Apoptotic signal transduction: emerging pathways

Apoptosis is a counterbalance to mechanisms of cell proliferation and is critically important in regulation of the immune system, development, and normal tissue homeostasis. Mammalian signal transduction pathways affecting apoptosis are more complex than their counterparts in the nematode Caenorhabditis elegans, a valuable model system that has provided powerful initial insights into key molecules regulating apoptosis. Despite this complexity, substantial progress has been made in recent years towards defining the nature and detail of signalling pathways bringing about apoptosis in mammalian cells. In particular, the identity and precise substrate specificities of a large family of caspase enzymes, implicated as critical components of the apoptotic machinery, have been defined. In addition, the mechanism by which the cell surface Fas receptor mediates induction of apoptosis, via activation of caspases, has recently been elucidated. A prominent role for mitochondria in cell death pathways has also recently emerged, a clear theme being that mitochondria can trigger degradative events by the release of apoptogenic proteins (e.g., cytochrome c) from the intermembrane space to the cytosol. This review focuses on recent progress in these areas and discusses integration of this knowledge in our overall understanding of the processes that control apoptosis.

Clusterin has chaperone-like activity similar to that of small heat shock proteins

Clusterin is a highly conserved protein which is expressed at increased levels by many cell types in response to a broad variety of stress conditions. A genuine physiological function for clusterin has not yet been established. The results presented here demonstrate for the first time that clusterin has chaperone-like activity. At physiological concentrations, clusterin potently protected glutathione S-transferase and catalase from heat-induced precipitation and alpha-lactalbumin and bovine serum albumin from precipitation induced by reduction with dithiothreitol. Enzyme-linked immunosorbent assay data showed that clusterin bound preferentially to heat-stressed glutathione S-transferase and to dithiothreitol-treated bovine serum albumin and alpha-lactalbumin. Size exclusion chromatography and SDS-polyacrylamide gel electrophoresis analyses showed that clusterin formed high molecular weight complexes (HMW) with all four proteins tested. Small heat shock proteins (sHSP) also act in this way to prevent protein precipitation and protect cells from heat and other stresses. The stoichiometric subunit molar ratios of clusterin:stressed protein during formation of HMW complexes (which for the four proteins tested ranged from 1.0:1.3 to 1.0:11) is less than the reported ratios for sHSP-mediated formation of HMW complexes (1.0:1.0 or greater), indicating that clusterin is a very efficient chaperone. Our results suggest that clusterin may play a sHSP-like role in cytoprotection.

Spatial and temporal expression of angiogenic molecules during tumor growth and progression

The growth and metastasis of cancer directly correlates with tumor angiogenesis. A better understanding of the expression of regulatory factors controlling angiogenesis is important in exploiting this process therapeutically. Our present study demonstrates that small tumors (3-4 mm in diameter) express more basic fibroblast growth factor (bFGF) and interleukin 8 (IL-8) than large tumors (> 10 mm in diameter), whereas more vascular endothelial growth factor (VEGF) is expressed in large tumors. Immunostaining showed a heterogeneous distribution of angiogenic factors within the tumor; expression of bFGF and IL-8 was highest on the periphery of a large tumor, where cell division is maximum. VEGF expression was higher in the center of the tumor. In vitro studies demonstrated that sparse cultures of tumor cells expressed higher levels of bFGF and IL-8 than confluent cultures. In contrast, the expression of bFGF and IL-8 was not diminished in tumor cells growing on confluent monolayers of normal cells. VEGF expression was upregulated by cell density irrespective of contact with tumor cells or normal cells. These results demonstrate that the expression of different angiogenic factors in tumor cells can be regulated by their proximity to other tumor cells or host cells.

Evolutionary variation of immunoglobulin mu heavy chain RNA processing pathways: origins, effects, and implications

Immunoglobulins (Ig) can occur in two physical forms, soluble (secreted) and membrane bound. The soluble form is secreted from B cells, and is present in the blood and other fluids where it plays a role as an immune effector molecule. The membrane-bound form of the Ig molecule is inserted into the B-cell membrane, where it serves as a receptor for antigen. The function of the membrane-bound Ig as a receptor for antigen requires additional accessory molecules, the membrane Ig plus accessory molecules are referred to, collectively, as the B-cell receptor (BCR) complex. The secreted and membrane-bound forms of an Ig result from alternative patterns of RNA processing of the primary transcript from the heavy chain gene. IgM is the only class of Ig known to be conserved in all vertebrate species (perhaps exclusive of the agnathan fish). While the structure of the IgM heavy (mu) chain gene has been highly conserved in vertebrate evolution, the patterns of alternative RNA processing of the mu transcript show surprising diversity. In particular, the bony fish (teleosts) produce membrane mu-chain message by a splicing pathway that is quite different from that seen in other vertebrates; it results in the production of membrane IgM that lacks the C mu 4 domain. How this unusual RNA splicing pattern could have evolved and its implications for the function of the BCR in the bony fishes are considered here.

