Results of taking Master Amino acid Pattern as a sole and total substitute of dietary proteins in an athlete during a desert crossing

Study results show that a 51-year-old female athlete, while taking the Master Amino acid Pattern (MAP) as a sole and total substitute for dietary protein, and performing physical activity, experienced (1) increased body muscle mass, strength, and endurance; (2) decreased body fat mass; (3) greater increase in performance of the nonprevailing muscles compared to the prevailing muscles; (4) improved cardiorespiratory performance; and (5) increased red blood cells, hemoglobin, and hematocrit parameters. It was concluded, confirming previous findings, that use of MAP as a sole and total substitute for dietary protein, in conjunction with physical activity, provides safer, unprecedented optimization of the body's protein synthesis, thereby improving anthropometric characteristics and physical and physiologic performance.

Longevity in vitro of human CD4+ T helper cell clones derived from young donors and elderly donors, or from progenitor cells: age-associated differences in cell surface molecule expression and cytokine secretion

The effectiveness of the adaptive immune system relies upon extensive proliferation of an initially small number of antigen-specific T cells. At the end of a successful response, the majority die by apoptosis and a small minority joins the memory cell pool. Upon re-challenge with antigen, these memory cells must again undergo clonal expansion in order to mediate an effective response. Thus, T cells are subjected to marked proliferative stress which may result in clonal exhaustion due to replicative senescence. In other systems made up of rapidly proliferating cells (e.g. in the gut) individual clones are identical and are replaced at the end of their lifespan by differentiation from a stem cell reservoir. However, because of the unique clonal distribution of antigen receptors on T cells, mere replacement with other T cells is not sufficient to maintain the integrity of the system. Moreover, the very source of new T cells decreases with age (due to thymic involution). Therefore, the adaptive immune system may be uniquely susceptible to the deleterious effects of replicative senescence. Particularly in humans, in vivo studies of the behaviour of individual T-cell clones in the body is difficult. However, T-cell longevity, measured as proliferative capacity in terms of population doublings, can be usefully modelled at the clonal level in vitro. This paper discusses the surprisingly little that is known about the average longevity, variation between clones, and the maximal longevity of human T cells under clonal culture conditions in vitro. From our own studies, we show that average lifespan of human T cells is as little as 17 PD; however, established clones reach 35 PD on average, with maximum longevity generally in the region of 60-80 PD, regardless of the source of the cloned cells. Expression of surface molecules in general did not differ strikingly between young and old donors, but the frequency of clones secreting IL-10, and the amount secreted per clone was higher in the elderly than in the young. Conversely, the frequency of clones secreting IL-6 and the amount secreted per clone was higher in the young.

Microwave-assisted preparation of cyclic ketals from a cineole ketone as potential cosmetic ingredients: solvent-free synthesis, odour evaluation, in vitro cytotoxicity and antimicrobial assays

Some cyclic ketals derived from (+)1,3,3-trimethyl-2-oxabicyclo[2.2.2]octan-6-one were obtained in excellent yields by microwave activation under solvent-free conditions, as a 'green chemistry' procedure. The results obtained using acidic alumina containing 7% p-toluenesulfonic acid, as mineral support, are reported and compared with those obtained by classical methods. The new compounds were tested for their olfactive character and for a potential cosmetic use. In vitro skin cytotoxicity tests were carried out on the most promising compounds, by using NCTC 2544 human keratinocytes as target cells. They all displayed slight cytotoxic effects which were one order of magnitude lower than those found with sodium dodecylsulphate positive control. Two compounds that resulted interesting as toothpaste aromas, were submitted to antimicrobial assays and showed their activity against Pseudomonas aeruginosa, Escherichia coli, Staphylococcus hominis, Propionibacterium acnes and Candida albicans.

Calcein-acetyoxymethyl cytotoxicity assay: standardization of a method allowing additional analyses on recovered effector cells and supernatants

Cytotoxicity assays provide an in vitro evaluation of the lytic activity of NK and T cells against tumors or transformed cells. However, none of these methods allow the recovery of cells or supernatants after the assay. We standardized a microcytotoxicity test using calcein-acetoxymethyl (calcein-AM) dye that requires very small quantities of cells while maintaining the same sensitivity as the traditional (51)Cr assay. The assay is applicable to resting as well as activated human effector cells and uses different targets such as human cell lines that are adherent or growing in suspension and resistant or sensitive. The most important feature of the method is the possibility of recovering cells and supernatants for additional analyses such as phenotyping and evaluation of soluble factors.

