Validating the Subcutaneous Model of Injectable Autologous Cartilage Using a Fibrin Glue Scaffold

PURPOSE

To create and validate an injectable model for autologous in vivo cartilage engineering with ultimate clinical applicability in human subjects.

HYPOTHESIS

Cartilage can be generated subcutaneously using fibrin glue and autologous chondrocyte components.

BACKGROUND

To date, cartilage engineering studies have been limited by several factors. Immunocompromised animals and nonautologous chondrocytes have been successfully used to create cartilage, but results using identical designs failed in immunocompetent subjects. Recent studies using more biocompatible tissues and matrices have been performed with both in vitro and in vivo steps. Although successful, several problems are notable. In vitro cartilage displays a poor modulus of elasticity, even after in vivo implantation. Variable deformation and volume loss occurs when in vitro specimens are matured in vivo. These concerns limit the clinical utility of these methods. We therefore set out to create autologous cartilage using a model that was clinically feasible, easy to create, and could be performed with very low patient harvest morbidity.

MATERIALS AND METHODS

Eight New Zealand white rabbits underwent a unilateral harvest of ear cartilage. Samples were then digested using standard methods. Cell counts and survival assays were performed before implantation. One sample of fibrin glue (Tisseel) and chondrocytes was injected subcutaneously into each donor rabbit and then left in situ for 3 months. A second sample with both basic fibroblast growth factor (b-FGF) and insulin-like growth factor (IGF)-1 in the injection suspension was also assessed (for a total of 16 samples). After harvest, analysis of overall volume, histology, and chondrocyte drop out counts was performed.

RESULTS

Cartilage formation occurred in 8 of 14 (57%) specimens that were obtained at the time of sacrifice. Of note, 6 of 7 (85%) non-growth-factor containing samples yielded positive results. Comparison with the success rate using concomitant growth factors (2/7) showed a negative effect on cartilage yield (P = .015). Chondrocyte survival, based on chondrocyte dropout counts, was not effected. Angiogenesis appeared to correlate with cartilage formation in the central regions of the implant. Alcian blue demonstrated the presence of active matrix deposition, and elastin Verhoff-van Geison (EVG) stains were positive, showing an elastic cartilage phenotype. Very limited osteoid formation was seen in successful implants. Failed implants demonstrated avascular necrosis, giant cell reactions, and inflammatory infiltrates.

CONCLUSIONS

This study validates the subcutaneous site as a recipient bed for the engineering of autologous cartilage in vivo. It also represents the first subcutaneous implantation of fibrin glue and chondrocytes in an immunocompetent host as well as the first published report of elastic cartilage generation in vivo. Although the model needs to be further streamlined to increase yields and overall volume, this study clearly demonstrates the feasibility of in vivo chondrogenesis (85% success). The addition of FGF and IGF-1 at the concentrations used negatively influenced cartilage yield. However, extrapolation of these results to other combinations or concentrations can not be done, and this issue deserves further investigation.

Vitamin D receptor gene allelic variants, bone density, and bone turnover in community-dwelling men

The role of vitamin D receptor (VDR) gene polymorphisms in the determination of bone mass and bone turnover is controversial in women. The aim of the study was to determine whether VDR polymorphisms are associated with indices of bone mineral density (BMD) (by dual-energy X-ray absorptiometry and by ultrasound) and/or with bone turnover and muscle strength, factors related to both BMD and fracture risk. For this purpose, we investigated a cohort of community-dwelling men >70 years (n = 271) and a group of healthy control subjects between the ages of 20 and 50 years (n = 137). VDR TaqI, ApaI, and FokI genotypes were determined using enzymatic restriction digestion of polymerase chain reaction (PCR) fragments. In the elderly group, the lowest BMD value at the femoral neck and at the calcaneus was observed in subjects with the "At-At" haplotype genotype, with differences between extreme haplotype groups ("At-At" vs. noncarriers of the "At" allele) ranging from 5.8% to 34.3% (p < or = 0.05). Moreover, at the different subregions of the distal forearm and the tibia, the lowest BMD estimates were consistently associated in both elderly and younger men with the "At" haplotype allele, although this did not approach statistical significance. Elderly subjects with the "At-At" genotype had a significantly higher serum osteocalcin level. BMD was not significantly related to the FokI VDR polymorphism at any of the assessed skeletal sites, nor were any of the biochemical markers associated with the FokI VDR genotype. There were no differences between genotype groups for any of the indices of muscle strength. The present study indicates that the VDR genotype is associated with BMD in healthy community-dwelling elderly men and tends to be associated with biochemical markers, particularly of bone formation, in elderly men.

Is Chlamydia pneumoniae found in spinal fluid samples from multiple sclerosis patients? Conflicting results

Cerebrospinal fluid samples from controls and patients with multiple sclerosis (MS) were split and sent to laboratories with different experiences for the detection of Chlamydia pneumoniae by polymerase chain reaction. Vanderbilt investigators identified C. pneumoniae in the majority of patients with MS and uncommonly in controls. Laboratories at Johns Hopkins University, University of Umeå, and the Centers for Disease Control and Prevention did not identify C. pneumoniae in any of the samples. Conflicting reports of C. pneumoniae detection in the some samples from patents with MS highlight the need to exchange detection techniques among laboratories involved in this controversy.

