insulin infusion rates, respectively. Binding of [125I] iodoinsulin to monocytes was also similar in seven patients with ALS (3.8 +/- 1.0%/10(7) cells) and 10 normal subjects (3.9 +/- 0.9). However, glucose disposal rates correlated inversely with disease severity in the ALS patients, at both the low (r = -0.76; P less than 0.01) and high (r = -0.83; P less than 0.001) insulin infusion rates. We conclude that insulin antagonism is not a primary abnormality of ALS, but may be related to the inactivity associated with disease progression.

Effect of in vitro generation of oxygen free radicals on T cell function in young and old rats.

T cells from young (6 months) and old (24 months) male Fischer 344 rats were isolated and exposed to three different oxidative stress conditions: (a) reactive oxygen species generated by xanthine-xanthine oxidase (X/XO), (b) hydrogen peroxide (H2O2), and (c) hyperthermia (43 degrees C for 1 h). After oxidative stress treatment, the induction of proliferation and IL-2 production by concanavalin A (Con A) was measured. Exposure of T cells to X/XO or H2O2 resulted in suppression of proliferation and IL-2 expression, and the suppressive effect was more pronounced in T cells from young rats than in T cells from old rats. Similarly, hyperthermia caused inhibition of proliferation and IL-2 expression in T cells from young and old rats. Addition of antioxidant to cultured cells only slightly attenuated the effects of X/XO and H2O2 on T cell function; however, antioxidant had no effect on heat shock-mediated inhibition of proliferation in young or old rats. Because IL-2 plays a crucial role in T cell proliferation and because the transcription factor NFAT (nuclear factor of activated T cell) plays a major role in the regulation of IL-2 transcription, the induction of NFAT as well as NF-KB and AP-1 DNA binding activities in nuclear extracts of the X/XO-treated and untreated control cells was measured using a gel shift assay. The ability of nuclear extracts to bind NFAT or NF-KB oligonucleotide decreased in the X/XO-treated cells from young and old rats compared to the untreated controls. Therefore, these data imply that reactive oxygen species generated by the X/XO system alter the distal step of mitogen-mediated signal transduction, i.e., transcription factors that regulate IL-2 transcription.

Idiopathic fasting hypoglycemia in an adult.

A 73-year-old man with documented and persistent fasting hypoglycemia for at least 22 years underwent extensive study including percutaneous liver biopsy for measurement of selected enzymes. No known cause of fasting hypoglycemia could be found. This is believed to be the first reported case of "idiopathic" fasting hypoglycemia in an adult. At the present time, it is not possible to classify the cause of this patient's hypoglycemia due to incomplete understanding of the abnormalities of carbohydrate metabolism.

Effect of dehydroepiandrosterone on mitogen-induced lymphocyte proliferation and cytokine production in young and old F344 rats.

The steroid hormone intermediate, dehydroepiandrosterone (DHEA), has been proposed as a therapeutic agent for the treatment of immunosenescence in mouse model. In the present study, the in vitro effect of DHEA on mitogen-induced lymphocyte proliferation and cytokine production was evaluated in a rat model. Spleen lymphocytes were isolated from young (4-6 months) and old (24-26 months) F344 rats and were incubated with DHEA for 30 min. The induction of lymphocyte proliferation, interleukin-2 (IL-2), and interferon-gamma (IFN-gamma) production by concanavalin A (Con A) was measured in a culture medium supplemented with either fetal calf serum (FCS) or with serum-free medium (Nutridoma-SR, N-SR). The induction of lymphocyte proliferation and IL-2 production by Con A decreased significantly with age, whereas induction of IFN-gamma increased with age. Treatment of lymphocytes with DHEA did not significantly alter Con A-induced proliferation or the production of IL-2 or IFN-gamma by spleen lymphocytes isolated from either young or old rats. These data indicate that in vitro DHEA treatment appears to have no immunomodulatory effect on the age-related changes in mitogen-induced proliferation or cytokine production in rat lymphocytes.

Coastal freshwater runoff is a risk factor for Toxoplasma gondii infection of southern sea otters (Enhydra lutris nereis).