Biosynthesis of the cancer-related sialyl-alpha 2,6-lactosaminyl epitope in colon cancer cell lines expressing beta-galactoside alpha 2,6-sialyltransferase under a constitutive promoter

An elevation of beta-galactoside alpha 2,6-sialyltransferase (ST6Gal.I) enzyme activity and an increased alpha 2,6-sialylation of cell membranes are among the most prominent glycosylation changes associated with colon cancer; both modifications correlate with a worse prognosis. In our previous studies, we have frequently observed a discrepancy between the ST6Gal.I level within a colon cancer sample or cell line and the respective level of reactivity with the alpha 2,6-sialyl-specific lectin from Sambucus nigra (SNA). In this study, we have investigated quantitatively the biosynthesis of the sialyl-alpha 2,6-lactosaminyl epitope in two colon cancer cell types expressing the ST6Gal.I cDNA under the control of a constitutive promoter. By measuring the amount of ST6Gal.I mRNA using competitive RT-PCR, the expression of alpha 2,6-sialylated lactosaminic structures with SNA and anti-CDw75 Ig, and the presence of unsubstituted lactosaminic termini by Erythrina cristagalli lectin, we reached the following conclusions: (a) a high proportion of the cell surface lactosaminic termini remains unsubstituted, even in the presence of a very high ST6Gal.I activity. This proportion is strongly dependent on the cell type; (b) ST6Gal.I-transfected colon cancer cells do not express the CDw75 epitope; (c) the level of ST6Gal.I enzyme activity only partially correlates with the mRNA level; (d) despite the control by a constitutive promoter, the ST6Gal.I mRNA is not constantly expressed over time; and (e) a very large portion of the enzyme molecules is secreted in the extracellular milieu. These results indicate that post-transcriptional and post-translational mechanisms play a pivotal role in the control of alpha 2,6-sialylation in colon cancer cells.

Different IL-8 production by T and NK lymphocytes in elderly subjects

A gradual decline in the functional activity of the immune system is described with advancing age. The adaptive immune system seems the most severely affected, but some age-associated modifications also occurs in NK cells. Several studies investigated the age related changes of cytokine production, while little is known about chemokines, whose importance in regulating immune-response becomes even more evident. In this study we investigated whether the ability of T lymphocytes and NK cells to produce IL-8, either spontaneously or after activation, respectively with anti-CD3 monoclonal antibody or interleukin 2 (IL-2) was affected by age. We demonstrated that: (a) T lymphocytes and NK cells spontaneously produced detectable amounts of IL-8; (b) anti-CD3 stimulation of T lymphocytes significantly increased IL-8 production and the increment was more evident in the nonagenarian subjects; (c) similarly, IL-2 stimulation of NK cells rose the production of IL-8 but the amount produced by the old was lower than the one produced by the young group. Because of the co-stimulatory role of chemokines on NK responses and given the demonstrated importance of NK cells in defence against viral infections, the decreased production of IL-8 can be involved in the defective functional activity of NK cells from old subjects.

Randomized controlled trial of 50 and 100 mcg of misoprostol for induction of labor at term

