Adaptive evolution of human immunodeficiency virus-type 1 during the natural course of infection

The rate of progression to disease varies considerably among individuals infected with human immunodeficiency virus-type 1 (HIV-1). Analyses of semiannual blood samples obtained from six infected men showed that a rapid rate of CD4 T cell loss was associated with relative evolutionary stasis of the HIV-1 quasispecies virus population. More moderate rates of CD4 T cell loss correlated with genetic evolution within three of four subjects. Consistent with selection by the immune constraints of these subjects, amino acid changes were apparent within the appropriate epitopes of human leukocyte antigen class I-restricted cytotoxic T lymphocytes. Thus, the evolutionary dynamics exhibited by the HIV-1 quasispecies virus populations under natural selection are compatible with adaptive evolution.

Intercontinental spread of a multiresistant clone of serotype 23F Streptococcus pneumoniae

Isolates of serotype 23F Streptococcus pneumoniae with high levels of resistance of penicillin have been commonly recovered in Spain for more than a decade. Recently penicillin-resistant serotype 23F S. pneumoniae strains were also isolated from children attending a day-care center in Cleveland. A number of Spanish and Cleveland isolates were compared by electrophoretic analysis of penicillin-binding protein (PBP) profiles and DNA restriction endonuclease cleavage profiles of the PBP 2X and 2B genes amplified with the polymerase chain reaction and by multilocus enzyme electrophoresis. All strains were identical by these criteria. The findings demonstrate that the Spanish and Cleveland isolates are clonally related and suggest that this antibiotic resistant clone of serotype 23F S. pneumoniae has spread intercontinentally from Spain to the United States.

Horizontal transfer of multiple penicillin-binding protein genes, and capsular biosynthetic genes, in natural populations of Streptococcus pneumoniae

Multiply antibiotic-resistant serotype 23F isolates of Streptococcus pneumoniae are prevalent in Spain and have also been recovered recently in the United Kingdom and the United States. Analysis of populations of these isolates by multilocus enzyme electrophoresis, and restriction endonuclease cleavage electrophoretic profiling of penicillin-binding protein (PBP) genes, has demonstrated that these isolates are a single clone (Muñoz et al., 1991). Here we report studies of non-serotype 23F penicillin-resistant pneumococci isolated in Spain and the United Kingdom. One of the isolates expressed serotype 19 capsule but was otherwise indistinguishable from the serotype 23F clone on the basis of multilocus enzyme electrophoresis, antibiotic resistance profiling, and restriction endonuclease patterns of genes encoding PBP1A, PBP2B and PBP2X, a result which suggests that horizontal transfer of capsular biosynthesis genes had occurred. These same techniques revealed that six other resistant isolates, all expressing serotype 9 polysaccharide capsule, represent a clone. Interestingly, the chromosomal lineage of this clone is not closely related to the 23F clone; however, the serotype 9 and 23F clones harbour apparently identical PBP1A, -2B and -2X genes. To explain these data, we favour the interpretation that horizontal gene transfer in natural populations has distributed genes encoding altered forms of PBP1A, -2B and -2X to distinct evolutionary lineages of S. pneumoniae.

Recombinational exchanges at the capsular polysaccharide biosynthetic locus lead to frequent serotype changes among natural isolates of Streptococcus pneumoniae

Serotype 19F variants of the major Spanish multiresistant serotype 23F clone of Streptococcus pneumoniae have been proposed to have arisen by recombinational exchanges at the capsular biosynthetic locus. Members of the Spanish multiresistant serotype 23F clone and the serotype 19F variants were confirmed to be essentially identical in overall genotype, as they were indistinguishable by REP-PCR, and had identical sequences at three polymorphic housekeeping genes. Eight serotype 19F variants were studied and all had large recombinational replacements at the capsular biosynthetic locus. In all cases, one of the recombinational cross-over points appeared to be upstream of dexB, which flanks one end of the capsular locus, and in six of the variants the other cross-over point was downstream of aliA, which flanks the other end of the locus. In two strains a recombinational cross-over point between the introduced serotype 19F capsular region and that of the Spanish serotype 23F clone could be clearly identified, within cpsN in one strain and within cpsM in the other. The differences in the recombinational junctions and sequence polymorphisms within the introduced capsular genes, suggested that the eight serotype 19F variants emerged on at least four separate occasions. Changes in capsular type by recombination may therefore be relatively frequent in pneumococci and this has implications for the long-term efficacy of conjugate pneumococcal vaccines that will protect against only a limited number of serotypes.