Positive feedback circuits and adaptive regulations in bacteria

The mechanisms by which bacteria adapt to changes in their environment involve transcriptional regulation in which a transcriptional regulator responds to signal(s) from the environment and regulates (positively or negatively) the expression of several genes or operons. Some of these regulators exert a positive feedback on their own expression. This is a necessary (although not sufficient) condition for the occurrence of multistationarity. One biological consequence of multistationarity may be epigenetic modifications, a hypothesis unusual to microbiologists, in spite of some well-known epigenetic modifications in bacteria. We propose here that the occurrence of mucoidy in the opportunistic pathogen Pseudomonas aeruginosa, which is currently attributed to mutations only, may also be an epigenetic modification. A theoretical approach using a generalised logical analysis lends credit to this hypothesis and suggests experiments to ascertain it.

Accuracy of prenatal diagnosis of congenital heart defects

OBJECTIVES

(1) To evaluate the detection and accuracy of fetal echocardiography for congenital heart defects (CHD). (2) To compare the detection and accuracy of a team of maternal fetal medicine specialists and radiologists (MFM/R) with those of perinatal cardiologists (PC).

METHODS

All fetal echocardiograms performed from 1/91 to 6/95 were reviewed retrospectively. CHD diagnoses made prenatally were compared with postnatally-confirmed diagnoses.

RESULTS

106 heat defects were correctly detected prenatally. There were 10 incorrect diagnoses, 6 false-negatives and 4 false-positives. Overall detection rate (sensitivity) was 95%, while overall accuracy was 87%. Detection rate for MFM/R and PC were 91 and 97%, respectively (p = 0.4). Accuracy was 74% for MFM/R and 92% for PC (p = 0.02).

CONCLUSIONS

CHD can be identified reliably by prenatal echocardiography. The involvement of a PC in the prenatal diagnosis of these defects may improve diagnostic accuracy.

Using computer graphics to preserve function in resection of malignant melanoma of the foot

The increasing incidence of malignant melanoma challenges physicians to find innovative ways to preserve function and appearance in affected areas that require partial resection. We carefully planned the resection of a malignant lesion between the third and fourth toes of a 77-year-old man with the aid of computer technology. The subsequent excision of the third, fourth, and fifth digits was executed such that the new metatarsal arc formed would approximate the dimensions of the optimal hyperbola, thereby minimizing gait disturbance.

The Edinburgh Mouse Atlas: using the CD

This paper provides a simple introduction to the reconstructions and data-handling tools stored on the Edinburgh Mouse Atlas CD, together with some of the ways in which the viewers and software can be used to understand mouse development and analyse data. The key aspect of the Mouse Atlas is that the underlying models are a complete representation of the histology, which has not been constrained to a particular interpretation. This means, for example, that the current anatomy domains can be further subdivided as required to any resolution up to the resolution of the models (2-7 microm). In the CD of the early embryos described here, virtually all tissues that can be usefully distinguished either by the histology or morphologically have been delineated.

Increased serum S100beta protein concentrations following severe head injury in humans: a biochemical marker of brain death?

This study investigated S100beta protein as a biochemical serum marker of brain damage in severe head injury and brain death victims. Blood samples obtained from 15 patients with severe head injury admitted to the trauma intensive care unit (ICU), five patients with a diagnosis of brain death due to hemorrhage following cerebral aneurysm rupture, and five healthy individuals were investigated. The S100beta protein serum concentrations were analyzed with a immunoradiometric assay kit. The 15 patients with severe head injury were followed up for 6 months. Outcome was considered either death or recovery with ICU discharge. S100beta concentrations were closely related to brain damage. Among the severe head injury victims, higher S100beta concentrations were detected in those patients that progressed to death. The individuals with brain death had similar mean S100beta concentrations, irrespective of its cause (either trauma or vascular rupture). S100beta protein is a promising serum outcome predictor for severe head injury victims and may contribute to the early diagnosis of brain death.

Multistationarity, the basis of cell differentiation and memory. II. Logical analysis of regulatory networks in terms of feedback circuits

Circuits and their involvement in complex dynamics are described in differential terms in Part I of this work. Here, we first explain why it may be appropriate to use a logical description, either by itself or in symbiosis with the differential description. The major problem of a logical description is to find an adequate way to involve time. The procedure we adopted differs radically from the classical one by its fully asynchronous character. In Sec. II we describe our "naive" logical approach, and use it to illustrate the major laws of circuitry (namely, the involvement of positive circuits in multistationarity and of negative circuits in periodicity) and in a biological example. Already in the naive description, the major steps of the logical description are to: (i) describe a model as a set of logical equations, (ii) derive the state table from the equations, (iii) derive the graph of the sequences of states from the state table, and (iv) determine which of the possible pathways will be actually followed in terms of time delays. In the following sections we consider multivalued variables where required, the introduction of logical parameters and of logical values ascribed to the thresholds, and the concept of characteristic state of a circuit. This generalized logical description provides an image whose qualitative fit with the differential description is quite remarkable. A major interest of the generalized logical description is that it implies a limited and often quite small number of possible combinations of values of the logical parameters. The space of the logical parameters is thus cut into a limited number of boxes, each of which is characterized by a defined qualitative behavior of the system. Our analysis tells which constraints on the logical parameters must be fulfilled in order for any circuit (or combination of circuits) to be functional. Functionality of a circuit will result in multistationarity (in the case of a positive circuit) or in a cycle (in the case of a negative circuit). The last sections deal with "more about time delays" and "reverse logic," an approach that aims to proceed rationally from facts to models. (c) 2001 American Institute of Physics.