To compare the safety and efficacy of two different regimens of misoprostol for labor induction at term, we conducted a randomized controlled trial on women presenting for induction of labor at > or =37 weeks' gestation. Eligible women were randomized to receive intravaginal misoprostol 50 microg every 4 h or 100 microg every 6 h until any of the following: 1) adequate contraction pattern (3 contractions/10 min); 2) dilatation >3 cm; 3) artificial rupture of membranes; or 4) signs of uterine hyperstimulation. Use of oxytocin during labor was at the discretion of the managing clinician. The main outcome variable considered for analysis was cesarean section rate. Secondary outcome measures were induction to delivery interval and neonatal outcome (Apgar scores, meconium staining, and umbilical artery pH). A total of 58 women were randomized to receive either misoprostol 100 microg (n=26) or 50 microg (n=32). The 100 and 50 microg groups had similar mean Bishop's scores at induction (4.0+/-2.3 vs 4.1+/-2.2, p=0.87), rates of nulliparity, use of epidural anesthesia, and oxytocin augmentation. The number of doses of misoprostol used was similar in the two groups (1.4+/-0.6 vs 1.8+/-1.2). The mean+/-standard deviation time to delivery (hours) (11.9+/-7.3 vs 14.3+/-9.6 h, p=0.30) and cesarean section rate (35% vs 19%, p=0.30, relative risk: 1.8, 95% confidence interval 0.7-5.4) were not different in the 100 vs 50 microg group. Power analysis demonstrated that 132 women would be required in each group to achieve statistical significance in the primary outcome measure (alpha=0.05, beta=0.80). Similarly, rates of 5-minute Apgar scores <7 (4% vs 3%, p=1.0), and of meconium passage (17% vs 25%, p=0.73) were not significantly different between the two groups.

Synthesis of new N,N-disubstituted 4-amino-5,6-dihydro-3-phenyl-2H-thieno[2,3-h]-1-benzopyran-2-ones

The synthesis of some N,N-disubstituted 4-amino-5,6-dihydro-3-phenyl-2H-thieno[2,3-h]-1-benzopyran-2-ones (4a-f), by reaction of phenylchloroketene with a series of N,N-disubstituted (E)-5-aminomethylene-6,7-dihydrobenzo[b]thiophen-4(5)-ones, followed by dehydrochlorination in situ of the primary adducts with DBN, is described. A moderate local anaesthetic activity was observed in the title compounds, particularly in 4e.

Regular moderate intensity physical activity and blood concentrations of endogenous anabolic hormones and thyroid hormones in aging men

BACKGROUND

Physical activity has been reported to affect endocrine function in elderly men.

OBJECTIVE

To establish an association between regular moderate physical activity and endogenous anabolic hormone levels in healthy aging men.

PARTICIPANTS

Twenty four middle-aged (57.4+/-4.7 years) and 24 elderly (68.3+/-2.6 years) physically active men who in the past 10 years had been regularly bicycling during leisure time were compared with 24 middle-aged (57.9+/-4.0 years) and 24 elderly (67.2+/-1.7 years) sedentary men. Groups did not differ for body composition.

MEASUREMENTS

Serum dehydroepiandrosterone sulfate (DHEAS), insulin-like growth factor-I (IGF-1), free testosterone (FT), and thyroid hormone levels were assessed.

RESULTS

In general, elderly men had lower IGF-1 (P<0.001), DHEAS (P=0.013), and triodothyronine levels (P<0.001) than their middle-aged counterparts. Independently of age, however, physically active men had on average higher IGF-1 (P=0.031), DHEAS (P=0.001), and triodothyronine serum levels (P<0.001) than sedentary men. FT and thyroid stimulating hormone (TSH) serum concentrations did not differ across age groups, but physically active men had lower TSH values than sedentary men (P=0.021).

CONCLUSIONS

Our results suggest that, in aging men, regular moderate physical activity is associated with higher levels of IGF-1 and DHEAS levels and with thyroid function alterations.

Elevated plasma homocysteine levels in centenarians are not associated with cognitive impairment

BACKGROUND

Previous reports have shown elevated plasma total homocysteine (tHcy) levels in elderly person with impaired cognition.

OBJECTIVE

To study the association between cognitive status and plasma tHcy levels in centenarians.

DESIGN

Cross-sectional survey.

SETTING

Centenarians living in two northern Italian provinces.

PARTICIPANTS

Thirteen cognitively normal centenarians, ten cognitively impaired not-demented centenarians, and 34 demented centenarians with a clinical diagnosis of Alzheimer's disease (AD).

MEASUREMENTS

Blood levels of homocysteine's biological determinants vitamin B12, folate, and vitamin B6.

