A role for surgery in the treatment of relapsed Hodgkin lymphoma

Treatment of Hodgkin lymphoma (HL) has advanced over time, rendering a fatal disease now largely curable. Multiagent chemotherapy regimens, hematopoietic stem cell transplantation, and radiotherapy are the mainstays of care. Surgical intervention is rarely indicated other than for biopsy at diagnosis. However, for patients with recurrent relapsed HL isolated to one anatomical location, refractory to all other therapy, there may be a beneficial role for surgical excision. Herein, we report the surgical management of three relapsed patients with stage IVB HL who were refractory to multiple other therapeutic approaches, who all achieved good event-free survival after operative management.

Single nucleotide polymorphism in IL1B is associated with infection risk in paediatric acute myeloid leukaemia

We evaluated single nucleotide polymorphisms (SNPs) associated with infection risk in children with newly diagnosed acute myeloid leukaemia (AML). We conducted a multicentre, prospective cohort study that included children aged ≤18 years with de novo AML. DNA was isolated from blood lymphocytes or buccal swabs, and candidate gene SNP analysis was conducted. Primary outcome was the occurrence of microbiologically documented sterile site infection during chemotherapy. Secondary outcomes were Gram-positive and -negative infections, viridans group streptococcal infection and proven/probable invasive fungal infection. Interpretation was guided by consistency in risk alleles and microbiologic agent with previous literature. Over the study period 254 children and adolescents with AML were enrolled. Overall, 190 (74.8%) had at least one sterile site microbiologically documented infection. Among the 172 with inferred European ancestry and DNA available, nine significant associations were observed; two were consistent with previous literature. Allele A at IL1B (rs16944) was associated with decreased microbiologically documented infection, and allele G at IL10 (rs1800896) was associated with increased risk of Gram-positive infection. We identified SNPs associated with infection risk in paediatric AML. Genotype may provide insight into mechanisms of infection risk that could be used for supportive-care novel treatments.

Understanding the healthcare experiences of teenaged cancer patients and survivors

BACKGROUND

Despite literature supporting a client and family-centred approach to healthcare delivery in paediatric facilities, there is little information about healthcare delivery from the perspective of teenagers in the oncology setting. The objective of this study is to describe the healthcare experiences of teenagers with cancer.

METHODS

As part of a larger study on teen-centred care delivery in paediatric oncology, a survey included several open-ended questions to learn about the following: (1) what teenagers liked about the cancer care they received; (2) what they disliked about the cancer care received; and (3) what they would include if they could design the perfect cancer centre for teenagers. The survey was completed by 200 teenagers (aged 12-20 years) from three paediatric hospitals in Canada. Answers to these questions were coded and developed into themes and subthemes using a thematic analysis approach.

RESULTS

The number of patients providing answers was 89% for question 1, 63% for question 2 and 68.5% for question 3. Likes and dislikes were conceptualized in terms of four key themes as follows: (1) staff at the treatment centre; (2) the cancer care they received; (3) the treatment centre itself; and (4) social activities. The most common suggestions for the perfect cancer centre included having access to better entertainment, more social opportunities to interact with peers, and a more comfortable environment for themselves and their families.

CONCLUSION

Understanding teenagers' experiences in the paediatric oncology setting provides information that could be used to shape the delivery of healthcare in a way that is tailored to their needs. Further research in this area is required in order to improve existing oncology care.

Caregiving, single parents and cumulative stresses when caring for a child with cancer

BACKGROUND

Single parents whose children have cancer are a marginalized group who report less family centred care, and therefore, less quality cancer care for their children. As such, the aims of this study were to explore how single parents of children with cancer describe their caregiving experiences and to understand their contextual life stressors.

METHODS

A constructivist grounded theory method was used. Qualitative interviews with 29 single parents of children with cancer who were at least 6 months post-diagnosis were recruited between November 2009 and April 2011 from four hospitals across Canada. Line-by-line coding was used to establish codes and themes and constant comparison was used to establish relationships among emerging codes and conceptual themes.

