Resident training and managed care: what's really going on?
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Academic Medical Centers↗
Biomedical subjects
C Howard
Publications and source records attributed to C Howard.
In vivo experimental analysis of silicone implants used with titanium grommets.
This study evaluated the titanium grommets recommended to reduce breakage by protecting hinge implants from bone edges. Silastic HP-100 (Dow Corning Wright, Arlington, TN) flexible finger implants (size 5) were used to replace one knee of 10 rabbits, and implants plus titanium grommets were used in another 10. X-ray films were taken monthly; deaths from each group were 1 animal at 2 and 4 months, 2 animals at 6, and 3 each at 12 and 16 months. X-ray films revealed that 4 of 10 implants from each group had fractured. Silicone fractures occurred identically at the proximal stem-hinge junction in both groups, destruction was always most pronounced at the dorsal surface of the proximal stems. The time from surgery to x-ray film evidence of implant fracture without grommets was an average of 9 months and with grommets 13 months. Although grommets delayed x-ray film evidence of fracture onset, after 14 months all implants in both groups of animals fractured. These findings do not support the hypothesis that grommets prevent silicone hinge implant wear or fracture in this experimental model.
Animals↗
In vivo experimental analysis of silicone implants on bone and soft tissue.
We report experimentally produced silicone microparticles (synovitis) in 47 white rabbits and discuss the implications for clinical practice. Silastic HP100 (Dow Corning Wright, Arlington, TN) finger hinges (size 5) were inserted in 20 rabbit's knees. The upper tibia was replaced with Swanson design great toe implants in another 15 rabbits; articular cartilage was removed and endosteal drilling was performed in 6 animals as a "sham" arthroplasty. Small silicone blocks were inserted in the proximal tibial endosteal canal of 6 others. Animals were followed by monthly x-ray films and killed at 2, 4, 6, 12, and 16 months. Implant wear, bone surfaces, and soft tissue were examined under the operating microscope and by light microscopy; implant surfaces were examined with scanning electron microscopy. X-ray changes included reactive endosteal bone formation around implant stems as early as 1 month postoperatively; at 2-3 months the new bone line was clearest but it became progressively homogeneous and less evident. Extensive cortical erosion around the stems was observed in one third of the animals. Neither ossification nor lysis was observed around the silicone block. Proliferative synovitis was found at post-mortem examination beginning after 4 months; femoral condylar erosions were observed in most animals after 12 months. Wherever there was bone destruction, silicone particles were confirmed by x-ray spectrography.
Animals↗
Effect of level of lung injury on HR, MAP and SaO2 changes during suctioning.
25 patients with documented lung injury were suctioned using a manual resuscitation bag (MRB) and a standardised procedure. Level of lung injury was not significantly correlated with changes from baseline in heart rate (HR) oxygen saturation (SaO2) or mean arterial pressure (MAP). However, HR and MAP increased significantly returning to baseline at 5 min. Patients' SaO2 did not change significantly during the procedure or up to 15 min afterwards. No changes in cardiac rhythm were found during the event or for 15 min afterwards. Standards for hyperoxygenation and hyperinflation could not be achieved using the MRB even with a standardised procedure.
Adult↗
Delayed somatic growth and pubertal development in human immunodeficiency virus-infected hemophiliac boys: Hemophilia Growth and Development Study.
As part of the Hemophilia Growth and Development Study, we investigated the impact of human immunodeficiency virus (HIV) infection on statural growth, weight gain, and skeletal and sexual maturity in more than 300 boys with moderate to severe hemophilia, of whom 62% were infected with HIV. Age-adjusted height and weight were reduced in the HIV-infected subjects (p < 0.001). However, mean weight for height and triceps skin-fold thickness of the infected-boys closely resembled those of the uninfected group. In HIV-infected boys, height for age was positively related to the CD4+ lymphocyte count when the count was < 200 cells/mm3. Age-adjusted serum testosterone levels did not differ by HIV status, but in the infected participants the mean age-adjusted bone age was significantly reduced (p = 0.038) and the distribution of Tanner stages, adjusted for age, differed significantly (p = 0.003). The probability of advancing one or more Tanner stages in the first study year was significantly slowed in HIV-infected boys more than 14 years of age (p = 0.0003). We conclude that linear growth was significantly impaired in boys with hemophilia and HIV infection, but the wasting of malnutrition was not found. The delays in bone age and pubertal maturation strongly suggest that part of the growth failure seen in acquired immunodeficiency syndrome can be attributed to pubertal delay. We speculate that the lack of demonstrable difference in age-adjusted testosterone concentrations might reflect subtle differences in the pattern of secretion of testosterone or in the concentration of sex-hormone binding globulin.
Adolescent↗
Breakthrough infections and identification of a viral variant in Gambian children immunized with hepatitis B vaccine.