RESULTS

Elevated plasma tHcy levels (>17 micromol/l) were common in the general population (77% of normal centenarians, 100% of cognitively impaired not-demented centenarians, 82% of AD centenarians). Demented centenarians had the lowest folate serum levels. Low or borderline vitamin B12 serum levels (<221 pmol/l) and low vitamin B6 plasma levels (<11.7 nmol/l) were found in 33 and 66% of all centenarians independently of cognitive status. Among demented centenarians only plasma tHcy correlated inversely with both serum vitamin B12 and folate. No significant difference was found for plasma tHcy levels among the three diagnostic groups, even after adjusting for B vitamin levels.

CONCLUSIONS

Hyperhomocysteinemia is very common among centenarians, probably due to vitamin deficiencies, but does not seem to be associated with cognitive impairment.

Chemokine production by peripheral blood mononuclear cells in elderly subjects

The function of chemokines in promoting and modulating leukocyte migration is essential for a prompt and efficacious inflammatory response and in host defence against infections. In order to investigate whether this important aspect of immunological response is influenced by ageing, we evaluated the basal levels as well as the ability of peripheral blood mononuclear cells from young and healthy elderly subjects to produce chemokines (IL-8, MCP-1, MIP-Ialpha, RANTES) in response to stimulation with anti-CD3 monoclonal antibody and lipopolysaccharide (LPS), a gram negative bacterial endotoxin. Our main findings are a spontaneous chemokine production; a 20% decrease of proliferative response to anti-CD3 monoclonal antibody accompanied by an age related increase of MIP-Ialpha and RANTES production and by a general increase of all chemokine production compared to unstimulated conditions; a proliferative defect of monocytes to LPS challenge associated with an increase of chemokine production compared to basal conditions with a progressive age-related increase of MIP-lalpha. In conclusion, this study suggests that chemokines could have a compensatory role in balancing the impaired mechanisms involved in 'specific' immune response during ageing. The successful activation of this strategy could contribute to the good performance of immune system so maintaining healthy status in elderly.

Fertility after ectopic pregnancy. Effects of surgery and expectant management

OBJECTIVE

To evaluate the effects of different management strategies for ectopic pregnancy on fertility.

STUDY DESIGN

Retrospective cohort study of 180 consecutive patients who were diagnosed with ectopic pregnancy between September 1988 and December 1995. The fertility rate after ectopic pregnancy treated with surgery was compared with that after expectant treatment. Statistical analysis took into consideration the following confounding variables: history of sterility, infertility, ectopic pregnancy, use of intrauterine device, endometriosis, pelvic inflammatory disease or pelvic surgery prior to ectopic pregnancy, and type of therapy for ectopic pregnancy.

RESULTS

Of the 180 women enrolled in the study, 97 desired conception. The intrauterine conception rate was similar in those initially treated expectantly as in those allocated to primary surgery (63% [31/49] vs. 51% [19/37], P = .37). Successful completion of expectant management was associated with rates of subsequent intrauterine pregnancy similar to those of surgical treatment (including primary surgery and surgery after failure of expectant management) (65% [22/34] vs. 54% [28/52], P = .44). Women undergoing delayed surgery due to failure of expectant management had rates of subsequent intrauterine conception similar to those who underwent primary surgery (9/15 vs. 19/37, P = .79). Several anamnestic factors had a significant and adverse effect on reproductive outcome: history of infertility (P = .01), history of ectopic pregnancy (P = .02) and previous pelvic surgery (P = .001).

CONCLUSION

Expectant and surgical management of ectopic pregnancy had similar subsequent intrauterine conception rates, even when failure of expectant management led to secondary surgery. Gynecologic history can identify the subgroup of patients at higher risk of a poor reproductive outcome.