Multistationarity, the basis of cell differentiation and memory. I. Structural conditions of multistationarity and other nontrivial behavior

A biological introduction serves to remind us that differentiation is an epigenetic process, that multistationarity can account for epigenetic differences, including those involved in cell differentiation, and that positive feedback circuits are a necessary condition for multistationarity and, by inference, for differentiation. The core of the paper is comprised of a formal description of feedback circuits and unions of disjoint circuits. We introduce the concepts of full-circuit (a circuit or union of disjoint circuits which involves all the variables of the system), and of ambiguous circuit (a circuit whose sign depends on the location in phase space). We describe the partition of phase space (a) according to the signs of the ambiguous circuits, and (b) according to the signs of the eigenvalues or their real part. We introduce a normalization of the system versus one of the circuits; in two variables, this permits an entirely general description in terms of a common diagram in the "circuit space." The paper ends with general statements concerning the requirements for multistationarity, stable periodicity, and deterministic chaos. (c) 2001 American Institute of Physics.

Atypical features prompting neuroimaging in acute optic neuropathy in adults

BACKGROUND

Acute optic neuropathy due to an intracranial lesion may masquerade as optic neuritis or nonarteritic anterior ischemic optic neuropathy (NAION). We reviewed the records of patients who presented with acute unilateral optic neuropathy that was initially diagnosed as optic neuritis or NAION but who ultimately proved to have an underlying structural lesion.

METHODS

Retrospective observational case series. We reviewed the records of patients with the initial diagnosis of optic neuritis or NAION in whom the diagnosis was changed to an intracranial etiology at four tertiary care neuro-ophthalmology centres between 1995 and 1998.

RESULTS

Eight cases were identified in which atypical features prompted further investigation, including neuroimaging, leading to the diagnosis of an intracranial etiology for the optic neuropathy. Five patients were discovered to have neoplasms (a tuberculum sellae meningioma in two cases, an optic nerve sheath meningioma in two cases and a metastatic lesion in one case), and three patients had intracranial sarcoidosis. Atypical features for optic neuritis included a progressive course, absence of pain, optic atrophy at presentation, lack of significant visual improvement and age over 40 years. For NAION, the atypical features included progressive course, optic atrophy on presentation, absence of vasculopathic risk factors and preceding transient visual loss.

INTERPRETATION

Clinicians should be aware that patients with intracranial lesions may present with acute optic neuropathy mimicking optic neuritis or NAION and that certain atypical features should warrant consideration for neuroimaging.

The significant change for the Timed 25-foot Walk in the multiple sclerosis functional composite

The Timed 25-Foot Walk is under evaluation as a clinical tool to follow patients with MS. Several approaches have been taken to define a clinically significant change in this measurement. This study was undertaken to define the range of values expected for the Timed 25-Foot Walk and to correlate prospectively the change in walk-time that occurs during an exacerbation of MS associated with subjective difficulty walking. Five results from this study are emphasized. (1) Patients who were minimally affected by MS frequently walked 25 feet between three and five seconds. (2) the walk-time variability, defined as the ratio of the longest to the shortest walk-time, minus 1, times 100%, for three consecutive trials was generally 20% or less; (3) if the two fastest walk-times obtained in three trials were compared, the walk-time variability was almost always 10% or less; (4) for clinically stable individuals, the walk-times of single trials separated by 12 months or less generally varied less than 20%; and (5) patients who complained of difficulty walking, but who did not have changes otherwise detectable by examination, generally had a prolongation of walk-time. These results suggest that an increase of more than 20% in the Timed 25-Foot Walk may indicate a significant change in gait. Multiple Sclerosis (2000) 6 286 - 290

Tay-Sachs disease and HEXA mutations among Moroccan Jews

Moroccan Jewry (N>750,000) is the only non-Ashkenazi Jewish community in which Tay-Sachs disease (TSD) is not extremely rare. Previous studies among Moroccan Jewish TSD families identified three HEXA mutations. In this study, extended to enzyme-defined and new obilgate TSD carriers, we found four additional mutations. One of them is a novel, IVS5-2(A-->G) substitution, resulting in exon skipping, and it was found only among enzyme-defined carriers. The seven HEXA identified mutations among Moroccan Jews are: deltaF(304/305), R170Q, IVS-2(A-->G), Y180X, E482K, 1278+TATC, and IVS12+1(G-->C). Their respective distribution among 51 unrelated enzyme-defined and obligate carriers is 22:19:6:1:1:1:1. The mutation(s) remain unknown in only three enzyme-defined carriers. Five of the seven Moroccan mutations, including the three most common ones, were not found among Ashkenazi Jews. Compared with the much larger and relatively homogeneous Ashkenazi population, the finding among Moroccan Jews probably reflects their much longer history.