Hepatitis B (HB) breakthrough infections, identified by the presence of HB core (c) antibody, were found in 32 of 358 Gambian children vaccinated with plasma-derived HB vaccine. Over 2 years, 15 of these children lost their HBc antibodies. These children had significantly higher HB surface antibody levels before infection than those who retained HBc antibodies. One child, who responded well to the vaccine, had HB viral DNA detected in the presence of HBs antibodies. The S gene sequence of this DNA showed nucleotide changes that resulted in an amino acid substitution at residue 141 (lysine to glutamic acid) of the surface antigen. This finding suggests the child was infected with a variant virus that was not neutralized by antibodies resulting from HB vaccination.
Child↗
Seroprevalence of HIV-1 and HIV-2 infection among children diagnosed with protein-calorie malnutrition in Nigeria.
Excessive weight loss due to protein calorie malnutrition (PCM) is a significant problem in Nigerian children. This syndrome may be difficult to differentiate from the wasting disease caused by human immunodeficiency virus type 1 (HIV-1) infection. We studied 70 children admitted to the Baptist Medical Center in Ogbomosho, Nigeria in 1990 with PCM for prevalence of antibodies to HIV-1 and HIV-2. The cohort was from low-risk mothers and had a median age of 25 months (range, 4 months-9 years) with a weight deficit of at least 20% of the theoretical weight for age. Two sera were positive for anti-HIV-1 by both ELISA and Western blot (WB). A high prevalence of samples negative for HIV-1 antibody by ELISA were repeatedly reactive (11%, 8/70) or indeterminate (46%, 32/70) by WB. None of the sera was positive for antibody to HIV-2. There was no correlation of ELISA positivity or extent of WB banding with successful recovery from malnutrition. These results indicate a relatively low but significant prevalence of HIV-1 infection in Nigerian children with PCM. The high prevalence of indeterminate reactions in WB assays for HIV-1 suggests that other procedures may be necessary for confirmatory diagnosis of HIV-1 infection in this African population.
Blotting, Western↗
The effect of aprotinin on the response of the activated partial thromboplastin time (APTT) to heparin.
Aprotinin, a broad spectrum serine proteinase inhibitor, is becoming increasingly used to control bleeding during surgery. Heparinized patients treated with aprotinin for cardiac surgery have a much longer activated clotting time (ACT) than expected for the dose of heparin used and a similar effect has been observed with the activated partial thromboplastin time (APTT). Since APTT reagents vary in their sensitivity to heparin we compared the effect of aprotinin on 25 commercially available products with respect to the APTT response to heparin. Aprotinin (Bayer) was added to normal, pooled, citrated plasma at concentrations of 0, 100, 200, 300 and 400 kallikrein inhibition units (KIU)/ml and mucosal heparin was then added to give concentrations of 0, 0.25, 0.5, 0.75 and 1.0 IU/ml. Duplicate APTTs were performed on each of these 25 plasma samples according to the manufacturers' instructions. As expected, different commercial reagents exhibited different sensitivities to heparin. There was also variation in the sensitivity to aprotinin but this did not correlate with the heparin sensitivity. The prolongation of the APTT by heparin was markedly increased by aprotinin. For example, APTT ratios at 0.5 IU/ml heparin increased up to eight-fold in the presence of 'therapeutic' levels of aprotinin (200 KIU/ml) and this effect was even more pronounced at higher heparin levels. The activator used did not significantly influence the effect of aprotinin on the APTT although there was a trend for kaolin-activated reagents to be less affected by the addition of aprotinin to heparinised plasma.(ABSTRACT TRUNCATED AT 250 WORDS)
Aprotinin↗
Comparison of an EBV transformed cell line and an EBV hybridoma cell line producing the same human anti-HBs monoclonal antibody.
A stable human-mouse heterohybridoma secreting human anti-HBs monoclonal antibody in continuous culture for 12 months was generated. It grew faster than the parent EBV transformed lymphoblastoid cell line (LCL) but produced the same level of specific antibody. The LCL was positive for the Epstein-Barr Virus Nuclear Antigen (EBNA), human CD 23 and contained a diploid number of human chromosomes. The heterohybridoma was negative for EBNA, CD 23 and mouse Ly-1 mouse, despite retaining a full complement of diploid mouse chromosomes and a limited number of human chromosomes.
Animals↗
Development and characterization of human anti-HBs antibodies.
Peripheral blood mononuclear cells (PBMC) from 13 healthy hepatitis B vaccines were transformed with the Epstein-Barr virus (EBV) and lymphoblastoid cell lines (LCL) producing antibodies to hepatitis B surface antigen (anti-HBs antibodies). Seven LCL and two clones secreting human anti-HBs monoclonal antibody were generated and their antibodies purified. One clone was fused with a mouse myeloma and the antibody from a cloned anti-HBs secreting heterohybridoma purified. One of the 10 purified human anti-HBs antibodies was characterized as IgG4, the remainder were IgG1. The antibodies had either kappa or lambda light chains. Five of the antibodies which were conjugated to horseradish peroxidase recognised the "a" group determinants.