The association among anthropogenic environmental disturbance, pathogen pollution and the emergence of infectious diseases in wildlife has been postulated, but not always well supported by epidemiologic data. Specific evidence of coastal contamination of the marine ecosystem with the zoonotic protozoan parasite, Toxoplasma gondii, and extensive infection of southern sea otters (Enhydra lutris nereis) along the California coast was documented by this study. To investigate the extent of exposure and factors contributing to the apparent emergence of T. gondii in southern sea otters, we compiled environmental, demographic and serological data from 223 live and dead sea otters examined between 1997 and 2001. The T. gondii seroprevalence was 42% (49/116) for live otters, and 62% (66/107) for dead otters. Demographic and environmental data were examined for associations with T. gondii seropositivity, with the ultimate goal of identifying spatial clusters and demographic and environmental risk factors for T. gondii infection. Spatial analysis revealed clusters of T. gondii-seropositive sea otters at two locations along the coast, and one site with lower than expected T. gondii seroprevalence. Risk factors that were positively associated with T. gondii seropositivity in logistic regression analysis included male gender, older age and otters sampled from the Morro Bay region of California. Most importantly, otters sampled near areas of maximal freshwater runoff were approximately three times more likely to be seropositive to T. gondii than otters sampled in areas of low flow. No association was found between seropositivity to T. gondii and human population density or exposure to sewage. This study provides evidence implicating land-based surface runoff as a source of T. gondii infection for marine mammals, specifically sea otters, and provides a convincing illustration of pathogen pollution in the marine ecosystem.

Audit of necropsies in a British district general hospital.

A comprehensive study was made of the value of necropsies carried out over a six month period in Peterborough Health Authority, using a modification of the format proposed by Schned et al in Vermont, United States of America. Cause of death, clinical correlation, clinical factors contributing to death and clinical evaluation of the necropsy were recorded. The principal diseases were cardiac (33%), and neoplastic (29%). The pathologist disagreed with the clinical cause of death in 13% of cases and major unsuspected diagnoses were found in 30%. Seventy nine per cent of necropsies provided additional information, including feedback on clinical investigations. Clinicians' questions were answered fully in 87%. Necropsies were rated as "very valuable" in 44% of cases, "valuable" in 54%, and "of no value" in only 2%. In 14% of cases the clinical consultant stated that the results of the necropsy would affect future clinical practice. These findings underline the essential place of necropsies in both audit and postgraduate education. The format described could conveniently be used by other pathology departments as part of an audit program.

Waterhouse-Friderichsen syndrome as a result of non-meningococcal infection.

Waterhouse-Friderichsen syndrome--massive adrenal haemorrhage in the setting of overwhelming clinical sepsis--is usually taken at necropsy to indicate meningococcal infection, and may be the only evidence of this pathogen. This report describes three fatal cases of the syndrome in which the causative organism proved to be a streptococcus. The organisms were detected during routine coroners' autopsies with histology and microbiological investigations. In two cases, the syndrome followed Streptococcus pneumoniae infection and in a third beta haemolytic streptococcus group A. Thus, adrenal haemorrhage alone cannot be taken to indicate meningococcal disease and other pathogens, particularly streptococcus, must be considered.

Inverse relationship of metabolic clearance rate of insulin to body mass index.

Twenty-five human subjects, whose body mass indices (BMI) ranged from 18.0 to 34.1 kg/m2, underwent euglycemic clamps at both low (1.5 mU/kg/min) and high (10 mU/kg/min) insulin infusion rates. Mean C-peptide concentrations were less than or equal to 0.5 ng/mL at the end of each two-hour period. The metabolic clearance rates (MCR) of insulin (mL/kg/min) were significantly (P less than .001) inversely correlated with BMI at both the low (r = -.65) and high (r = -.71) insulin infusion rates. The negative inverse correlations with BMI remained significant at both the low (r = -.42, P less than .05) and high (r = -.61, P less than .005) insulin infusion rates if the MCR were expressed as mL/m2/min. There were no significantly correlations (r less than .21) between the MCR at either rates of insulin infusion and age or tracer insulin binding to monocytes. Decreased MCR of insulin may contribute to the hyperinsulinemia seen in obese subjects.