Functional status and well-being in patients with glaucoma as measured by the Medical Outcomes Study Short Form-36 questionnaire

PURPOSE

This study aimed to determine whether patients with glaucoma have different functional status and well-being than patients without glaucoma.

DESIGN

Prospective case-control study.

PARTICIPANTS

The study population was recruited from 2 university-based glaucoma clinical practices and a university-based general ophthalmology clinic and consisted of 121 patients with open-angle glaucoma, 42 with diagnosis of glaucoma suspect, and 135 with no chronic ocular conditions except cataract.

INTERVENTION

Administration of Medical Outcomes Study 36-item short-form survey (SF-36) was performed. Demographic information, medical history, and responses to the SF-36 questionnaire were elicited by an interviewer. Medical record review was performed to obtain clinical examination data and to substantiate the medical and demographic data obtained by the interviewer.

MAIN OUTCOME MEASURES

The SF-36 scores by diagnostic group, demographic characteristics, and medical history were examined. Secondary outcome measures were SF-36 scores in patients with glaucoma by visual field impairment and glaucoma medication use.

RESULTS

Patients with glaucoma consistently had lower scores, control subjects had higher scores, and glaucoma suspects had scores intermediate between the two groups. After adjusting for the possible influence of all the other covariate factors, glaucoma was found to be a strong predictor of lower SF-36 scores.

CONCLUSION

Patients with glaucoma have lower scores, indicating less-functional status, than patients without glaucoma as tested by the SF-36 survey questionnaire.

Evaluation of the contraceptive potential of recombinant human ZP3 and human ZP3 peptides in a primate model: their safety and efficacy

PROBLEM

The unique recognition events that result in the avid binding of mammalian spermatozoa to the surface of the zona pellucida (ZP) are being exploited in the development of contraceptive vaccines. In this study, the safety and efficacy of a vaccination strategy based on the induction of active immunity against purified, glycosylated, recombinant human ZP3 (rhZP3) has been evaluated in a primate model, Callithrix jacchus.

METHOD OF STUDY

Long-term infertility was established after immunization with rhZP3 and the resulting immune sera reacted with rhZP3 on an enzyme-linked immunosorbent assay (ELISA) and immunolocalized exclusively to the outer surface of native ZP on marmoset ovarian sections. However, this contraceptive effect was inevitably associated with the eventual appearance of an ovarian pathology characterized by a depletion of primordial follicles. In an attempt to circumvent this side effect, human ZP3 (hZP3) was epitope mapped and four continuous, immunodominant B-cell epitopes (hZP3(45-64), hZP3(93-110), hZP3(172-190) and hZP3(341-360) were evaluated for contraceptive efficacy in vivo. Using peptide-tetanus toxoid (TT) conjugates to enhance immunogenicity, antipeptide antibodies were raised against these immunogens, which also cross-reacted with rhZP3 on ELISA. In addition, antibodies against hZP3(45-64) and hZP3(172-190) recognized native ZP on marmoset ovarian sections when a microwave technique was used to enhance epitope presentation.

RESULTS

No ovarian pathology was observed after the long-term administration of these peptide immunogens, and fertility was suppressed when compared with TT controls but could not be correlated to the antibody titer.

CONCLUSION

Clearly, further research is required to identify optimal B-cell epitopes that will reliably induce infertility, free from any ovarian pathology.