RESULTS

The first set of findings report on caregiving duties including: emotional tasks, informational tasks and physical tasks. The second set of findings report on the contextual picture of parent's lives including their living conditions, their physical and mental health and their family histories of disruption, trauma and disease.

CONCLUSIONS

Single parents caring for children with cancer were found to experience several cumulative stressors in addition to the current strain of caring for a child with cancer. The synergy of these cumulative stresses with the added strain of caregiving for a child with cancer may have long-term health and financial implications for parents. Broad-based policy interventions should focus on relieving the chronic strains associated with being a single parent of a child with cancer.

Family-centred care: a qualitative study of Chinese and South Asian immigrant parents' experiences of care in paediatric oncology

BACKGROUND

Over the past two decades, there is increasing emphasis being placed upon providing family-centred care (FCC) in paediatric oncology settings. However, there is a lack of knowledge of FCC in paediatric oncology from the perspectives of immigrant parents. The purpose of this paper is to describe Chinese and South Asian immigrant parents' experiences of FCC in paediatric oncology settings in Canada.

METHODS

This study adopted a constructivist grounded theory approach. Fifty first generation Chinese and South Asian parents of children with cancer who were at least 6 months post-diagnosis were recruited from six Canadian paediatric oncology centres. Interviews were conducted in English, Cantonese, Mandarin, Urdu, Punjabi or Hindi, and transcribed into English. Analysis involved line-by-line, focused and theoretical coding, and the use of the constant comparison method.

RESULTS

Findings indicated that overall parents were highly satisfied with the care and services they received, and their experiences were reflective of the key elements of FCC. However, there were some areas of concern identified by participants: parents not perceiving themselves as a member of the medical team; inconsistency in the quality and co-ordination of services among healthcare providers; disrespectful and mechanical manner of a few healthcare providers; and parents' discomfort with healthcare providers communicating sensitive health-related information directly with their child.

CONCLUSIONS

In order to successfully provide family-centred services to immigrant parents of children with cancer, better communication of the elements of FCC between healthcare staff and families is needed to negotiate a clear role for the parents as partners of the healthcare team. Moreover, a better understanding of how family relationships are structured in immigrant families will assist healthcare providers to balance the best interests of the child with that of the family as a unit.

The use of parenteral nutrition for the management of PKU patient undergoing chemotherapy for lymphoma: a case report

The metabolic control of phenylalanine levels is a challenge during illness. We present the metabolic management of a 6 year old boy with classical PKU who was diagnosed with stage III intraabdominal Burkit's lymphoma and underwent surgical resection and chemotherapy. The metabolic control during chemotherapy was achieved by the use of parenteral custom made amino acid solution and pro-active adjustment of intake. From the 94 obtained plasma phenylalanine (Phe) levels, 18.4% were above our clinic's recommended upper limit (360 μmol/L, 6 mg/dL) while 52.7% of Phe levels were below the recommended lower limit (120 μmol/L, 2 mg/dL). Phe levels above recommended range were associated with low caloric/protein intake, while levels below recommended range reflected the difficulty in achieving the full prescribed Phe intake. We recommend early institution of custom made amino acid solution with maximum amino acid content and caloric intake to provide optimal phenylalanine control. Administration of phenylalanine via regular intravenous amino acid solution may assist in avoiding low Phe levels when prescribed intake is compromised due to vomiting and other disease related illnesses. Use of custom made, phenylalanine free amino acid solution proved beneficial in the management of blood phenylalanine levels in a PKU patient during chemotherapy for Burkitt lymphoma.

Evaluating family-centred service in paediatric oncology with the measure of processes of care (MPOC-20)

BACKGROUND

In order to evaluate the family-centeredness of paediatric oncology services, a psychometrically sound measure of family-centred services is needed. We performed a comprehensive evaluation of the psychometric properties of the 20-item Measure of Processes of Care (MPOC-20) in parents of children undergoing treatment for cancer at five paediatric oncology centres in Canada.