Interleukin-12 induces efficient lysis of natural killer-sensitive and natural killer-resistant human osteosarcoma cells: the synergistic effect of interleukin-2

Previously we demonstrated that some osteosarcoma cell lines varied greatly in their susceptibility to natural killer (NK) cell lysis in vitro. The expression of CD54 and CD58 adhesion molecules on their surface appeared to influence their vulnerability, and the tumour necrosis factor-alpha (TNF-alpha)-induced positive modulation of CD54 increased osteosarcoma susceptibility in vitro. This study investigated whether peripheral blood mononuclear cells from normal healthy donors could be activated by interleukin (IL)-12 and IL-2, separately or in combination, to lyse osteosarcoma cell lines in vitro, as evaluated by using a microcytotoxicity test. In addition, we analysed (by flow cytometry) whether this function correlated with modifications of the CD2, CD11a, CD11b and CD18 molecules, which are involved in the adhesion of effector cells to the counter-receptors (CD54 and CD58) on osteosarcomas. This study demonstrates that incubation with IL-12 and/or IL-2 triggered NK cell cytolytic activity against osteosarcoma targets and that cytolytic activity was enhanced to a greater extent when lymphocytes were incubated simultaneously with a combination of IL-12 and IL-2. The density of CD18 and CD2 molecules involved in NK adhesion was also up-modulated following cytokine incubation. These changes in the density of adhesion molecules can be involved in the increased lytic activity of effector lymphocytes and in the modification of their binding capacity to osteosarcoma target cells.

[Neuropathies caused by vibrating instruments: clinico-diagnostic study of a group of symptomatic subjects]

In order to evaluate the risk connected with hand-arm vibration exposure and associated disorders of the peripheral nervous system a study was made to assess the relationship between nervous symptoms and laboratory data to determine the kind of disorder. 40 male subjects with hand-arm vibration exposure for more than 5 years and nervous symptoms of the hands for more than 1 year and 2 control groups of non-symptomatic non-exposed subjects were considered. An electroneurophysiological study of the exposed subjects revealed 18 nerve conduction speed changes (12 median nerve, 4 ulnar nerve, 2 median and ulnar nerve), most of which were sensitivity-motor changes; only 9 Carpal Tunnel Syndromes were diagnosed. Some statistically significant differences between exposed subjects with negative results of the electroneurophysiological study and non-exposed subjects were observed. Prolonged vibration exposure seems to induce a hand-arm nerve suffering, initially with a progressive nerve conduction speed change and non-specific symptoms, but subsequently a peripheral nervous system disorder associated or not to a Carpal Tunnel Syndrome may occur.

Isolated fetal choroid plexus cysts: role of ultrasonography in establishment of the risk of trisomy 18

OBJECTIVE

The significance of isolated choroid plexus cysts found by ultrasonographic scan during the second trimester as a marker for trisomy 18 is still debated. We analyzed our data and reviewed the series published in the English-language literature to calculate the likelihood ratio of trisomy 18 in the presence of isolated choroid plexus cysts; that is, the factor by which the individual risk of trisomy 18 is increased in the presence of isolated choroid plexus cysts.

STUDY DESIGN

Likelihood ratios were calculated as ratio of the sensitivity to the false-positive rate. Sensitivity was defined as the rate of isolated choroid plexus cysts detected at midgestation among fetuses with trisomy 18. False-positive rate was defined as the rate of choroid plexus cysts detected at midgestation in the population without trisomy 18. The sensitivities of all published series reporting rates of choroid plexus cysts at the time of the first ultrasonographic examination between 14 and 24 weeks' gestation in populations with trisomy 18 and in low-risk populations were included in the analysis. To these we added all cases of trisomy 18 diagnosed at our institution during the period January 1, 1988, through June 30, 1998, in which prenatal ultrasonographic examination was performed between 14 and 24 weeks' gestation.

RESULTS

The prevalence of second-trimester ultrasonographic detection of isolated choroid plexus cysts among fetuses with trisomy 18 was 6.7% (13/194), whereas that in the population without trisomy 18 was 0.9% (752/79,583). The likelihood ratio associated with isolated choroid plexus cysts was therefore 7.09 (95% confidence interval, 3.97-12.18).

CONCLUSION

The presence of isolated second-trimester choroid plexus cysts increases the base risk of trisomy 18 by a factor of 7.09. This likelihood ratio can be multiplied by the risk calculated according to maternal age to obtain the individual risk of trisomy 18 and thus permit more accurate counseling of the patient.