Stimulus novelty differentially affects attentional allocation in PTSD

BACKGROUND

This study investigated attentional allocation in 39 Vietnam combat veterans, 25 with and 14 without posttraumatic stress disorder, assessing P300 amplitudes and latencies during both three-tone and novelty "oddball" tasks.

METHODS

The three-tone oddball task consisted of three stimuli: frequent tones (85%), rare target tones (7.5%), and rare distractor tones (7.5%). The novelty oddball task was identical to the three-tone task except that the rare distractor tones were replaced with nonrepeating novel sounds (7.5%).

RESULTS

Combat veterans with posttraumatic stress disorder showed significant P300 amplitude enhancements at frontal sites in response to distracting stimuli during the novelty but not during the three-tone oddball tasks. There were no amplitude differences in target tones during either task.

CONCLUSIONS

The data suggest that combat veterans with posttraumatic stress disorder demonstrate P300 responses consistent with a heightened orientation response to novel, distracting stimuli. This finding is consistent both with the clinical presentation of the disorder and with theoretical notions that individuals with posttraumatic stress disorder demonstrate information-processing biases towards vague or potentially threatening stimuli.

Fluorescein fluorescence hyperpolarization as an early kinetic measure of the apoptotic process

The ability to identify apoptotic cells within a complex population is crucial in the research and diagnosis of normal physiology and disease states. The Cellscan mark S (CS-S) cytometer was used in this study to detect intracellular fluorescence intensity and polarization (FI and FP) in several well-established models of apoptosis: Following spontaneous apoptosis, as well as glucocorticoid or anti Fas-induced apoptosis, CS-S individual cell-based analysis revealed the appearance of a cell cluster characterized by low FI and high FP. Temporal analysis of annexine V binding and FP measurements following DXM treatment showed that hyperpolarization preceded phosphatidylserine appearance on the outer plasma membrane. The early increase in FP was found to be dose dependent and inversely related to cell diameter. Cell dehydration and alteration of plasma membrane transport properties, both occurring during early stages of apoptosis, may be involved in the phenomena of intracellular fluorescein hyper-polarization in apoptosis.

Positive feedback circuits and memory

The concept of regulatory feedback circuit refers to oriented cyclic interactions between elements of a system. There are two classes of circuits, positive and negative, whose properties are in striking contrast. Positive circuits are a prerequisite for the occurrence of multiple steady states (multistationarity), and hence, they are involved in all processes showing hysteresis or memory. Endogenous or exogenous perturbations can lead the system to exhibit or to evoke one particular stable regime. The role of positive circuits in cell differentiation and in immunology is well documented. Negative circuits are involved in homeostatic regulation, with or without oscillations. The aim of this paper is to show: a) that positive circuits account for many features of memory stricto sensu (i.e., neural memory and mnesic evocation) as well as largo sensu (e.g. differentiation or immunological memory); and b) that simple combinations of positive and negative circuits provide powerful regulatory modules, which can also be associated in batteries. These entities have vast dynamical possibilities in the field of neurobiology, as well as in the fields of differentiation and immunology. Here we consider a universal minimal regulatory module, for which we suggest to adopt the term 'logical regulon', which can be considered as an atom of Jacob's integron. It comprises a positive and a negative circuit in its interaction matrix, and we recall the main results related to the simultaneous presence of these circuits. Finally, we give three applications of this type of interaction matrix. The first two deal with the coexistence of multiple stable steady states and periodicity in differentiation and in an immunological system showing hysteretic properties. The third deals with the dual problems of synchronization and desynchronization of a neural model for hippocampus memory evocation processes.

Analysis of enzyme kinetics in individual living cells utilizing fluorescence intensity and polarization measurements

BACKGROUND

The Cellscan mark-S (CS-S) scanning cytometer was used for tracing enzymatic reactions in the same individual cells under various physiological conditions over periods of minutes. On-line reagent addition and changes in the experimental conditions (buffers, ions, substrates and inhibitors) were performed.

METHODS

Kinetic events were monitored by fluorescence intensity (FI) and fluorescence polarization (FP) measurements of fluorescein diacetate (FDA) and chloromethyl fluorescein diacetate (CMFDA) intracellular hydrolysis. FP measurements have been used to assess the intracellular marker's mobility restrictions.

RESULTS

Kinetic measurement along 1000 s of FDA labeled individual Jurkat T cells, indicated variation of 65% for FI(t) and approximately 10% for FP(t). While FI increased linearly with time, FP(t) decreased nonlinearly and asymptotically, reaching a constant value. The FP(t) of CMFDA-labeled cells was different from that of FDA-labeled cells. Average cellular Km of 3.9 microM was calculated from individual cell FDA hydrolysis curves.