METHODS

The sample included 411 parents (80% response rate). Exploratory factor analysis was used to determine the best way to group the items into scales. Psychometric tests were used to examine data quality, targeting, internal consistency reliability, within-scale construct validity and known-groups validity.

RESULTS

Exploratory factor analysis identified two factors: a summary measure of family-centred services and a scale measuring activities that meet parents' general informational needs. Scores spanned the entire scale range, floor and ceiling effects were low, and the sample distribution was not unduly skewed. Scales showed acceptable internal consistency reliability (Cronbach's alphas > or =0.93). Known-group hypotheses supported the scales' ability to differentiate between groups hypothesized to differ. Moderate effect sizes were found when MPOC-20 scale scores for parents and for children with good quality of life were compared with those with poor quality of life.

CONCLUSIONS

The MPOC-20 is the only evaluated instrument currently available to measure family-centred services in paediatric oncology. Paediatric cancer programmes can now use this tool to determine parental perception of the extent to which services are family-centred.

Identification of paediatric cancer patients with poor quality of life

The primary objective was to describe predictors of physical, emotional and social quality of life (QoL) in children receiving active treatment for cancer. This Canadian multi-institutional cross-sectional study included children with cancer receiving any type of active treatment. The primary caregiver provided information on child physical, emotional and social QoL according to the PedsQL 4.0 Generic Core scales. Between November 2004 and February 2007, 376 families provided the data. In multiple regression, children with acute lymphoblastic leukemia had better physical health (OR: 0.37, 95% CI 0.23, 0.60; P<0.0001) while intensive chemotherapy treatment (OR: 2.34, 95% CI: 1.42, 3.85; P=0.0008) and having a sibling with a chronic condition (OR: 2.53, 95% CI: 1.54, 4.15; P=0.0002) were associated with poor physical QoL. Better emotional health was associated with good prognosis, less intensive chemotherapy treatment and greater household savings, whereas female children and those with a sibling with a chronic condition had poor social QoL. Physical, emotional and social QoL are influenced by demographic, diagnostic and treatment variables. Sibling and household characteristics are associated with QoL. This information will help to identify children at higher risk of poor QoL during treatment for cancer.

Prevalence of post-thrombotic syndrome following asymptomatic thrombosis in survivors of acute lymphoblastic leukemia

BACKGROUND

Deep vein thrombosis (DVT) is a complication of treatment of acute lymphoblastic leukemia (ALL) in children but little is known about the long-term outcomes of these DVT.

OBJECTIVE

To determine the incidence of post-thrombotic syndrome (PTS) in (i) children with ALL diagnosed with asymptomatic DVT using radiographic testing and (ii) an unselected group of ALL survivors.

METHODS

Cross-sectional study in two populations. Group I comprised children in the Prophylactic Antithrombin Replacement in Kids with ALL treated with L-Asparaginase (PARKAA) study diagnosed with DVT by radiographic tests. Group II consisted of non-selected childhood ALL survivors <21 years. PTS was assessed using a standardized scoring sheet.

RESULTS

Group I: 13 PARKAA patients (median age 12 years) were assessed, and 7 had PTS (54%; 95% CI, 25-81). All patients had collaterals, three also had increased arm circumference. Group II: 41 patients (median age 13 years) with a history of ALL were enrolled, and 10 had PTS (24%; 95% CI, 11-38). All patients had collaterals; five also had increased arm circumference.

CONCLUSION

There is a high incidence of PTS in survivors of childhood ALL with radiographically diagnosed asymptomatic DVT. A significant proportion of ALL survivors develop PTS, indicating previously undiagnosed DVT.