Critical reappraisal of the utility of sonographic fetal femur length in the prediction of trisomy 21

Measurement of femur length (FL) has been advocated as part of a genetic sonogram for the prediction of Down syndrome (DS). However its predictive ability has been inconsistent. We have studied the diagnostic value of this sonographic parameter in a prospective cohort of women with singleton gestations undergoing genetic sonogram between 14 and 22 weeks because of advanced maternal age or family history of aneuploidies. Genetic sonograms were performed at a mean gestational age of 17.0 weeks (range 14-22). DS was diagnosed in 30 fetuses, while 888 were euploid. Mean+/-SD observed/expected (O/E) values of FL (1.00+/-0.10 versus 0.97+/-0.01, p=0.07) were not significantly different between euploid and DS fetuses. Comparison of the regression equations of FL versus biparietal diameter revealed that while the intercepts were not significantly different between euploid and DS fetuses, the difference in slopes reached significance (p=0.04) suggesting that the predictive ability of FL may increase with advancing gestational age. In addition, a MEDLINE search (National Library of Medicine) was conducted for articles published between 1985 and 1998 on fetal femur length in the prediction of trisomy 21. Review of the published literature on the subject suggests that FL is not a consistent or reliable sonographic predictor of DS. Published thresholds of FL should not be used outside of the Institution from which they originated, and each Institution should establish whether this parameter has predictive ability in its own population.

NK and NK/T cells in human senescence

Natural killer (NK) cells are cytotoxic cells that play a critical role in the innate immune response against infections and tumors. Recent studies on NK cell biology have demonstrated that besides their cytotoxic function, NK cells express cytokine and chemokine receptors and also that they secrete other immunoregulatory cytokines and chemokines, supporting their relevance in the regulation of the immune response by promoting downstream adaptive, Th1 mediated, responses against infections. Immunosenescence is the deterioration of the immune response associated with aging. It is characterized mainly by a defective T cell response, but includes changes in the number and function of other cells of the innate immune system. Age-associated alterations in the number and function of NK cells have been reported. There is a general consensus that a progressive increase in the percentage of NK cells with a mature phenotype occurs in elderly donors associated with an impairment of their cytotoxic capacity when considered on a "per cell" basis. The response of NK cells from elderly individuals to IL-2 or other cytokines is also decreased in terms of proliferation, expression of CD69 and killing of NK-resistant cell lines. Furthermore early IFN-gamma and chemokine production in response to IL-2 or IL-12 is also decreased. However aging does not significantly alter other NK cell functions such as TNF-alpha production or perforin induction in response to IL-2. The percentage of T cells that co-express NK cell markers is also increased in aging. These results indicate that the increase in the number of "classical" mature NK and NK/T cells in aging is associated with a defective functional capacity of NK cells. Low NK cell number or function in elderly individuals is associated with increased mortality risk and increased incidence of severe infections, supporting the role of NK cells in the defense against infections in the elderly.

Effect of micronutrient status on natural killer cell immune function in healthy free-living subjects aged >/=90 y

BACKGROUND

Natural killer (NK) cells play a role in natural immunity against tumor and infected cells. Advanced aging is associated with functional impairment of NK cells and increased susceptibility to nutritional deficiencies.

OBJECTIVE

Our objective was to test whether micronutrient status affects NK cell activity in an older population.

DESIGN

The relations between NK cell variables (percentage of leukocytes and cytotoxicity) and blood concentrations of selected micronutrients were studied in 62 healthy, free-living northern Italian subjects (25 men, 37 women) aged 90-106 y. Anthropometric measurements were also made.

RESULTS

All subjects were well nourished according to age-specific anthropometric norms but many of them had micronutrient deficiencies. The prevalence of micronutrient deficiency was highest for selenium (in approximately 50% of both sexes), zinc (in 52% of men and 41% of women), and vitamin B-6 (in 40% of men and 59% of women), followed by vitamin A (in 16% of men and 27% of women) and vitamin E, vitamin B-12, and folate (each in <10% of both sexes). Ubiquinone-10 status was inadequate in 40% of women and 24% of men (P = 0.02). The percentage of NK cells was associated with serum zinc (men: r = 0.573, P = 0. 007; women: r = 0.373, P = 0.031) and selenium (women: r = 0.409, P = 0.018) concentrations. In women only, NK cell cytotoxicity at different effector-target cell ratios was positively associated with plasma vitamin E and ubiquinone-10 concentrations (P < 0.05). No significant associations with NK cell variables were found for the other measured nutrients.