CONCLUSIONS

(1) Analysis of the reaction kinetics of intracellular enzymes can be refined by using FP measurements of the products of fluorogenic substrates in addition to the FI measurements. (2) Subpopulations or individual cells could be classified according to their reaction rates. (3) A specific dependence of FP(t) on type of enzyme substrate is suggested.

The Toronto Lesbian Family Study

Twenty-seven lesbian mothers completed standardized tools chosen to assess current functioning, followed by a video-taped interview. Verbal children were also interviewed. Questions involved perceptions of the mothers' and children's experiences of being homosexual or being raised by homosexual parents, knowledge and fantasies about the donor/father, feelings regarding the role of fathers, parents' experiences of being fathered, legal issues, and development. All mothers were strongly lesbian identified and most were completely "out." All but one mother planned to or had told their children. All mothers planned to reveal donor information at an appropriate age. Many, especially parents of boys, had concerns about lack of a male role model, but none felt this would negatively affect the child's development. Mothers were open to having their child ask questions and even seek out the donor when older. Thirty-one percent of mothers reported a positive relationship with their own father, 42% a father who was present but unavailable or punitive and 27% a completely absent father for large parts of their childhood. Couples divided parenting work based on individual strengths and interests, work schedules and demands. Only two of the couples felt that one of them played a role typical of a father. An aggregate score was compiled for each mother based on the number of negative outcomes in the standardized tools. The mean number of negative outcomes for the mothers was 3.15 (SD = 1.85). Of the six women with 5 or more negative outcomes on the scales, three were single parents and one had lost her partner when her child was two months old. On the CESD, three mothers showed depression levels that were high. The Internal External scale showed 42% of mothers to have an external locus of control. Three mothers scored negatively on the Family Assessment Device. Ninety-two percent of women showed moderate to high self-esteem on the Rosenberg Self-Esteem scale, and the Parenting Stress Index found only 4 women showing enough stress to warrant follow-up. Mothers who reported very negative early experiences of coming out were more likely to report current depressive symptoms (p = .03). All but one child living in two-mother homes identified both mothers as part of their family. Our initial impression is that these are primarily strong families with a variety of parenting skills, stressors and philosophies.

A three-dimensional model of the mouse at embryonic day 9

This paper describes a digital, three-dimensional model of the mouse embryo at E9. The model was made by reconstruction from images of serial histological sections digitally warped to remove distortions and has a resolution of approximately 9 microns. The model can be digitally resectioned in any plane to provide images which resemble conventional histological sections. The main tissues have been identified and delineated by digital painting so that the anatomical components can be visualized and manipulated in 3-D surface- and volume-rendered views. This provides a three-dimensional definition of anatomy that will provide a useful tool for interpreting and understanding spatial data in mouse embryos. The anatomy of the model is discussed where it provides landmarks for interpretation and navigation or where it is unexpected in light of existing descriptions of the E9 mouse embryo. The complete anatomy is not presented in this paper but will be available on CD-ROM. A detailed description of the technical aspects of the construction of the model is included in an appendix. The model is the first of a series that will form the basis for an atlas/database of mouse development. This reconstruction and its associated anatomy are available in a variety of data formats with some supporting software from http:@genex.hgu.mrc.ac.uk/.

Determination of cellular thiol levels in individual viable lymphocytes by means of fluorescence intensity and polarization

Cellular thiol levels regulate lymphocyte proliferation and death and play a significant role in the immune response. Therefore, the ability to analyze the total protein and non-protein thiol compounds and their distribution among individual living lymphocytes is of great importance. A quantitative measurement of intracellular sulphydryl groups in living lymphocytes using the Cellscan mark F (CS-F) cytometer, in conjunction with the probe CMFDA, is described. This technique permits the detection, identification, and study of sub-populations and single cells in a sample of heterogeneous lymphocytes. The Cellscan apparatus is a laser based scanning cytometer incorporating a unique cell carrier which allows repeated, high-precision measurements of fluorescence intensity (FI) and fluorescence polarization (FP) to be made on intact individual living cells under controlled physiological conditions. The discernible effect of fluorophore molecules bound to thiols having a higher FP than free molecules was used to estimate their relative fractions in living lymphocytes. The results were more conspicuous when the ratio between FP measured at two wavelengths (FPR) of the fluorogenic molecules was used for analysis. In addition, the intracellular dynamic changes in the FI, FP and FPR of the fluorescent probe were also monitored. The cellular sulphydryl content of each lymphocyte within a population was recorded by the CS-F, and sub-populations or individual cells were classified according to their thiol levels and their metabolic rates. Changes in thiol concentration were observed following mitogenic activation of peripheral lymphocytes.

