Fixed implant rehabilitation of the edentulous maxilla: clinical guidelines and case reports. Part I

Fixed implant reconstruction is one of the most challenging prosthetic treatment alternatives for the edentulous maxilla. Accurate diagnosis and treatment planning are essential to successful, predictable clinical results. Decisions concerning the placement of implants may have a lasting impact on the quality and prognosis of the final restoration. A series of clinical guidelines and considerations is presented with illustrative clinical treatment protocols of edentulous maxillae that vary in degrees of anatomical and prosthetic difficulty. This article addresses the fixed implant rehabilitation of edentulous maxillas with favorable anatomy and favorable arch position, favorable anatomy, and unfavorable arch position, and unfavorable anatomy and favorable arch position.

Detecting film-screen artifacts in mammography using a model-based approach

Microcalcifications can be one of the earliest signs of breast cancer. Unfortunately, their appearance in mammograms can be mimicked by dust and dirt entering the imaging process and this has been shown previously to lead to false positives. We use a model of the imaging process and, in particular, the blurring functions inherent within it to detect the film-screen artifacts caused by dust and dirt and, thus, reduce false-positives. A crucial facet of the work is the choice of the correct image representation upon which to perform the image processing. After extensive testing, our algorithm has identified no microcalcifications as being artifacts and has an artifact detection rate of approaching 96%.

Taking on the student role: how can we improve the experience of registered nurses returning to study?

Regardless of the number of nurses who undertake graduate certificate courses in critical care nursing in Victoria, Australia, there is still a shortage of skilled nurses in the critical care areas. Preparation for practice in this specialist field has moved from hospital-based programs to tertiary-based courses during the past decade. As a consequence, there has been scrutiny of the clinical ability of graduates to perform the role function. Although this is understandable, anecdotal evidence to date indicates that students in these courses experience many difficulties, yet very little is written about the stressors they encounter. As the future of the critical care work force depends on a constant supply of students undertaking courses, it is essential to gain insight into the student experience, with a view to optimising it for future students and perhaps preventing attrition from courses. This paper describes a qualitative research study involving 14 students undertaking a graduate certificate course in critical care nursing. The aim of the study was to document the students' experience in relation to factors they identified as helping or hindering their progress on the course. Data were obtained at three points during the academic component of the course: on entry, at the end of semester 1 and at the end of semester 2. Interviews and questionnaires were used as the data collection methods. Results indicate that for this group of students, the experience of undertaking the course was adversely affected by stress related to three factors: change of role from clinician back to student; unmet expectations, and exhaustion. Recommendations related to preparation for study, curriculum timelines and peer support are included in this paper.

Horizontal transmission of feline immunodeficiency virus with semen from seropositive cats

The AIDS virus of cat species, feline immunodeficiency virus (FIV), has been used extensively as an animal model of HIV-1 infection. This felid lentivirus shares many molecular and biochemical traits with HIV-1 and causes similar immunologic and clinical perturbations, most notably CD4+ cell loss, impaired cell-mediated immunity and increased susceptibility to opportunistic pathogens. Previous reports have shown that FIV is transmitted horizontally by biting and vertically in utero and through nursing. Our objective was to determine whether FIV could be venereally transmitted in domestic cats. In the first experiment, susceptibility of the female reproductive tract to mucosal transmission of the FIV isolate, NCSU1, was demonstrated via intravaginal inoculation with infected cultured cells. We next identified virus in electroejaculates from asymptomatic, chronically FIV-NCSU1-infected, adult males. A fragment of FIV gag provirus DNA was detected by nested polymerase chain reaction (PCR) in nonfractionated seminal cells and in swim-up sperm preparations. Additionally, replication-competent virus was isolated from cell-free seminal plasma and seminal cells by co-cultivation with a feline CD4+ T-cell line. In the third study, queens were artificially inseminated via an intrauterine laparoscopic technique with electroejaculates from FIV-NCSU1-infected males. Of six inseminations carried out with fresh semen, three resulted in infection of queens. Lastly, immunohistochemical studies identified potential virus target cell populations in normal female reproductive tissues. In conclusion, these experiments indicate that FIV infection in domestic cats may provide a unique small animal model of sexual transmission of HIV-1.