Antibody Specificity↗
Brucellosis induced avascular necrosis of the femoral head in a 7 year old child.
The case is reported of a 7 year old Bedouin girl who presented with a three week history of fever and limp. Initial tests for rheumatoid factor, antinuclear antibodies, and brucella were negative. Two weeks after admission Brucella melitensis was cultured from bone marrow and synovial fluid samples. The patient improved after treatment with doxycillin and streptomycin, but radiographs of the right hip showed avascular necrosis of the right femoral head. A mild limp and limitation of motion in the right hip persisted 18 months after admission.
Brucella↗
The Oxford club-foot programme.
We treated 63 club feet in 44 patients by a defined programme of strapping from birth followed by one of two operations performed at six weeks, either a simple calcaneal tendon lengthening or a subtalar realignment, and reviewed them prospectively. The decision as to which operation to perform was taken at four weeks after radiographic measurement of the talocalcaneal angle. All but eight patients (ten feet) were followed for a mean of 8.7 years. The overall results after calcaneal tendon lengthening were satisfactory. The re-operation rate after subtalar realignment was high (39%) due to over or undercorrection of the deformity.
Child↗
A fully automated enzyme immunoassay for the measurement of cortisol in biological fluids.
This paper describes a fully automated assay on the Serono SR1 for the measurement of cortisol in serum, heparinised plasma and urine. The assay incorporates a specific polyclonal antibody to cortisol and cortisol conjugated to alkaline phosphatase as a label. Following immunoincubation, bound and free labelled cortisol are separated by magnetic sedimentation of the antibody complex. Phenolphthalein is liberated by the enzymatic hydrolysis of the substrate (phenolphthalein monophosphate) and the absorbance generated is measured as the assay end-point. All processing steps are performed by the SR1. The assay has good analytical performance with respect to precision (within and between run CVs less than 10 and 11.5% respectively), detection limit (less than 5 nmol/l) and recovery of added cortisol (100 +/- 10%). The assay agrees well with cortisol concentrations determined by ID-MS and by established immunoassays (r > 0.96). Reference ranges of normal urine samples (pretreated by solvent extraction) are in good agreement with accepted values. The study demonstrates that the SR1 Cortisol assay on the SR1 analyzer is suitable for the routine determination of cortisol in serum, heparinised plasma and urine samples.
Adult↗
Case report: mixed-field agglutination in a patient with a weak D antigen presenting as a possible fetal-maternal hemorrhage.
A gravida 1, para O, 17-year-old black female was found on prenatal testing to be group O, Du+, the latter test showing many unagglutinated cells. Because of the mixed-field appearance, the patient was thought initially to have bad a fetal-maternal hemorrhage. Additional red cell typings were performed, but no other apparent mixed-field reactions were observed. The Kleihauer- Betke test and hemoglobin electrophoresis indicated that the mixed-field agglutination was not due to a fetal-maternal hemorrhage. Thus, the finding of a mixed-field D typing could he explained best by a weak D antigen.
Journal Article↗
HIV-infected dental staff.
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Cross Infection↗
The relative effectiveness of symbols and words to convey photocopier functions.
Two experiments have been conducted to examine preference patterns of inexperienced users for symbols intended to communicate photocopier functions and the relative effectiveness with which keywords, subject-generated symbols and industry symbols are matched to verbal descriptions of various photocopier operations. First, inexperienced photocopier users were asked to draw a set of symbols that they believed best represented 16 designated copier functions, and subsequently a second set of subjects compared these generated symbols with those currently used by the photocopier industry, and gave their preference. Inexperienced users generally preferred the subject-generated symbols, except for those involving the fairly complex 'sidedness' functions. Secondly, inexperienced users were asked to match keywords, generated symbols and industry symbols to verbal descriptions of the same 16 photocopier functions. Essentially, keywords and generated symbols did not differ in matching accuracy, while both were more accurately matched than industry symbols. However, the complexity of the photocopier function to be conveyed and the familiarity of the user with a given copier operation did produce several exceptions to this overall pattern. The results suggest that careful ergonomics research can produce symbols that are at least as effective as keywords in conveying photocopier functions. The universal nature of such symbols and their possibilities for cross-cultural use are also noted.
Journal Article↗
Esotropia following radial keratotomy.
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Adult↗
Quadriparesis in the Laurence-Moon-Biedl-Bardet syndrome: case report.
A 36 year old patient known to suffer from the Laurence-Moon-Biedl-Bardet syndrome (LMBBS) developed spastic quadriparesis. The typical features of the syndrome, presented by this patient were polydactyly, obesity, hypogonadism, retinitis pigmentosa and relative mental retardation. Severe spinal cervical and lumbar canal stenosis imaged by plain X-rays and computerised tomography was found. Magnetic resonance imaging showed significant atrophy of the spinal cord, indicating that the cause of the quadriparesis was cervical myelopathy. The patient underwent laminoplasty with some improvement.
Adult↗