Isolation, amplification, and sequencing of human mitochondrial DNA obtained from human crab louse, Pthirus pubis (L.), blood meals

The ability to identify individual human hosts based on analyses of blood recovered from the digestive tract of hematophagous arthropods has been a long-term pursuit in both medical and forensic entomology. Blood meal individualization techniques can bring important advancements to studies of vector-borne disease epidemiology. Forensically, these analyses may aid in assailant identification in violent crime cases where blood-feeding insects or their excreta are recovered from victims or at crime scenes. Successful isolation, amplification, and sequencing of human mitochondrial DNA obtained from adult human crab lice fed on human volunteers are reported. Adult lice were removed from recruited volunteers frequenting inner city health clinics. Live lice were killed by freezing and subsequently air dried at ambient temperature. A saliva sample was obtained from each volunteer and served as a DNA reference sample. Volunteers were afforded free, approved pediculosis treatment. Individual lice were subsequently processed using procedures developed for the extraction of mitochondrial DNA from human hair, teeth, and bone. The resulting DNA was amplified by the polymerase chain reaction and sequenced. Our results point to valuable avenues for future entomological research.

Demographic and clinical characteristics of patients with diabetes presenting to an urban public hospital ophthalmology clinic

OBJECTIVE

This study aims to describe the clinical and sociodemographic characteristics of patients with diabetes who are newly presenting to an inner city public hospital eye clinic. This study also aims to determine the prevalence and severity of ocular morbidity in this population at time presentation and to assess the adequacy of the ophthalmic surveillance to which this population was exposed before presentation.

DESIGN

A clinic-based, cross-sectional study.

PARTICIPANTS

A total of 118 consecutive patients with diabetes participated.

METHOD

During a 2-month interval, all patients with diabetes newly presenting to the Los Angeles County King-Drew Medical Center eye clinic were recruited who were at risk for diabetic eye complications according to American Diabetes Association criteria. Each patient underwent a standardized interviewer-administered questionnaire and a comprehensive ophthalmic examination.

RESULTS

Of the 118 patients, 65 (55%) were Hispanic and 51 (43%) were African American. Forty-six percent had a grade school education or less, 91% were unemployed, and 64% had no health insurance. Type two diabetes was predominant (91%), including 24 (22%) of new onset. Thirty-six patients with diabetes (31%) reported duration of diabetes greater than 10 years at time of presentation. At time of presentation, 62% had clinically apparent ophthalmic disease, whereas 40% had advanced ocular disease, including 6.8% of the sample that were legally blind. Sixty-nine patients (58.5%) reported never having had a dilated fundus examination, whereas 31 (63%) of the 49 patients reporting a previous dilated examination were last examined more than 2 years before presentation. Timing of ophthalmic examination was classified as appropriate for 38 patients (32%), marginal for 20 patients (17%), and inappropriate for 60 patients (51%).

CONCLUSION

In the setting of an inner city county hospital eye clinic, where the patient population is predominately minority and of low socioeconomic status, ophthalmic surveillance of high-risk patients with diabetes is inadequate and advanced disease often is present at initial presentation. Strategies must be developed to increase the routine use of eye services within this population.

Apoptosis: unmasking the executioner

The execution phase of apoptosis is comprised of those processes that commit cells to apoptotic death. Many independent studies have implicated mitochondria as playing a critical role in apoptotic execution. The activation of caspase-3 and subsequent late stage degradative events are probably triggered by the release of proteins (such as cytochrome c) from the intermembrane space of mitochondria. The mechanisms responsible for this release are controversial but may include mitochondrial permeability transition and bcl-2-regulated swelling of the mitochondrial matrix. Two theoretical models of execution are discussed. It is important to note that some critical features of these models are largely based on data acquired from cell-free studies. Further studies with intact cells are urgently needed to test the physiological validity of these models.

Identification and characterization of the tumor suppressor p53 in channel catfish (Ictalurus punctatus)

Herein is presented the sequence of a catfish full-length p53 cDNA obtained from a cloned B cell line cDNA library. Southern blot analyses determined that a restriction fragment linked polymorphism (RFLP) existed with PstI among outbred catfish. Western blot analyses demonstrated that, when compared to PBLs, the catfish leukocyte lines express higher levels of p53 protein. Additionally, the results of Western blot analyses and in vitro translation experiments suggest that the catfish leukocyte lines may produce truncated forms of p53 due to internal initiation.