Fluorescence of the purine and pyrimidine bases of the nucleic acids in neutral aqueous solution at 300 degrees K

Fluorescence of adenine, guanine, cytosine, and uracil at room temperature in neutral aqueous solution has been detected by means of a digital signal accumulation technique. Corrected emission and excitation spectra are presented and compared with low-temperature data. The quantum yields are, respectively, 2.6 x 10(-4), 3.0 x 10(-4), 0.8 x 10(-4), and 0.5 x 10(-4) when the bases are excited at their low-energy absorption maxima.

Altered function of insulin receptor substrate-1-deficient mouse islets and cultured beta-cell lines

Insulin receptor substrate-1 (IRS-1) is pivotal in mediating the actions of insulin and growth factors in most tissues of the body, but its role in insulin-producing beta islet cells is unclear. Freshly isolated islets from IRS-1 knockout mice and SV40-transformed IRS-1-deficient beta-cell lines exhibit marked insulin secretory defects in response to glucose and arginine. Furthermore, insulin expression is reduced by about 2-fold in the IRS-1-null islets and beta-cell lines, and this defect can be partially restored by transfecting the cells with IRS-1. These data provide evidence for an important role of IRS-1 in islet function and provide a novel functional link between the insulin signaling and insulin secretion pathways. This article may have been published online in advance of the print edition. The date of publication is available from the JCI website, http://www.jci.org.

The heritability of IQ

IQ heritability, the portion of a population's IQ variability attributable to the effects of genes, has been investigated for nearly a century, yet it remains controversial. Covariance between relatives may be due not only to genes, but also to shared environments, and most previous models have assumed different degrees of similarity induced by environments specific to twins, to non-twin siblings (henceforth siblings), and to parents and offspring. We now evaluate an alternative model that replaces these three environments by two maternal womb environments, one for twins and another for siblings, along with a common home environment. Meta-analysis of 212 previous studies shows that our 'maternal-effects' model fits the data better than the 'family-environments' model. Maternal effects, often assumed to be negligible, account for 20% of covariance between twins and 5% between siblings, and the effects of genes are correspondingly reduced, with two measures of heritability being less than 50%. The shared maternal environment may explain the striking correlation between the IQs of twins, especially those of adult twins that were reared apart. IQ heritability increases during early childhood, but whether it stabilizes thereafter remains unclear. A recent study of octogenarians, for instance, suggests that IQ heritability either remains constant through adolescence and adulthood, or continues to increase with age. Although the latter hypothesis has recently been endorsed, it gathers only modest statistical support in our analysis when compared to the maternal-effects hypothesis. Our analysis suggests that it will be important to understand the basis for these maternal effects if ways in which IQ might be increased are to be identified.

Long-term follow-up of patients immunized with AN1792: reduced functional decline in antibody responders

BACKGROUND

Immunization of patients with Alzheimer's disease (AD) with synthetic amyloid-beta peptide (Abeta(42)) (AN1792) was previously studied in a randomized, double-blind, placebo-controlled phase 2a clinical trial, Study AN1792(QS-21)-201. Treatment was discontinued following reports of encephalitis. One year follow-up revealed that AN1792 antibody responders showed improvements in cognitive measures as assessed by the neuropsychological test battery (NTB) and a decrease in brain volume compared with placebo.

METHODS

A follow-up study, Study AN1792(QS-21)-251, was conducted to assess the long-term functional, psychometric, neuroimaging, and safety outcomes of patients from the phase 2a study 4.6 years after immunization with AN1792. The results were analyzed by comparing patients originally identified as antibody responders in the AN1792 phase 2a study with placebo-treated patients.