The trace and subgrouping of lymphocyte activation by dynamic fluorescence intensity and polarization measurements

Cell activation involves conformational changes of cytosolic enzymes, and/or their regulatory proteins, as well as intracellular matrix re-organization. In this work, these changes were monitored by dynamic measurements of fluorescence polarization in single cells incubated with or without phytohaemagglutinin (PHA), using the Cellscan mark S (CS-S) cytometer. This instrument and the procedure used proved to be a powerful tool for distinguishing subpopulations of cells. Grouping of cells by their staining rates (the time rate of change of the fluorescence intensity) yielded three major subgroups. For each subgroup, the fluorescence depolarization (FDP) induced by the incubation with PHA was measured. The kinetics of the subgroups indicate that the major FDP is contributed by the cells with the lowest staining rate. This FDP is approximately 1.5 times greater than that of a bulk population. It is believed that the analysis of kinetic probing might yield an important and more sensitive method for functional marking of subgroups of cells by their response characteristics.

Reactivity of peripheral blood lymphocytes to oxidized low-density lipoprotein: a novel system to estimate atherosclerosis employing the Cellscan

BACKGROUND

The assumption that atherosclerosis involves an autoimmune response to oxidized LDL (oxLDL) is based on the presence of immunocompetent cells and immunoglobulin deposition in the atherosclerotic lesions by successful immunomodulation of the atherosclerotic process and by inhibition of experimental atherosclerosis by antioxidants. The Cellscan system is a multiparameter laser-based static cytometer that enables repeated monitoring of the fluorescence intensity (FI) and polarization (FP) of individual living cells. Analysis of intracellular fluorescein fluorescence polarization (IFFP) has previously been used to define activated lymphocyte population.

HYPOTHESIS

In this study, the Cellscan apparatus has been used to monitor cellular response to oxLDL in patients with atherosclerosis and in controls.

METHODS

The FI and FP of fluorescein diacetate (FDA)-labeled peripheral lymphocytes were measured following exposure to oxLDL in vitro. Using cluster analysis we were able to identify subpopulations of cells that were characterized by their FI and FP. Forty-two subjects were studied: 22 patients with severe coronary heart disease and 22 control individuals, either healthy or with other diseases.

RESULTS

Fluorescence intensity of fluorescein-labeled peripheral blood lymphocytes (PBL) was markedly decreased upon exposure to high doses (> 25 micrograms/ml) of oxLDL concurrently with an increase in FP. A specific and dose-dependent reduction in FP of the high-intensity cell subpopulations, accompanied by higher FI, was evident in patients with ischemic heart disease upon exposure to low doses of oxLDL (up to 25 micrograms/ml). Maximal depolarization was shown upon triggering with 2 micrograms/ml oxLDL. The polarization ratio (the mean polarization value of the specific cell population with and without activation) obtained for patients' lymphocytes was significantly lower (p < 0.01) than that of the control group (0.936 +/- 0.05 and 1.028 +/- 0.055, respectively).

CONCLUSION

These data suggest that PBL from patients with active ischemic heart disease show an increased reactivity to oxLDL. A 73% positivity rate was found for ischemic heart disease patients compared with 5% in the control subjects. One of the future prospects of this study might be the advent of a simple and rapid noninvasive test that could assess the extent of atherosclerosis, and possibly even the response to therapy, by monitoring the reactivity of PBL to oxLDL.

Cervical cancer screening knowledge and practices among Korean-American women

Cervical cancer is one of the most common cancers of American women. The Papanicolaou (Pap) smear test for cervical screening is a widely used and effective means to reduce the morbidity and mortality rate from cervical cancer through early detection. Despite these benefits, many women have never been screened or are not screened at regular intervals. The purpose of this study was to examine cervical cancer screening knowledge and practices of Korean-American women. The sample consisted of 159 Korean-American women, 40 to 69 years of age. The 1987 Cancer Control Supplement questionnaire was translated into Korean and used to collect data. Twenty-six percent of the respondents never heard of the Pap smear test. Only 34% of respondents reported having had a Pap smear test for screening. The most frequently cited reason for not having had a Pap smear test was absence of disease symptoms. Results indicate that education and usual sources of health care were significant factors related to having heard of or having had a Pap smear test. The findings from this study have important implications for health practitioners and policy makers who serve this ethnic population.

A controlled investigation of bodywork in multiple sclerosis

OBJECTIVE

To determine whether a course of Feldenkrais bodywork would result in significant improvement in physical, mood symptoms and functioning in multiple sclerosis (MS) patients beyond the effects observed using a sham condition (nontherapeutic bodywork).

DESIGN

The bodywork method used was the Feldenkrais method. Subjects were randomly assigned to 1 of 2 groups in a crossover design to control for order effects of treatment. Half of the subjects received 8 weeks of sham sessions followed by 8 weeks of Feldenkrais sessions. The other half of the subjects received Feldenkrais sessions first and then sham. All subjects completed the outcome measures prior to the first course of treatment, in between Feldenkrais and sham, and at study completion.

SETTING

Participants were recruited from a regional MS clinic and were administered bodywork treatment and outcome measures in a bodywork practitioner's office.

SUBJECTS

Twenty individuals with clinically definite MS and disability status scores between 2.0 and 6.0 participated.

OUTCOME MEASURES

Nine-hole pegboard test of hand dexterity, Hospital Anxiety and Depression Scale, MS self-efficacy scale, MS Symptom Inventory, MS Performance Scales, and the Perceived Stress Scale.