Impaired glucose-stimulated insulin release in islets from adult rats malnourished during foetal-neonatal life

Poor foetal and neonatal nutrition may impair normal pancreatic beta-cell development and predispose to diabetes in later life. We investigate here the nature of the pancreatic beta-cell dysfunction in sucrose-fed adult offspring malnourished during the foetal-neonatal period and examine glucose metabolism and the generation of signals involved in the secretory mechanism. In islets from sucrose-fed previously malnourished rats, rates of glucose utilisation (production of 3H2O) and oxidation (production of 14CO2), at 2, 6 and 10 mM glucose, were not lower than those of controls. ATP concentrations in islets from previously malnourished rats fed sucrose at 2 and 10 mM glucose were similar to those of controls. Glucose-stimulated insulin release was impaired (by 49-55%) in islets from these animals as was the response to keto-isocaproate (by 70%) and tolbutamide (by 70%). Under conditions in which ATP-sensitive K+ channels were clamped open (40 mM K+ and diazoxide), glucose-stimulated insulin release in islets from previously malnourished rats fed sucrose was reduced. These findings show that defects in insulin secretion in islets isolated from previously malnourished animals are located in both ATP-sensitive K+ channel dependent and independent pathways. They do not involve alterations in the early steps of glucose handling in the beta-cell, including glucose metabolism and ATP generation.

Evidence for Jak-STAT interaction in channel catfish lymphoid cells

Herein is described the identification of a putative Jak molecule in the channel catfish. A commercially available polyclonal antibody against human Jak1 was shown to react in Western blot analyses with molecules of approximately 140, 80, and 60 kDa from cell lysates of catfish long-term lymphoid cell lines. It is postulated that the 140 kDa protein is a catfish Jak homolog and the 80 and 60 kDa proteins may represent breakdown products of the 140 kDa protein. Both the 140 and 60 kDa proteins appear to be constitutively tyrosine phosphorylated in channel catfish long-term leukocyte lines. Furthermore, immuno-precipitation studies indicate an association between the Jak molecule and a STAT molecule in cloned T cell lines, and to a much lesser extent in cloned B cell lines, indicative of a possible autocrine stimulatory pathway in catfish long-term T cell lines.

The Glaucoma Symptom Scale. A brief index of glaucoma-specific symptoms

OBJECTIVE

To develop a brief symptom survey specific for persons with glaucoma, the Glaucoma Symptom Scale (GSS).

DESIGN

Cross-sectional study of symptoms, functional impairment, and vision-targeted health-related quality of life among persons with glaucoma.

PATIENTS

A sample of 147 persons with glaucoma among a broad range of treatment categories from 4 tertiary care glaucoma centers and 44 persons without eye disease enrolled from the same 4 centers.

MAIN OUTCOME MEASURES

Participants completed a modified version of the Ocular Hypertension Treatment Study 10-item symptom checklist. Participants also completed 2 vision-specific measures, the National Eye Institute Visual Function Questionnaire and the VF-14. Participants underwent a clinical evaluation, including ocular and medical history, dilated ophthalmic examination, and Humphrey 24-2 automated visual field testing.

RESULTS

The GSS has 2 underlying domains that demonstrate sufficient internal consistency reliability for between-group comparisons. The GSS discriminates well between persons with and without glaucoma. Additionally, tests of association with clinical markers of glaucoma severity support the clinical validity of the measure and tests of association with established vision-targeted measures provide evidence of construct validity.

CONCLUSION

The simplicity, brevity, and psychometric properties of the GSS support its use in clinical practice and research to quantify symptoms in patients with glaucoma and to assist in investigations concerning the effect of glaucoma and treatments.

T-cell receptors in channel catfish: structure and expression of TCR alpha and beta genes

Herein are reported full length cDNA sequences for TCR alpha- and beta-chains of the channel catfish. Included are sequences belonging to four Valpha and six Vbeta families which share hallmarks in common with the Valpha and Vbeta genes of other species. Similar to the situation in other vertebrates, the catfish Calpha and Cbeta sequences exhibit distinct immunoglobulin, connecting peptide, transmembrane and cytoplasmic domains. However, the catfish TCR Calpha and Cbeta regions are shorter than those of mammals and the catfish Cbeta chain lacks a cysteine in its connecting peptide region. Two different catfish Cbeta cDNA sequences were identified, suggesting the existence of either two Cbeta loci or allotypes. Based on Southern blot analyses, each of the catfish TCR gene loci appear to be arranged in a translocon (as opposed to multicluster) organization with multiple V elements and a single or few copies of C region DNA. At the deduced amino acid level, the catfish Cbeta sequence exhibits 42% identity with the Cbeta of Atlantic salmon, 41% identity with the Cbeta of rainbow trout and 26% identity with Cbeta of the horned shark. The catfish Calpha amino acid sequence exhibits 44 and 29% identity with Calpha of the rainbow trout and southern pufferfish, respectively. TCRalpha and beta messages are selectively expressed and rearranged in a catfish clonal cell line that appears to be of the T lineage. This TCR alpha/beta expressing clonal lymphocyte line, designated 28S.1, has T-cell like function in that it constitutively produces a supernatant factor(s) with growth promoting activity. These findings should facilitate functional studies of fish TCRs and T cells in ways not previously possible with other 'lower' vertebrate models.