Artificial insemination outcomes in beef females using bovine sperm with a detectable fertility-associated antigen.

In this study, semen samples from 25 bulls that had passed a breeding soundness evaluation were analyzed for the presence or absence of a 31-kDa protein, known as fertility-associated antigen (FAA), on spermatozoal membranes. Eighteen bulls had FAA on sperm (FAA-positive) and seven were devoid of FAA on sperm (FAA-negative). A single ejaculate from each bull was extended and frozen with 25 to 30 x 10(6) sperm in .5-mL straws. Crossbred replacement heifers (n = 865) were estrus-synchronized and artificially inseminated either at timed AI or 12 h after they were detected in estrus. Mature cows (n = 285) were inseminated 12 h after they were detected in estrus during a 45-d AI period. Pregnancy rates (pooled) to first AI service for females (n = 764) inseminated with FAA-positive sperm were 65.6% and were 49.7% for females (n = 386) inseminated with FAA-negative sperm (P < .005). Among the estrus-synchronized replacement heifers, pregnancy rates to synchronized AI service for heifers (n = 550) inseminated with FAA-positive sperm were 62% and were 45.7% for heifers (n = 315) inseminated with FAA-negative sperm (P < .005). These data indicate that pregnancy rates to first AI service at spontaneous and synchronized estrus are higher when using semen from bulls with detectable FAA on spermatozoal membranes compared to semen from bulls devoid of FAA on membranes. Fertility-associated antigen is an important determinant for fertility potential of sperm from bulls to be used in AI breeding programs.

Patterns of mortality in southern sea otters (Enhydra lutris nereis) from 1998-2001.

Detailed postmortem examination of southern sea otters (Enhydra lutris nereis) found along the California (USA) coast has provided an exceptional opportunity to understand factors influencing survival in this threatened marine mammal species. In order to evaluate recent trends in causes of mortality, the demographic and geographic distribution of causes of death in freshly deceased beachcast sea otters necropsied from 1998-2001 were evaluated. Protozoal encephalitis, acanthocephalan-related disease, shark attack, and cardiac disease were identified as common causes of death in sea otters examined. While infection with acanthocephalan parasites was more likely to cause death in juvenile otters, Toxoplasma gondii encephalitis, shark attack, and cardiac disease were more common in prime-aged adult otters. Cardiac disease is a newly recognized cause of mortality in sea otters and T. gondii encephalitis was significantly associated with this condition. Otters with fatal shark bites were over three times more likely to have pre-existing T. gondii encephalitis suggesting that shark attack, which is a long-recognized source of mortality in otters, may be coupled with a recently recognized disease in otters. Spatial clusters of cause-specific mortality were detected for T. gondii encephalitis (in Estero Bay), acanthocephalan peritonitis (in southern Monterey Bay), and shark attack (from Santa Cruz to Point Año Nuevo). Diseases caused by parasites, bacteria, or fungi and diseases without a specified etiology were the primary cause of death in 63.8% of otters examined. Parasitic disease alone caused death in 38.1% of otters examined. This pattern of mortality, observed predominantly in juvenile and prime-aged adult southern sea otters, has negative implications for the overall health and recovery of this population.

'Proximal-type' epithelioid sarcoma: is Agent Orange still at large?

BACKGROUND AND AIMS: Proximal-type epithelioid sarcomas of the perineum are extremely rare. The authors provide an overview of this condition in relation to the history of exposure to Agent Orange. PATIENT AND METHODS: A 54-year-old man presented with a rapidly growing perineal subcutaneous mass that was shown to be a proximal-type epithelioid sarcoma. The case is discussed. An Internet Medline search was performed and the current literature reviewed. RESULTS: Only 4 primary perineal sarcomas have been described in the literature. Epithelioid sarcomas are uncommon, aggressive tumours with a propensity for locoregional recurrence. They are recognised by the US Veterans Affairs department as linked to exposure to Agent Orange, an organochlorine defoliant containing the contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). However, the role of Agent Orange in sarcomagenesis is still controversial. CONCLUSION: Unusual soft tissue swellings in a background of chemical exposure should be investigated thoroughly with a view to early, appropriate treatment.