RESULTS

One hundred and fifty-nine patients/caregivers (30 placebo; 129 AN1792) participated in this follow-up study. Of the 129 AN1792-treated patients, 25 were classified in the phase 2a study as antibody responders (anti-AN1792 titers > or = 1:2,200 at any time after the first injection). Low but detectable, sustained anti-AN1792 titers were found in 17 of 19 samples obtained from patients classified as antibody responders in the phase 2a study. No detectable anti-AN1792 antibodies were found in patients not classified as antibody responders in the phase 2a study. Significantly less decline was observed on the Disability Assessment for Dementia scale among antibody responders than placebo-treated patients (p=0.015) after 4.6 years. Significant differences in favor of responders were also observed on the Dependence Scale (p=0.033). Of the small number of patients who underwent a follow-up MRI, antibody responders showed similar brain volume loss during the follow-up period subsequent to the AN1792 phase 2a study compared with placebo-treated patients.

CONCLUSIONS

Approximately 4.6 years after immunization with AN1792, patients defined as responders in the phase 2a study maintained low but detectable, sustained anti-AN1792 antibody titers and demonstrated significantly reduced functional decline compared with placebo-treated patients. Brain volume loss in antibody responders was not significantly different from placebo-treated patients approximately 3.6 years from the end of the original study. No further cases of encephalitis were noted. These data support the hypothesis that Abeta immunotherapy may have long-term functional benefits.

Life events, depressive symptoms, and immune function

Because both bereavement and depression have been associated with impaired immune responses, the authors studied two indicators of immune function, natural killer (NK) cell activity and measures of T cell subpopulations, in 37 women who differed in the magnitude of recent life events. Women who had experienced major life changes had lower NK cell activity than women who had few changes. Severity of depressive symptoms in these women was associated with an impairment of NK cell activity, an absolute loss of suppressor/cytotoxic cells, and an increase in the ratio of T helper to T suppressor/cytotoxic cells.

Effect of hormone replacement therapy on bone mass in rheumatoid arthritis patients treated with and without steroids

OBJECTIVE

To assess the effect of hormone replacement therapy (HRT) on bone mass in rheumatoid arthritis (RA) patients treated with and those not treated with steroids.

METHODS

Two hundred postmenopausal women with RA (ages 45-65 years) were randomly allocated to receive transdermal estradiol (hormone replacement therapy; HRT) (50 micrograms daily) or calcium supplementation (400 mg daily) for 2 years. Forty-two of the patients (21%) were taking corticosteroids. Bone mineral density of the lumbar spine (BMDLS) and of the proximal femur (BMDF) was measured at study entry and at 12 months and 24 months.

RESULTS

In the HRT group overall, mean BMDLS had changed by +2.22% (95% confidence interval [95% CI] +0.72, +3.72) and mean BMDF by -0.41% (95% CI -1.89, +1.07) after 24 months. In the calcium group, mean BMDLS changed by -1.19% (95% CI -2.29, -0.09) and mean BMDF by -0.56% (95% CI -2.60, +1.48). Differences between treatment groups were significant for the spine only (P < 0.001). In the 21 HRT-treated patients taking steroids, BMDLS increased by 3.75% (95% CI +0.72, +6.78) and BMDF by 1.62% (95% CI -1.27, +4.51).

CONCLUSION

This study shows that HRT increases spinal BMD and maintains femoral BMD in postmenopausal RA. HRT is also an effective agent in preserving bone mass in patients taking low-dose corticosteroids.

Impaired natural killer cell activity during bereavement

Natural killer (NK) cell activity, a component of the immune surveillance system, was compared in women whose husbands had recently died with that found in age-matched women who had not experienced recent adverse life events. Bereaved women had significantly lower NK activity than women whose husbands were healthy. In a second study, depressive symptoms and NK activity were measured longitudinally in women before and after the death of their husbands. Our results suggest that depressive symptoms, not merely the death of the spouse, are related to a reduction in NK activity during bereavement.

Incidental germline variants in 1000 advanced cancers on a prospective somatic genomic profiling protocol

BACKGROUND

Next-generation sequencing in cancer research may reveal germline variants of clinical significance. We report patient preferences for return of results and the prevalence of incidental pathogenic germline variants (PGVs).