Characterization of Oct2 from the channel catfish: functional preference for a variant octamer motif

The Ig heavy chain enhancer of the channel catfish (Ictalurus punctatus) has an unusual position and structure, being found in the 3' region of the mu gene and containing eight functional octamer motifs of consensus (ATGCAAAT) and variant sequences. The presence of multiple octamer motifs suggests that an Oct2 homologue may play an important role in driving expression of the Ig heavy chain locus in a teleost fish. To test this hypothesis, two catfish Oct2 cDNAs (alpha and beta) were cloned by screening a catfish B cell cDNA library. Catfish Oct2 alpha and beta isoforms are derived by alternative RNA splicing; as determined by Southern analysis, Oct2 is a single copy gene. In comparisons with mammalian Oct2, the catfish Oct2 isoforms show high sequence conservation in their N-terminal regions and POU domains, but extensive divergence in their C-terminal regions. Catfish Oct2 a and beta are tissue restricted, bind both consensus and variant octamer motifs, and activate transcription in both catfish and murine cells. In contrast, mouse Oct2 activated transcription in mouse but not catfish cells. Catfish Oct2 beta is a more potent transcriptional activator than Oct2 alpha. In transient expression assays, catfish Oct2 beta showed a marked preference for the octamer variant, ATGtAAAT, which occurs twice in the catfish enhancer. Mouse Oct2 also showed increased activity with the variant octamer when tested in mouse B cells. Gel-shift analysis competition assays indicated that catfish Oct2 binds the consensus octamer motif with an apparently higher affinity than it does the variant motif.

Apolipoprotein J (clusterin) induces cholesterol export from macrophage-foam cells: a potential anti-atherogenic function?

Apolipoprotein J (apo J) is a secreted glycoprotein of which the exact function remains a matter for speculation. Apo J has been implicated in such diverse processes as sperm maturation, regulation of complement activation, programmed cell death, tissue remodelling and lipid transport. In this study a possible role for apo J in lipid transport was explored. Mouse peritoneal macrophages were incubated with acetylated low-density lipoprotein (AcLDL) to produce foam cells containing cholesterol and cholesteryl esters. Incubation of the foam cells with physiological concentrations of purified apo J led to a dose-dependent export of cholesterol. The appearance of cholesterol in the medium was associated predominantly with a decline in intracellular cholesteryl esters rather than intracellular free cholesterol. The kinetics of cholesterol release to apo J were similar to apo A-I, an established promoter of cholesterol efflux. Apo J was also shown to induce phospholipid efflux from cells, whereas the cholesterol exported to the medium was associated with the apo J. Studies using foam cells from apo E-null mice showed that the cholesterol exported to the medium was independent of apo E production by the cells. These results present the first evidence that apo J can promote cholesterol efflux from foam cells and indicates that it might have a function in cellular cholesterol homoeostasis in both normal and pathological situations.

Mitogen and growth factor-induced activation of a STAT-like molecule in channel catfish lymphoid cells

This article describes the identification of a putative STAT molecule in the channel catfish (Ictalurus punctatus), the first report of such a molecule in a 'lower' vertebrate. A monoclonal antibody against human STAT6 recognizes an approximately 100 kDa molecule that becomes activated and translocates to the nucleus upon both growth factor and mitogen stimulation of catfish leukocytes. This presumed catfish STAT binds the mammalian interferon-gamma activation site, a known motif of mammalian STAT binding, as shown by electromobility shift assays. Purification of the proteins present in these DNA complexes confirms that the catfish reactive molecule binds to the interferon-gamma activation site sequence. These results suggest that STAT molecules have been highly conserved in vertebrate evolution.