Responses to time-varying stimuli in rat auditory cortex

Responses to frequency modulated (FM) sweeps were recorded in rat primary auditory cortex. Forty-four percent of the cells were direction-selective. For speed selectivity, the majority of the cells preferred faster sweeps. The results suggest that rat auditory cortex may be used for processing communication signals of their predators or for detecting spectral changes in acoustic signals.

Effect on attendance at breast cancer screening of adding a self administered questionnaire to the usual invitation to breast screening in southern England

STUDY OBJECTIVE

The primary aim of the research described in this paper was to ascertain whether inclusion of a self administered questionnaire with the usual invitation to routine breast screening affected screening uptake. Secondary aims included establishing appropriate questionnaire distribution and collection methods within the framework of the National Health Service Breast Screening Programme and optimisation of questionnaire design.

DESIGN

Randomised study.

SETTING

Oxfordshire and West of London Breast Screening Units.

PARTICIPANTS/METHODS

6400 women invited for routine screening mammography were individually randomised to receive either the usual breast screening invitation alone, or to receive the usual invitation accompanied by a self administered questionnaire, to be returned at the time of screening. Participants were then followed up and attendance rates at screening were compared between groups.

MAIN RESULTS

Screening attendance rates were similar in women who did and did not receive a questionnaire (71% in each group). Of those who were sent a questionnaire and attended for screening, 77% returned a completed questionnaire. Screening uptake was not affected by the way in which the questionnaire was returned or by whether or not personal details and signed permission for follow up were requested.

CONCLUSIONS

The inclusion of a self administered questionnaire accompanying the invitation to breast screening did not adversely affect screening uptake. A high proportion of women completed the questionnaire.

Cortical cell loss in asymptomatic cats experimentally infected with feline immunodeficiency virus

Specific pathogen-free cats experimentally infected with feline immunodeficiency virus (FIV) were used to evaluate the development of central nervous system changes during the asymptomatic stages of viral infection. The brains of asyptomatic cats were examined at postinoculation times ranging from 8 weeks to 3 years for changes in neuron density, glutamate receptor density, and synaptophysin immunoreactivity. At 2-3 years postinoculation a small decrease in neuronal density was found in layers 2-3 and layer 5 of the frontal cortex (-14.4%), parietal cortex (-18.1%), and striatum (-29.5%). The only other indications of pathology within these regions were a mild diffuse astrogliosis, occasional microglial nodules, and the accumulation of satellite cells around selected neurons. An average loss of large neurons of 56-68% was seen in the cortex of four random source cats euthanized with AIDS. These values contrasted with the absence of any significant cell loss in FIV-infected cats 18 weeks after inoculation or FIV-negative controls. The loss of neurons in the asymptomatic cats showed a significant positive correlation with a decrease in the blood CD4:CD8 ratios. Morphometric evaluation of synaptic terminal densities immunocytochemically stained with synaptophysin revealed a significant increase in the asymptomatic cats at 2-3 years postinoculation that correlated negatively with the CD4:CD8 ratios. Random source AIDS cats showed a 34% decrease in synaptophysin-immunoreactive profiles. Glutamate binding in the cortex did not change significantly in the asymptomatic cats (4-7% decline). Thus, experimentally infected specific pathogen-free cats show a loss of cortical neurons similar to what has been observed in postmortem studies of humans infected with HIV. The detection of neuronal loss during the asymptomatic stage of disease and the correlation with the peripheral CD4:CD8 cell ratios indicate that neurodegeneration may progress in parallel with peripheral disease.

Women doctors' use of hormone replacement therapy. High prevalence of use is not confined to doctors

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Enhanced expression of novel CD57+CD8+ LAK cells from cats infected with feline immunodeficiency virus

As a model for lymphokine-activated killer (LAK) function in HIV infection, we studied LAK cells in cats infected with feline immunodeficiency virus (FIV), which causes an acquired immunodeficiency syndrome. Peripheral blood mononuclear cells cultured in concanavalin A and interleukin-2 developed LAK cytotoxicity against chronically FIV-infected CrFK cells and acutely infected CD4+ lymphocytes but not uninfected cells. LAK cells from FIV+ cats were more cytotoxic than LAK cells from uninfected cats. Enhanced FIV+ LAK cytotoxicity against feline leukemia virus-infected cells (FL74) suggested that the cytotoxicity was not antigen specific. Two-color fluorescence-activated cell sorter analysis and antibody depletion studies demonstrated that the majority of LAK cells and their progenitors were positive for both CD8 and CD57. The in vitro induction of dual positive CD8+CD57+ LAK cells was enhanced in FIV+ cats, as reported for HIV+ patients. These CD8+CD57+ LAK cells may play a role in maintaining the long asymptomatic stage of infection in FIV+ cats.