PATIENTS AND METHODS

Targeted exome sequencing of 202 genes was carried out in 1000 advanced cancers using tumor and normal DNA in a research laboratory. Pathogenic variants in 18 genes, recommended for return by The American College of Medical Genetics and Genomics, as well as PALB2, were considered actionable. Patient preferences of return of incidental germline results were collected. Return of results was initiated with genetic counseling and repeat CLIA testing.

RESULTS

Of the 1000 patients who underwent sequencing, 43 had likely PGVs: APC (1), BRCA1 (11), BRCA2 (10), TP53 (10), MSH2 (1), MSH6 (4), PALB2 (2), PTEN (2), TSC2 (1), and RB1 (1). Twenty (47%) of 43 variants were previously known based on clinical genetic testing. Of the 1167 patients who consented for a germline testing protocol, 1157 (99%) desired to be informed of incidental results. Twenty-three previously unrecognized mutations identified in the research environment were confirmed with an orthogonal CLIA platform. All patients approached decided to proceed with formal genetic counseling; in all cases where formal genetic testing was carried out, the germline variant of concern validated with clinical genetic testing.

CONCLUSIONS

In this series, 2.3% patients had previously unrecognized pathogenic germline mutations in 19 cancer-related genes. Thus, genomic sequencing must be accompanied by a plan for return of germline results, in partnership with genetic counseling.

Genetics of resistance to third-generation cephalosporins in clinical isolates of Streptococcus pneumoniae

Resistance to third-generation cephalosporins in a clinical isolate of Streptococcus pneumoniae was shown to be due to the production of altered forms of penicillin-binding proteins (PBPs) 2X and 1A. The cloned PBP2X gene from the resistant strain was able to transform a susceptible strain to an intermediate level of resistance. The resulting transformant could be transformed to the full level of resistance of the clinical isolate using the cloned PBP1A gene from the latter strain. Chromosomal DNA from the resistant strain (and from other resistant strains) could readily transform a susceptible strain to the full level of resistance to third-generation cephalosporins (greater than 250-fold for cefotaxime; greater than 100-fold for ceftriaxone) in a single step (transformation frequency of about 10(-5)). The resistant transformants obtained with chromosomal DNA were shown by gene fingerprinting to have gained both the PBP1A and PBP2X genes from the DNA donor.

Genetic analysis of clinical isolates of Streptococcus pneumoniae with high-level resistance to expanded-spectrum cephalosporins

Streptococcus pneumoniae CS109 and CS111 were isolated in the United States in 1991 and have high levels of resistance to expanded-spectrum cephalosporins (MICs of 8 and 32 micrograms of cefotaxime per ml, respectively). CS109, but not CS111, also showed high-level resistance to penicillin. As both strains expressed the serotype 23F capsule, were very closely related in overall genotype, and possessed identical or closely related mosaic pbp1a, pbp2x, and pbp2b genes, it is likely that they have arisen from a recent common ancestor. High-level resistance to expanded-spectrum cephalosporins was entirely due to alterations of penicillin-binding proteins (PBPs) 1a and 2x, since a mixture of the cloned pbp1a and pbp2x genes from the resistant strains could transform the susceptible strain R6 to the full level of cephalosporin resistance of the clinical isolates. Both PBP1a and PBP2x of these strains were more resistant to inhibition by cephalosporins than those of typical highly penicillin-resistant isolates. The pbp1a genes of CS109 and CS111 were identical in sequence, and the fourfold difference in their levels of resistance to cephalosporins was due to a Thr-550-->Ala substitution at the residue following the conserved Lys-Ser-Gly motif of PBP2x. This substitution was also the major cause of the 16-fold-lower resistance of CS111 to penicillin. The pbp2x gene of CS111, in an appropriate genetic background, could provide resistance to 16 micrograms of cefotaxime per ml but only to 0.12 microgram of benzylpenicillin per ml. Removal of the codon 550 mutation resulted in a pbp2x gene that provided resistance to 4 microgram of cefotaxime per ml and 4 microgram of benzylpenicillin per ml. The Thr-550-->Ala substitution in CS111 therefore appears to provide increased resistance to expanded-spectrum cephalosporins but a loss of resistance to penicillin.