Rapid mitochondrial DNA typing using restriction enzyme digestion of polymerase chain reaction amplicons followed by capillary electrophoresis separation with laser-induced fluorescence detection

The polymorphic control region of mitochondrial DNA (mtDNA) is becoming more commonly used in forensic applications to differentiate among individuals in a population. Two hypervariable regions (HV1 and HV2) are often sequenced following amplification of the mtDNA via the polymerase chain reaction (PCR). More rapid screening assays would reduce both the effort and the expense of comparing two samples. A methodology has been developed that first uses restriction endonuclease digestion of the PCR-amplified mtDNA using RsaI and MnlI and then capillary electrophoresis (CE) to separate and size the PCR-RFLP fragments. This rapid procedure offers an alternative method for screening of polymorphisms in amplified mtDNA samples. In addition, the presence of a T-->C transition at position 16189, which gives rise to the so-called "C-stretch" in HV1, may be predicted from the presence of nonspecific PCR products in the CE results.

Lower fat intake as a predictor of initial and sustained weight loss in obese subjects consuming an otherwise ad libitum diet

OBJECTIVE

To determine what predicts initial and sustained weight loss in subjects consuming a reduced-fat diet ad libitum and the relationship between achieved level of fat intake and weight loss.

DESIGN

Placebo arm of a randomized, controlled trial of a weight-loss drug (dexfenfluramine) in the context of an ad libitum, reduced-fat diet.

SUBJECTS

Thirty-nine subjects (initial mean body mass index +/- standard deviation = 34.9 +/- 3.4; body mass index is calculated as kg/m2) from the placebo group who completed the 9-month study.

INTERVENTION

Dietary assessment and education (month 0) followed by monthly meetings during the single intervention of reducing fat intake (months 1 through 6); one follow-up at 9 months.

MAIN OUTCOME MEASURES

Initial weight loss (first 3 months) and sustained weight loss (over 9-month period).

STATISTICS

Dietary intake, body size, exercise levels, age, and gender were included in multiple regression linear models of initial and sustained weight loss if they were significant independent predictors.

RESULTS

Greater initial weight loss was associated with a greater decrease in fat intake and a lower achieved fat intake at 3 months. Greater sustained weight loss was associated with a lower achieved fat intake, a higher baseline waist circumference, and higher moderate-intensity exercise levels (months 3 and 6). Weight loss occurred in all subjects who reported a fat intake of 40 g/day or less.

APPLICATIONS

The obese persons most likely to achieve and sustain weight loss on an ad libitum, reduced-fat diet are those who can substantially reduce fat intake, those with high initial levels of abdominal fat, and those who undertake regular moderate-intensity exercise. A target of less than 40 g fat per day might be an appropriate goal to ensure weight loss, but dietary underreporting and the difficulty of sustaining very-low-fat intakes need to be considered.

Effects of clusterin overexpression on TNFalpha- and TGFbeta-mediated death of L929 cells

Clusterin is a widely distributed and highly conserved protein for which many functions have been proposed. We used transfected L929 cells to study the effect of clusterin expression on the regulation of cell death signals. We showed that high levels of clusterin expression, about 0.2 pg clusterin secreted per cell per 48 h period, specifically protected L929 cells from TNFalpha-mediated cytotoxicity, while low expression (about 4 fg/cell/48 h) had no effect. However, clusterin expression did not provide transfected L929 cells with protection against death mediated by colchicine, staurosporine or azide. High level expression of clusterin in transfected L929 cells also potentiated the cytotoxicity of TGFbeta. It had previously been shown that exposure of L929 cells to TGFbeta provides protection against TNFalpha. We showed that this protective effect is not additive to that of clusterin expression. One interpretation of this data is that it suggests that clusterin and TGFbeta may act via a common mechanism to provide protection against the cytotoxicity of TNFalpha. Our results indicate that an intracellular action of clusterin protein is responsible for protection against TNFalpha cytotoxicity. Exposure to TNFalpha induces an increase in the level of cell-associated clusterin and specifically in the level of a novel clusterin molecule, which when analyzed under reducing conditions by SDS/PAGE and immunoblotting appears as two closely spaced bands at about 36 and 38.5 kDa. When analyzed under the same conditions, the normal form of intracellular clusterin, which is present with or without exposure to TNFalpha, appears as two poorly resolved bands at about 43-45 kDa. Since the novel form of clusterin is also expressed in cells exposed to TGFbeta, colchicine, staurosporine, and azide, it may result from toxin-induced disruption of processes of normal cellular protein production.