RESULTS

The only significant differences were observed for perceived stress and lowered anxiety after Feldenkrais sessions. There were nonsignificant trends toward higher self-efficacy after both Feldenkrais and sham sessions. MS symptoms, levels of functional ability, and upper extremity performance were not affected by Feldenkrais or sham sessions.

A logical analysis of T cell activation and anergy

Interaction of the antigen-specific receptor of T lymphocytes with its antigenic ligand can lead either to cell activation or to a state of profound unresponsiveness (anergy). Although subtle changes in the nature of the ligand or of the antigen-presenting cell have been shown to affect the outcome of T cell receptor ligation, the mechanism by which the same receptor can induce alternative cellular responses is not completely understood. A model for explaining both positive (cell proliferation and cytokine production) and negative (anergy induction) signaling of T lymphocytes is described herein. This model relies on the autophosphorylative properties of the tyrosine kinases associated with the T cell receptor. One of its basic assumptions is that the kinase activity of these receptor-associated enzymes remains above background level after ligand removal and is responsible for cellular unresponsiveness. Using a simple Boolean formalism, we show how the timing of the binding and intracellular signal-transduction events can affect the properties of receptor signaling and determine the type of cellular response. The present approach integrates into a common framework a large body of experimental observations and allows specification of conditions leading to cellular activation or to anergy.

Evaluation of the Periotest as a diagnostic tool for dental implants

The Periotest is examined as a possible replacement for outdated, inconsistent dental implant stability diagnosis tools. The Periotest has the advantage of offering reproducible findings by measuring the levels of subclinical mobility using an ultrasonically vibrating probe. The Periotest is successful in assessing the stability status of an implant, but it can detect the quantity of bony osseointegration only in terminal cases. Radiography proved to be a more sensitive method of determining pericervical bone loss; therefore, periapical radiographs in addition to the Periotest device were found to offer the most reliable assessment of an implant's status.

Senile degeneration and cognitive impairment in chronic schizophrenia

OBJECTIVE

This study was an investigation of the role of Alzheimer-type senile degenerative abnormalities in the cognitive impairment of chronic schizophrenia.

METHOD

The study group comprised 145 deceased elderly institutionalized psychiatric patients: 66 with schizophrenia, 26 with mood disorders, 36 with dementia, and 17 with other psychiatric diagnoses. The comparison group included 16 deceased elderly individuals without neurologic or psychiatric disease. Psychiatric diagnoses and cognitive status were established by standardized review of medical records. Neuritic senile plaques and neurofibrillary tangles were identified immunohistochemically and counted, by investigators blind to clinical information, in standardized regions of each brain.

RESULTS

Of the subjects with schizophrenia, 68% had definite cognitive impairment, but only 8% satisfied neuropathological criteria for Alzheimer's disease. Among the schizophrenia subjects without Alzheimer's disease, definite cognitive impairment was associated with higher levels of plaques and tangles. The schizophrenia subjects without definite cognitive impairment had fewer plaques and tangles than the unimpaired nonpsychiatric subjects.

CONCLUSIONS

Most cases of cognitive impairment in schizophrenia could not be attributed to Alzheimer's disease. An association of mild Alzheimer-type pathology with definite cognitive impairment was unique to schizophrenia. Enhanced sensitivity to the effects of aging on the brain may be a manifestation of diminished cognitive reserve in schizophrenia.

Age differences in entropy: primary versus secondary memory

We report a spatial-memory scanning experiment that was used to measure age differences in entropy. A target grid consisting of four adjacent letters followed by the presentation of a single probe letter was presented on each trial. Half of the trials presented the probe stimulus in the same spatial position was the target letter (i.e., the probe letter was always a member of the positive set), and half of the trials transposed the target letter one, two, or three spaces of the right or left of the original target display position (i.e., different trials). The experiment involved blocks of primary-memory and secondary-memory tasks. Reaction-time and error-rate data, as well as entropy analyses and the fitting of an entropy model (based on Allen, Kaufman, Smith, and Propper, in press) to the empirical data indicated that older adults showed higher entropy levels than young adults. These results are interpreted in a "computational temperature" framework in which older adults' higher computational temperatures result in less efficient spatial, episodic memory functioning.

A molar entropy model of age differences in spatial memory

Two very-short-term-memory, spatial scanning aging experiments were conducted involving a graphics character as a target stimulus. On the probe portion of a trial, the stimulus was presented in the same position as it was on the target portion of the trial (i.e., a same trial) 50% of the time. However, on the remaining 50% of the trials, the probe stimulus was shifted (or transposed) 1, 2, or 3 positions to the right or left of the original presentation (target) position. In Experiment 1, exposure duration was manipulated. In Experiment 2, the number of potential target display positions was manipulated. For both experiments, older adults showed larger transposition distance effects than younger adults for errors. In the past (e.g., P.A. Allen, 1990, 1991), this effect has been attributed to higher levels of internal noise (entropy) in older than younger adults. This research provides converging operations to this contention by using statistical physics methods to rigorously compute the entropy in a molar neural network across age groups. After successfully fitting the statistical mechanics model to the data, the model is proved to have external validity by fitting a simplified version of it to an earlier spatial memory aging experiment reported by P. R. Bruce and J. F. Herman (1986). The results of both traditional reaction time and error rate analyses, as well as the entropy modeling analyses, indicated that older adults exhibited higher levels of entropy than did the younger adults and that this effect appeared to be generalized across processing stage.