Plasma cortisol and natural killer cell activity during bereavement

Natural killer cell (NK) activity, which is important in the defense against tumors and viral infections, is reduced in women undergoing conjugal bereavement. The relationship between NK activity and plasma cortisol was investigated in three groups of subjects: women who were anticipating the death of their husbands, women whose husbands had recently died, and controls. Bereaved women showed reduced NK activity and increased plasma cortisol levels as compared to controls. Anticipatory bereaved women also showed significant reductions in NK activity, but had levels of plasma cortisol comparable to those of controls. The reduction of NK activity during anticipatory and actual bereavement cannot be explained solely on the basis of increased cortisol secretion.

Atrial natriuretic peptide inhibits mitogen-activated protein kinase through the clearance receptor. Potential role in the inhibition of astrocyte proliferation

The modulation of the activity of mitogen-activated protein kinase (MAPK) by endogenous growth factors or growth inhibitors provides a potential means of regulating cell proliferation. We determined the effect of the endogenous anti-proliferative peptide, atrial natriuretic peptide (ANP), on the ability of MAPK to phosphorylate myelin basic protein. In astrocytes, MAPK activity was significantly stimulated (up to 3-fold) by three known glial mitogens, endothelin-3, platelet-derived growth factor, or phorbol 12-myristate 13-acetate. ANP inhibited by 55-70% the ability of each of these mitogens to activate MAPK. The effects of ANP were equipotent to those caused by C-ANP 4-23, a peptide that specifically binds to the natriuretic peptide clearance receptor. Additionally, both natriuretic peptides caused a 70-80% inhibition of the sodium vanadate-stimulated MAPK activity, complete inhibition of the okadaic acid-stimulated activity, and inhibition of the mitogen-stimulated phosphorylation of MAPK. To understand the potential mechanism by which the natriuretic peptides act, we found that both ANP and C-ANP inhibited the mitogen-stimulated activity of the immediate upstream kinase in the cascade, MAPK kinase (MEK). C-ANP also strongly inhibited the endothelin-3-, platelet-derived growth factor-, and phorbol 12-myristate 13-acetate-induced stimulation of DNA synthesis in the astrocytes, while both okadaic acid and sodium vanadate significantly reversed these anti-proliferative actions. Our results identify ANP as a peptide hormone that inhibits growth factor-stimulated MAPK. These data suggest that the ability of the natriuretic peptides to inhibit MAPK may be important for their anti-growth actions. This effect likely occurs via the inhibition of upstream kinase(s), including MEK, uniquely resulting from ligand binding to the natriuretic peptide clearance receptor.

A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

A structured interview version of the Hamilton Depression Rating Scale: evidence of reliability and versatility of administration

A structured interview version of the Hamilton Depression Rating Scale (SI-HDRS) is described. Data are presented in support of its inter-rater and internal consistency reliability. SI-HDRS scores were reproducible by trained interviewers who lacked psychiatric backgrounds. Test-retest scores of a subset of patients who were interviewed twice (once in person and once by telephone) were highly correlated. Scores on the SI-HDRS did not differ between face-to-face and telephone administration groups, controlling for demographic factors, depression-specific indicators, and social and physical functioning. Since the SI-HDRS does not require a face-to-face interview by an experienced clinician, this instrument can be used economically in large-scale, community-based research projects.

A randomised controlled trial of the effect of hormone replacement therapy on disease activity in postmenopausal rheumatoid arthritis

OBJECTIVE

To assess the effects of hormone replacement therapy (HRT) on disease activity in postmenopausal rheumatoid arthritis (RA).

METHODS

Two hundred postmenopausal outpatients (aged 45-65 years) were admitted into a single blind randomised placebo controlled trial of transdermal oestradiol (50 micrograms daily) over six months. Patients continued with routine antirheumatic medications. Compliance with HRT was monitored using serum oestradiol (E2) levels. Disease activity was monitored at entry, three and six months using erythrocyte sedimentation rate (ESR), articular index (AI), visual analogue pain scale (VPS) and early morning stiffness (EMS).