Pelvic mass secondary to polyethylene and titanium alloy wear debris resulting in recurrent deep vein thrombosis

External venous compression can be a cause of deep vein thrombosis (DVT). This is an unusual case of acetabular component failure and resultant polyethylene and titanium alloy wear debris that presented as a pelvic mass and resulted in iliac vein compression and subsequent DVT.

Range of antinuclear antibodies in "healthy" individuals

OBJECTIVE

To determine the range of antinuclear antibodies (ANA) in "healthy" individuals compared with that in patients with systemic lupus erythematosus (SLE), systemic sclerosis (SSc; scleroderma), Sjögren's syndrome (SS), rheumatoid arthritis (RA), or soft tissue rheumatism (STR).

METHODS

Fifteen international laboratories experienced in performing tests for ANA by indirect immunofluorescence participated in analyzing coded sera from healthy individuals and from patients in the 5 different disease groups described above. Except for the stipulation that HEp-2 cells should be used as substrate, each laboratory used its own in-house methodology so that the data might be expected to reflect the output of a cross-section of worldwide ANA reference laboratories. The sera were analyzed at 4 dilutions: 1:40, 1:80, 1:160, and 1:320.

RESULTS

In healthy individuals, the frequency of ANA did not differ significantly across the 4 age subgroups spanning 20-60 years of age. This putatively normal population was ANA positive in 31.7% of individuals at 1:40 serum dilution, 13.3% at 1:80, 5.0% at 1:160, and 3.3% at 1:320. In comparison with the findings among the disease groups, a low cutoff point at 1:40 serum dilution (high sensitivity, low specificity) could have diagnostic value, since it would classify virtually all patients with SLE, SSc, or SS as ANA positive. Conversely, a high positive cutoff at 1:160 serum dilution (high specificity, low sensitivity) would be useful to confirm the presence of disease in only a portion of cases, but would be likely to exclude 95% of normal individuals.

CONCLUSION

It is recommended that laboratories performing immunofluorescent ANA tests should report results at both the 1:40 and 1:160 dilutions, and should supply information on the percentage of normal individuals who are positive at these dilutions. A low-titer ANA is not necessarily insignificant and might depend on at least 4 specific factors. ANA assays can be a useful discriminant in recognizing certain disease conditions, but can create misunderstanding when the limitations are not fully appreciated.

Increasing metastatic potential is associated with induced chromosome 14 translocations in a previously nonmetastatic murine melanoma cell line

The purpose of these studies was to demonstrate causal effects of abnormalities induced in mouse chromosome 14 on tumorigenicity and metastasis using the K-1735 murine melanoma cell line. Because anomalies in chromosome 14 have previously been associated with increases in metastatic potential, we induced chromosome 14 anomalies in a nonmetastatic K-1735 clone 10 cells initially containing two normal copies of chromosome 14 by treatment with mitomycin C. Clone 10-M1, in which a small population of cells (approximately 4%) contained translocations involving chromosome 14, was isolated and injected into athymic nude mice. Unlike the parental C-10 cells, C-10 M1 cells produced experimental lung metastases. Chromosomal analysis of cell cultures established from both subcutaneous tumors and lung metastases indicated that approximately 35% of the cell population contained chromosome 14 anomalies suggesting that this chromosome may play a role in tumor growth and metastasis.

Sequential multiplex amplification: utility in forensic casework with minimal amounts of DNA and partially degraded samples

Since its introduction, PCR has become a widely-used, routine technique in forensic laboratories. A number of PCR protocols that were developed originally are now being replaced by more powerful approaches, particularly those based on multiplex amplification of short tandem repeat (STR) loci. One alternative from of multiplex PCR amplification, called Sequential Multiplex Amplification (SMA), was designed to amplify a single locus and then recover and reuse the remaining genomic DNA as a template for subsequent PCR. The SMA process could be repeated several times. SMA has proven to be useful in typing genomic DNA contained in stored PCR samples and analyzing samples of limited quality and/or quantity for multiple loci. The efficacy of the use of SMA for actual typing of casework samples permitted typing for a second locus 98.11% of the samples considered; 70.75% were typeable for a third locus, and 16.98% for a fourth locus.