Therapeutic effects of diethylcarbamazine and 3'-azido-3'-deoxythymidine on feline leukemia virus lymphoma formation

Twenty-four specific pathogen-free kittens were infected with the Rickard strain of feline leukemia virus (FeLVR). The kittens were divided into four equal groups and were orally administered either a high dose of diethylcarbamazine (DECH, 12 mg kg-1), a low dose of diethylcarbamazine (DECL, 3 mg kg-1), 3'-azido-3'-deoxythymidine (AZT, 15 mg kg-1, b.i.d.), or a placebo (250 mg granular dextrose) daily for 10 weeks. Blood was collected at 2-week intervals for complete blood counts (CBC) and flow cytometric analysis (FACS) of peripheral blood lymphocytes (PBL). Plasma was assayed for antibodies to FeLV gp70 and for FeLV p27 antigen using ELISA assays. For FACS analysis, lymphocytes were incubated with monoclonal antibodies to feline Pan T, CD8+, CD4+, and B cell (Anti-Ig) antigens. In the placebo treated cats, FeLVR infection caused an early (2 weeks p.i.) and persistent decrease in leukocyte numbers attributable primarily to a decrease in neutrophil numbers and a secondary lesser decrease in B and CD4+ lymphocyte numbers. The DEC-treated groups showed a delayed but similar leukopenia by 4 weeks p.i. The lymphopenia in the DEC groups (primarily B cells and CD4+ cells) was reversed by 10 weeks p.i., but the neutropenia persisted. AZT treatment inhibited FeLVR-induced lymphopenia but did not prevent a reduction in neutrophil numbers. A marked p27 antigenemia that peaked at 4 weeks p.i. was noted in the placebo treated cats and in most cats (11/12) treated with either dose of DEC. However, AZT significantly inhibited the p27 antigenemia and all cats were negative for p27 antigen between 6 and 10 weeks of treatment. In general, placebo treated cats as well as DECH and DECL cats had low levels of antibody to gp70 throughout the study, suggesting FeLVR-induced immunosuppression. In contrast, significantly higher titers of anti-gp70 antibodies were seen in AZT-treated cats at 6 weeks p.i., and were maintained throughout treatment. Eighteen month survival rates provide efficacy data for AZT as well as both DEC treatment groups. While all placebo treated cats were euthanized by 52 weeks p.i. due to FeLV associated lymphomas with a mean survival time of 35.5 weeks p.i., median survival time of the AZT treated group was > or = 102 weeks p.i., while that of the DECH and DECL groups was 69.7 and 72 weeks p.i., respectively. Thus, DEC as well as AZT therapy delays the development of lymphomas associated with FeLV infection and significantly improves survival.

Chin bone harvesting for autogenous grafting in the maxillary sinus: a clinical report

The sinus lift has become a common dental procedure when insufficient bone exists to support endosseous dental implants. The goal of the procedure is to augment existing bone in the posterior maxilla. Various resorbable and nonresorbable allograft, xenograft, and synthetic materials and mixtures, with and without autogenous bone, have been used for sinus augmentation. The authors prefer a mixture of autogenous bone with resorbable bovine xenograft, utilizing as much autogenous bone as possible. The chin offers an ideal site for bone harvesting because of its advantages over other potential sites, such as iliac crest, rib, and calvarium. These advantages include ease of accessibility, relatively simple office-based surgery, minimal morbidity, and the benefits of utilizing intramembranous versus endochondral bone. This article describes the harvesting and the sinus lift procedures. The learning objective of this article is to present this particular procedure using a clinical report to illustrate.