RESULTS

Ninety one and 77 patients completed six months treatment with placebo and HRT respectively. There were no significant differences in baseline characteristics between the groups and no overall effects of treatment. However, 35 patients (41.6%), who completed HRT, failed to achieve serum E2 levels > 100 pmol/l at either three or six months and were considered 'poor-compliers'. In the remaining HRT 'compliers' (58.4%) there were significant improvements after six months in articular index (28.9%; p < 0.01) and pain score (21.7%; p < 0.05) compared with placebo, as well as reductions in ESR (8.9%; NS) and morning stiffness (25.2%; NS). Comparisons between HRT 'compliers' and 'poor-compliers' confirmed significant improvements in articular index (p < 0.001), pain score (p < 0.05) and morning stiffness (p < 0.001) in the 'compliers'.

CONCLUSIONS

This study did not show an overall effect of HRT on disease activity when used as an adjunct therapy in postmenopausal patients. A subgroup of patients, who had greater increments in serum E2 whilst taking HRT, demonstrated improvements in some parameters of disease activity, suggesting a potential beneficial effect with good compliance and higher dose HRT. Most importantly, in the treatment of RA associated bone loss, HRT can be prescribed without fear of a disease flare up.

Familial Mediterranean fever: high gene frequency among the non-Ashkenazic and Ashkenazic Jewish populations in Israel

Familial Mediterranean fever (FMF) is an autosomal recessive recurrent episodic inflammatory disorder that occurs with high frequency in certain populations in the Mediterranean area. Using extended pedigree data of 90 FMF probands, we calculated the FMF gene frequency in various ethnic groups in Israel by analyzing the frequency in a total of 2,312 first cousins. The heterozygote frequencies were as follows: 1:4.9 (0.2 +/- 0.06) for the Libyan subgroup, 1:6.4 (0.16 +/- 0.03) for the other North African countries subgroup, 1:13.3 (0.07 +/- 0.04) for the Iraqi subgroup, 1:11.4 (0.09 +/- 0.06) for the Ashkenazic subgroup, and 1:29.4 (0.03 +/- 0.03) for the remaining ethnic groups. The observed number of affected parents and offspring of the probands was in agreement with the estimated gene frequency. Thus, the FMF gene frequency is very high in all Jewish ethnic groups in Israel, especially those originating in North African countries. This also explains the parent-to-off-spring transmission of FMF reported in North-African Jews.

Use of serial carcinoembryonic antigen and CA 15.3 assays in detecting relapses in breast cancer patients

To evaluate the utility of CEA and CA 15.3 for early diagnosis of recurrence, serial serum determinations of both antigens were performed in 1023 patients (follow-up: 1-10 years, mean 6.2 years) with primary breast cancer (CA 15.3 in 533 cases) and no evidence of residual disease (NED) after radical treatment (radical mastectomy or simple mastectomy and radiotherapy). 246 patients developed metastases during follow-up.

RESULTS

CEA and CA 15.3 were elevated ( > 10 ng/ml or > 60 U/ml, respectively) prior to diagnosis in 40% (98/246) and 41% (37/91) of the patients with recurrence, with a lead time of 4.9 +/- 2.2 and 4.2 +/- 2.3 months, respectively. When patients with locoregional recurrences were excluded, sensitivity improved to 46% (CEA) and 54% (CA 15.3), and to 64% with both tumor markers (CEA and/or CA 15.3). Higher levels of both CEA and CA 15.3 at diagnosis of recurrence, higher sensitivity in early diagnosis of relapse, and a higher lead time were found in ER+ (CEA) or PgR+ patients (CA 15.3) than in those that were negative for these receptors in the primary tumor (p < 0.001). Specificity of the tumor markers was 99% for both CEA (777 NED patients) and for CA 15.3 (444 NED patients), respectively. In conclusion, CEA and CA 15.3 are useful tools for early diagnosis of metastases, mainly in those patients with ER+ or PR+ tumors.