Cytokine evaluation in throat infections

Inflammatory cytokines have been shown to play an important role in the pathogenesis of various inflammatory processes. In throat infections, intracellular inflammatory cytokines have been detected from the sites of inflammation. The present study aimed to evaluate serum cytokine levels of patients with throat infections and correlate them to the inflammatory parameters and type of inflammation. Significantly higher inflammatory cytokine levels (interleukin [IL]-6 > 7 pg/mL, IL-1 > 1 beta pg/mL, tumor necrosis factor alpha > 1 pg/mL) were detected in most of the patients as opposed to healthy controls. Clinical parameters of infection (fever > 38 degrees C, leukocytosis > 11,000 white blood cells per cubic millimeter, polymorphonuclear neutrophils > 75%) were significantly correlated with high levels of inflammatory cytokines: mainly IL-6 and tumor necrosis factor alpha, and to a lesser degree with IL-1 beta. No correlation, however, was found between the type of inflammation and cytokine levels. The present study indicates a role of inflammatory cytokines in the pathogenesis of throat infections and the need for an anti-inflammatory and anticytokine therapeutic approach.

Midgut bacteria in Anopheles gambiae and An. funestus (Diptera: Culicidae) from Kenya and Mali

Field studies in Kenya and Mali investigated the prevalence of bacteria in the midguts of malaria vectors, and the potential relationship between gram-negative bacteria species and Plasmodium falciparum sporozoites. Midguts were dissected from 2,430 mosquitoes: 863 Anopheles funestus Giles and 1,037 An. gambiae s.l. Giles from Kenya, and 530 An. gambiae s.l. from Mali. An. funestus had a higher prevalence of gram-negative bacteria (28.5%) compared with An. gambiae collected in Kenya and Mali (15.4 and 12.5%, respectively). Twenty different genera of bacteria were identified by gas chromatography from 73 bacterial isolates from mosquito midguts. Pantoea agglomerans (Enterobacter agglomerans) was the most common species identified. There was no association between gram-negative bacteria in the midgut and P. falciparum sporozoites in field-collected An. gambiae s.l. and An. funestus. However, An. funestus females that harbored gram positive bacteria were more likely to be infected with sporozoites compared with those with no cultivable bacteria or gram negative bacteria in their midguts. Habitat-related variation in the prevalence of diverse types of bacteria in mosquitoes could influence malaria parasite development in mosquitoes and corresponding sporozoite prevalence.

A modified occlusal registration and implant transfer technique

The technique for the transfer of implant and abutment position to a working cast has been hindered by multiple transfers and record reproductions. These serve only to delay completion of the patient's prosthetic requirements. A transfer technique that uses custom impression trays fabricated from surgical templates allows for a single-visit transfer of centric occlusion, vertical dimension, tooth position, and implant or abutment location in one procedure. This streamlines treatment and allows for quicker delivery of final prostheses.

The mouse atlas and graphical gene-expression database

The large amounts of gene-expression data on mouse development are now too extensive to be stored in any format other than that of a database. Furthermore, as this data is intrinsically graphical and as, in the early developmental stages at least, its boundaries do not map directly to those of anatomical tissues, the natural way to store it is in graphical format. We are therefore constructing a database able to handle such graphical gene-expression data by mapping it onto 3-D reconstructions of mouse embryos whose tissues have been delineated. This article reviews the progress that has been made in this project and describes its two major components, CD-ROMs of the 3-D reconstructions to be held on the user's computer and a gene-expression database that will be maintained at a host site, the two being linked over the internet by a complex Java-based interface for submitting data and querying the database.Copyright 1997 Academic Press Limited Copyright 1997Academic Press Limited

Counseling sexually active teenagers treated with potential human teratogens

Adolescents with hemoglobinopathies need daily chelation therapy with drugs which are known or suspected to be teratogenic. The prevention of fetal exposure to such drugs is therefore a major task for health professionals caring for these patients. We describe a pilot program aiming to prevent pregnancy among sexually active adolescents treated with iron chelators in Toronto. Most of them had normal response to GnRH, suggesting endocrinologic fertility, and unlike the literature concerning their healthy peers, all sexually active patients in this study reported use of at least one form of contraception.

Cell activation influences cell staining kinetics

Stimulation of cells has so far been observed, among other methods, by the decrease of the intracellular fluorescein fluorescence polarization (IFFP). It is shown that the rate constant of leakage of the fluorescent marker out of the cells increases with stimulation much more significantly than the polarization decreases; thus it might provide a more sensitive method to observe cells stimulation. It is also shown that due to negligible leakage of the marker out of the cells shortly after initiation of the staining of the cell suspension, the fluorescein fluorescence polarization (FFP) of the cell suspension, is very close to IFFP.