Achieving implant reconstruction through bilateral mandibular nerve repositioning

Grafting is one treatment option for patients who have insufficient bone for implant placement. However, repositioning the neurovascular bundle also can allow for placement of endosseous implants. This case illustrates bilateral repositioning of the mandibular nerves and subsequent implant placement.

Herpes simplex hepatitis in a patient with psoriatic arthritis taking prednisone and methotrexate. Report and review of the literature

Herpes simplex hepatitis is a rare disease in adults and with high mortality (81%). Most cases are seen in immunocompromised hosts or in the third trimester of pregnancy. A 43-year-old woman with psoriatic arthritis, treated with prednisone and methotrexate (MTX), presented with an acute abdomen and elevated liver enzymes. The diagnosis was made by liver biopsy. MTX was stopped and acyclovir was started. The patient survived. The diagnosis of Herpes simplex should be suspected in immunocompromised hosts and established by liver biopsy and viral cultures. Treatment includes parenteral acyclovir and discontinuation or reduction of immunosuppressive therapy.

Detection of periodontal disease activity with a scintillation camera

The goal of this study was to assess the ability of a scintillation camera method to detect areas of active bone loss due to periodontitis. Technetium 99m methylene diphosphonate was used as the bone-seeking radiopharmaceutical. Bone-seeking radiopharmaceutical uptake (BSRU) was imaged and quantified in alveolar bone regions of interest with a scintillation camera and a computer. Analysis of the sequential radiographs over six months constituted the basis for determination of sites of active disease. The study was composed of two parts. First, 18 subjects, nine with adult periodontitis and nine controls, were enrolled in a cross-sectional study to determine whether the quantitative scintillation amera methodology detected differences in BSRU in periodontitis vs. periodontally healthy patients. Second, the nine patients with periodontitis were studied longitudinally in order to determine whether the BSRU examination was indicative of bone loss subsequently measured radiographically. In the cross-sectional study, the mean uptake ratio for the periodontitis group was significantly higher than that for the control group (1.63 +/- 0.06 and 1.42 +/- 0.04, respectively, p less than 0.01, t test). From the longitudinal study, the mean patient scintillation image uptake ratios were highly correlated with the mean bone loss determined from serial radiographs (p less than 0.01). The accuracy, sensitivity, and specificity of the quantitative gamma camera method for detecting site(s) of active bone loss within the region of interest were assessed relative to the longitudinal radiographic data. The accuracy, sensitivity, and specificity were 85%, 90%, and 79%, respectively. Alveolar bone scintigraphy with a gamma camera and computer may provide a simple and valid technique for the immediate indication of areas of periodontal disease activity.

Human recombinant interleukin-2 induces maturation and activation signals for feline eosinophils in vivo

Immunotherapy, with interleukin-2 (IL-2) or IL-2 plus lymphokine-activated killer (LAK) cells, has been used to treat cancer and acquired immunodeficiency syndrome (AIDS) in man. Similarities between feline leukemia virus (FeLV) infection in the cat and human immunodeficiency virus (HIV) infection in man have prompted immunotherapeutic studies in the cat. To develop baseline data on hematological responses to infused IL-2, cats were given daily (1-14 days) i.v. injections of 5 x 10(4) U/kg of recombinant human IL-2 (rHulL-2). Complete blood cell (CBC) counts were done weekly. Red blood cell (RBC), neutrophil, and lymphocyte numbers did not change appreciably over the course of the study. In contrast, rHulL-2 caused an eosinophilia in all but the 1 day treatment group. Treatment for 3 days generated a transient eosinophilia on day 7 that returned to baseline by 3 weeks. Five day and 7 day treatments generated an eosinophilia by day 7 that peaked on day 14 and returned to normal values by day 28. Treatment of cats for 14 days did not increase the magnitude or duration of the eosinophilia beyond the 5 or 7 day treatments. Bone marrow (BM) biopsies from rHulL-2-treated cats revealed a marked selective hyperplasia of eosinophil precursors. In the 5 day treatment group, all maturation stages of eosinophils were elevated by week 1 of treatment. By week 2, the early stages had returned to normal, whereas the late stage cells remained elevated, suggesting an ordered maturation response. Numbers of all eosinophil precursors approximated pretreatment numbers by weeks 3-4. Thus the BM hyperplasia preceded the blood eosinophilia by 1 week, suggesting that an enhanced maturation response of BM eosinophil precursors is a major contributor to the rHulL-2-induced blood eosinophilia. In addition to a maturation signal, rHulL-2 induces a potent activation signal for eosinophils as measured by a decrease in density and an increase in longevity in culture. The significance of the activated eosinophil in the therapeutic or toxicologic response to rHulL-2 infusion is discussed.