CONCLUSIONS

The results of this study strengthen the hypothesis that individual micronutrients may affect the number and function of NK cells in old age. The study also confirms the high prevalence of micronutrient deficiencies in healthy and apparently well-nourished persons aged >/=90 y.

Age-related alterations to natural killer cell function

Human natural killer (NK) cells represent a heterogeneous lymphoid population involved in the recognition and lysis of tumor and virally infected cells. NK cells are defined by the expression of the IgG Fc receptor CD16 (FcγRIIIA) and/or CD56. NK cells do not rearrange immunoglobulin (Ig) or T-cell receptor (TCR) genes. Therefore, neither Ig nor the TCR-CD3 complex is expressed at the cell surface, except for the zeta (ζ) chain. Both markers, CD16 and CD56, have been used to analyze age-associated changes in the number of NK cells.

Critical appraisal of the use of nuchal fold thickness measurements for the prediction of Down syndrome

OBJECTIVE

Nuchal fold thickness is the best ultrasonographic predictor of fetal trisomy 21. However, the risk assigned on the basis of the commonly used threshold of nuchal fold thickness >/=6 mm does not take into consideration the significant associations between nuchal fold thickness and gestational age and between maternal age and Down syndrome. We propose a new method of calculating Down syndrome probability that takes into account both gestational age at examination and previously assessed probability of Down syndrome.

STUDY DESIGN

Nuchal fold thickness was measured at ultrasonographic examination at 14 to 22 weeks' gestation without previous knowledge of the fetal karyotype. Nuchal cystic hygromas were excluded from analysis. Statistical analyses included correlation, logistic regression to control for other ultrasonographic predictors of trisomy 21 and for maternal age, receiver operating characteristic curve, and likelihood ratios (defined as the ratio of the sensitivity to the false-positive rate). P <.05 was considered significant.

RESULTS

Mean gestational age at ultrasonography was 16.9 weeks' gestation (range, 14-22 weeks' gestation). Mean (+/-SD) nuchal fold thickness in fetuses with trisomy 21 (4.7 +/- 1.6 mm; n = 29) was greater than in euploid fetuses (3.2 +/- 0.9; n = 780; P <.001). Logistic regression analysis established that nuchal fold thickness was a significant predictor of trisomy 21 independent both of the other ultrasonographic markers and of maternal age (P <.001). Regression analysis showed that nuchal fold thickness was significantly correlated with gestational age among both fetuses with trisomy 21 and euploid fetuses and that the regression line of fetuses with trisomy 21 had a slope similar to that of euploid fetuses. The difference between observed and expected nuchal fold thicknesses on the basis of the biparietal diameter (as a function of gestational age) was used to obviate the confounding effect of gestational age. Differences between observed and expected nuchal fold thicknesses were then used to calculate likelihood ratios. These likelihood ratios could then be multiplied by the individual prior probability to obtain a patient-specific Down syndrome probability.

CONCLUSION

Nuchal fold thickness is correlated with gestational age in both euploid fetuses and fetuses with Down syndrome. Use of the difference between observed and expected nuchal fold thicknesses to determine likelihood ratios allows the calculation of individual posterior probabilities of Down syndrome that take into consideration both gestational age and maternal age.

NK binding capacity and lytic activity depend on the expression of ICAM-1 on target bone tumours

Osteosarcoma cell lines are differently lysed by natural killer (NK) lymphocytes. A critical step in the lytic process is the recognition and attachment of effector to target cells. To determine binding capacity and lytic activity of NK cells, we investigated the distribution and role of ICAM-1, 2 and 3 on two osteosarcoma cell lines (HOS and Saos-2) in basal conditions and after TNFalpha treatment. Modulation of ICAM-1 after TNFalpha treatment modified the binding capacity of NK cells to osteosarcoma target cells. This modulation process appears to play a critical role in determining the susceptibility of these cells to NK-mediated lysis.