Medical reference databases used by Army primary care physicians in field environments.

A cross-sectional survey of U.S. Army primary care physicians was done to answer two questions: (1) which medical reference materials are Army primary care physicians currently using when deployed to a field environment? and (2) what would they like to have for medical reference in a field environment? Of 740 surveys delivered to their intended recipients, 445 (60%) were returned. Currently, 96% of primary care physicians use books, 37% use journals, and 11% use computer software in their medical reference database. Of those now using books, 72% were satisfied with them, compared with 61% of those using journals and 45% of those using software. The most common book used was the Merck Manual. The most important characteristics desired in a field medical database were broad coverage, ease of use, and light weight. The majority of respondents believe that a good medial reference database is important but that current medical databases limit the quality of the medicine they practice in the field.

Restructuring: specifics for home health.

The current reimbursement climate, job characteristics, and health care personnel shortages challenge home health nurses in providing quality patient care. Through relatively simple restructuring efforts, home health nursing can become more satisfying and productive.

The changing scene in community health nursing.

The DRGs and their aftermath have had an effect on all who are involved with home health care services, including the patient and provider. The staff of home health agencies must be competent, caring professionals who must also be able to cope with the regulatory issues that affect patient care. The effects on patients and families have also increased. Today's health care environment is requiring that they be responsible for self-care programs for many hi-tech procedures as well as care for those who are terminally ill. They are discovering that reimbursement is not available for the many services that they consider necessary, but that third-party payers consider these services to be of a custodial nature and, therefore, nonreimbursable. The effect on physicians is an increased amount of paperwork for home care services, as a result of frequent admissions to and discharges from service and changes in the frequency of visits or treatment plans. There is also the need for the timely signing of the required forms for agencies to meet the requirements of the Medicare program. The effects on the agencies include attempting to maintain financial solvency while providing quality health care services; maintaining staff morale and productivity; making hi-tech services available at an increased cost on a 24-hour basis by qualified staff to remain competitive; and guaranteeing safe, sound policies and procedures for patients and staff. Certainly the advent of DRGs has also had an impact on the nursing profession as it relates to home health care. The benefits of community health nursing identified in the past are no longer applicable in 1988. The job characteristics have changed and are no longer as attractive as they once were to nurses. In a recent publication I said there are times when I feel that I know what a swimmer experiences when being pounded by unrelenting waves in a rough surf. There is hardly time to catch your breath before the next wave hits. The DRG aftermath is just one of these waves. In spite of these never-ending waves, and the multiple internal and external changes, administrators must manage in an effective and efficient manner. We can survive the present turmoil and help to shape the future of the home care industry. Peter Drucker suggests in Managing in Turbulent Times that one should feed the opportunities and starve the problems. The challenge is to view our never-ending waves as opportunities that can take us to new heights in 1988.

The revised survey process.

The implementation of the requirements of OBRA 87 has resulted in many changes for HHAs and home healthcare nurses. These include the patient bill of rights, training and competency evaluation of home healthcare aides, and the revised certification/recertification process. It is important that sound structural and process criteria be in place in an HHA. These will provide the foundation for successful site visits during which patient-focused outcomes can be identified. Increased knowledge should also decrease the nurses' apprehension about the revised process.

Structure and process criteria assist with goal attainment.

The GQSs can be considered both structural and process criteria. These screens provide the framework and activities that help to identify patient outcomes. When both components are in place, the agency will be in a position to utilize multiple methods to identify and measure patient outcomes. Home health agency administrators, supervisors, and staff must strive for excellence in all aspects of home healthcare. A commitment to quality from the standpoint of structure, process, and outcome criteria by all members of the home care team will enable the staff and agency to meet all of the standards and regulations imposed by the Medicare Conditions of Participation, accrediting and licensing agencies, PROs, professional, agency, and individual standards.