Osteosarcoma--presumed lymph node metastases in two cases

Two patients with osteosarcoma of a lower limb and presumed lymph node metastases are described. The metastases presented in both children as palpable masses, one in the inguinal region and the other in the pelvis. One was visible on plain radiography; both were demonstrated on computed tomography and bone scintigraphy. The inguinal mass was present at the first examination and was resected with the primary lesion. The pelvic mass presented 12 months after amputation and was unresectable; its subsequent rapid growth was demonstrated by computed tomography. In one patient the osteosarcoma was of the osteoblastic type.

Five patients with Rasmussen's syndrome investigated by single-photon-emission computed tomography

Five patients with Rasmussen's syndrome (sometimes known as smouldering encephalitis), are presented. This rare form of childhood epilepsy is characterized by intractable partial seizures with progressive neurological and mental impairment. Diagnostic brain biopsy shows the histological changes of active encephalitis, consistent with a viral infection. Although the raised cerebrospinal fluid (CSF) complement and interferon levels seen in some patients support this hypothesis, no infective agent has yet been isolated. All five patients were investigated by transmission computed tomography (CT) of the head, electroencephalography (EEG) and cerebral single-photon-emission computed tomography (SPECT) using 99Tcm-hexamethylpropylenamine oxime (HMPAO) and in addition 123I-amphetamine (IMP) in Patient 1. 99Tcm-HMPAO is now regarded as reflecting cerebral perfusion, whereas the uptake of 123I-amphetamine is more dependent on cell function. In all patients SPECT imaging demonstrated an area of hypoperfusion/hypometabolism which corresponded to the anatomical localization of the epiletogenic foci found by clinical assessment, EEG and CT. In all cases the SPECT study also demonstrated a more extensive area of abnormality than CT, and in the two patients who had sequential studies, alteration in the size of the defect was found which correlated with the patients' changing clinical condition. SPECT imaging in Rasmussen's syndrome may facilitate anatomical localization of the area of pathology, and may demonstrate a changing pattern in cerebral hypoperfusion/hypometabolism. It could also serve as a guide to accurate brain biopsy.

Viral encephalitis: imaging with SPECT

SPECT brain imaging performed in two patients with presumed herpes encephalitis demonstrated greater sensitivity and more precise localization than either planar brain imaging or CT scanning.

Single photon emission computed tomography in Alzheimer's disease. Abnormal iofetamine I 123 uptake reflects dementia severity

To determine whether abnormalities in regional cerebral functional activity estimated by iofetamine hydrochloride I 123 and single photon emission computed tomography can be detected in mild or moderate as well as severe cases of Alzheimer's disease (AD), we performed iofetamine I 123-single photon emission computed tomography in 37 patients with probable AD (nine patients with mild, 18 patients with moderate, and ten patients with severe dementia) and nine age-matched control subjects. Iofetamine I 123 uptake was measured in right and left frontal, temporal, parietal, and occipital cortices. Mean (right and left) iofetamine I 123 activity was lowest in the parietal region of patients with AD and was significantly reduced in the other three regions compared with control subjects. Only in the parietal region was lower relative iofetamine I 123 activity associated with an impaired level of patient function and with cognitive deficit.

Metacarpophalangeal arthropathy associated with manual labor (Missouri metacarpal syndrome). Clinical radiographic, and pathologic characteristics of an unusual degeneration process

We describe 7 manual laborers with painful, palpably enlarged metacarpophalangeal joints. Characteristic radiographic changes were joint space loss, prominent osteophytes, and cystic metacarpal heads most prominent in the second and third metacarpophalangeal joints. In 3 of 4 patients, joint biopsy specimens showed subsynovial fibrosis and villous hyperplasia. All 7 patients had similar backgrounds of heavy work demanding sustained gripping motions of both hands, for periods that exceeded 30 years. We designated their condition metacarpophalangeal arthropathy associated with manual labor.