Value of postoperative surveillance after radical surgery for colorectal cancer: results of a cohort study

PURPOSE

Early detection of recurrence after curative resection for primary colorectal cancer should improve patients' prognosis. However, the usefulness of postoperative surveillance programs has not been clarified yet. The present cohort study was aimed at assessing the effectiveness of systematic follow-up in patients with colorectal cancer who were operated on for cure, regarding both rate of tumor recurrence amenable to curative-intent surgery and rate of survival.

METHODS

One hundred ninety-nine colorectal cancer patients who underwent radical primary surgery were followed according a well-defined postoperative surveillance program, which consisted of laboratory studies (including serum carcinoembryonic antigen assay) every three months, physical examination and abdominal ultrasound or computed tomography every six months, and chest radiograph and total colonoscopy once per year. Cohorts were defined according to patients' compliance with the proposed follow-up program. A multivariate regression model was constructed to predict survival.

RESULTS

One hundred forty patients were considered to be compliant with the surveillance program, whereas the remaining 59 patients occasionally attended follow-up investigations or did not comply at all. Although there were no differences in the overall recurrence rate (38 vs. 41 percent; P = 0.52), curative-intent reoperation was possible in 18 patients (34 percent) of those with tumor recurrence in the compliant cohort but in only 3 patients (12 percent) in the noncompliant cohort (P = 0.05). Similarly, the probability of survival was higher in the compliant cohort, both regarding overall (63 vs. 37 percent at 5 years; P < 0.001) and cancer-related (69 vs. 49 percent at 5 years; P < 0.02) rates. Cox regression analysis disclosed that only a more advanced TNM stage (odds ratio, 8.17; 95 percent confidence interval, 1.13-59.29) and noncompliance with the postoperative surveillance program (odds ratio, 2.32; 95 percent confidence interval, 1.50-3.60) had an independent negative impact on survival.

CONCLUSION

Systematic postoperative surveillance in patients with colorectal cancer who were operated on for cure increases both the rate of tumor recurrence amenable to curative-intent surgery and rate of survival.

Velocity of sarcomere shortening in rat cardiac muscle: relationship to force, sarcomere length, calcium and time

The relation between force and velocity was determined in sixteen trabeculae of rat right ventricle as a function of time during a twitch, of sarcomere length and of external Ca2+ concentration, [Ca2+]o. The trabeculae were studied in modified Krebs-Henseleit solution at 25 degrees C. Force was measured with a semiconductor strain gauge. Sarcomere length was measured with a laser diffraction system. A servomotor system was used in which control could be switched between sarcomere length, muscle length and force. Force-velocity relations were derived from load clamps and from contractions in which sarcomere length was initially held constant followed by a quick release and slower release of the sarcomeres at controlled velocity. Force-velocity relations were fitted by Hill's equation (Hill, 1938), (Po-P) b = (P+a) V, where P = force, V = velocity, Po = isometric force in mN/mm2 and a and b are constants. For [Ca2+]o = 2.5 mM, with both interventions the values (mean +/- S.D.) were: b = 1.00 +/- 0.45 micron/s; a = 9.52 +/- 5.60 mN/mm2; Vo measured = 13.6 +/- 3.0 micron/s; Vo calculated = 13.4 +/- 3.4 micron/s; Po measured = 96.5 +/- 25.0 mN/mm2; Po calculated = 119.3 +/- 34.5 mN/mm2. Vo rose with [Ca2+]o to a maximum at [Ca2+]o = 1.2 mM when Po was about 50% of maximum, while Po rose with [Ca2+]o to a maximum at above 2.5 mM. Vo rose with time during the twitch to a maximum at 25 ms following onset of contraction; Po was then about 50% of the maximum that was obtained at 120 ms. Vo increased with sarcomere length from zero at a sarcomere length of 1.6 micron to a maximum at 1.85 micron. Between 1.85 micron and 2.3 micron, Vo was constant. At 1.85 micron, Po was about 60% of maximum Po. These results are compatible with the hypothesis that Vo is more sensitive than Po to the amount of Ca2+ bound to the contractile proteins, and that Vo reaches a maximal value with an amount of Ca2+ bound to the contractile proteins at which Po has obtained only about 50% of its maximal value.