Natural history of arterial and venous thrombosis in children treated with low molecular weight heparin: a longitudinal study by ultrasound

Low molecular weight heparin (LMWH) is efficacious in preventing recurrent thromboembolic events (TEs) in children. The efficacy of LMWH in resolving thrombus in children is, however, unknown and may differ from what has been observed in adults due to known differences in the hemostatic system. We reviewed the ultrasound (US) scanning reports of children treated with LMWH in order to determine the rate and predictors of thrombus resolution. Of 245 children consecutively treated for a non-cerebral TE with enoxaparin (Lovenox, Aventis Pharma Inc., QC, Canada) for at least 5 consecutive days, 190 (78%) had serial ultrasound available for analysis. The mean follow-up time was 7 months (median 3 months, range 3 days to 6.6 years). The rate of complete thrombus resolution was 101/190 (53%, 95% confidence interval 46.2-60.2%). On univariate analysis, arterial and non-occlusive thrombus had an increased rate of resolution when compared with venous and occlusive thrombus. Age at time of TE (neonates vs. non-neonates), location of TE, initial treatment (unfractionated heparin vs. LMWH) and dose of enoxaparin were not related to outcome. On multivariate analysis, type of vessel (vein vs. artery) and occlusion (occlusive vs. non-occlusive thrombus) independently predicted outcome. In children, the rate of complete thrombus resolution is similar to the rate in adults. The clinical significance of residual abnormal vessels, specifically to the occurrence of post-thrombotic syndrome and for the diagnosis of recurrence, needs to be explored in prospective studies.

On the role of aging in carcinogenesis

BACKGROUND

Previously we identified the age at half-total incidence (Age 1/2) for a variety of tumors. In this paper, we compare the Age 1/2 with the age- standardized incidence rate (ASR) in populations that differ a) genetically and environmentally and b) genetically but not environmentally.

MATERIALS AND METHODS

From 1990-era data, we calculated 95% confidence limits about mean values for Age 1/2 and ASR for cancers of the stomach, colon, rectum, lung, female breast, corpus uterus, ovary, testis and prostate.

RESULTS

In populations that differed genetically and environmentally as well as those that differed genetically but not environmentally, we observed large variations in ASR, with little or no variation in Age 1/2.

CONCLUSION

The determinants of ASR are distinct from the determinants of Age 1/2 and likely to be genes that can vary between tissues of tumor origin but are common to all people.

Hydrolytic stability versus ring size in lactams: implications for the development of lactam antibiotics and other serine protease inhibitors

beta-Lactam antibiotics act by acylating a serine hydroxyl group in the catalytic center of bacterial proteases. This requires, among other things, suitable reactivity of the lactam moiety. To evaluate the possible suitability of other lactam systems, kinetic studies were performed using the model reaction of lactams with hydroxide. Following the pace of the reaction by NMR, we found gamma-butyrolactam to be hydrolyzed considerably slower than beta-propiolactam. Surprisingly, delta-valerolactam and beta-propiolactam had the same reactivity. beta-Lactam antibiotics were more reactive than both by approximately a factor of 10(3). Medium-sized lactams were least susceptible to hydrolysis. The study highlights the as yet overlooked six-membered lactam ring as a promising vantage point for the development of new classes of antiinfectives and other serine protease inhibitors.

Putative creatine kinase M-isoform in human sperm is identifiedas the 70-kilodalton heat shock protein HspA2

We previously described a putative creatine kinase M isoform in human sperm that is developmentally regulated and expressed during late spermiogenesis, simultaneous with cytoplasmic extrusion. We have now identified this protein as the testis-expressed 70-kDa heat shock protein chaperone known as HspA2 (the human homologue of mouse Hsp70-2). We have isolated and characterized HspA2 (formerly CK-M) by amino acid sequencing and have localized it by immunocytochemistry to spermatocytes at low levels, to spermatids, and in the tail of mature sperm. The specificity of the CK-M/HspA2 antiserum to HspA2 was demonstrated on immunoblots of one- and two-dimensional SDS-PAGE. In agreement with our earlier biochemical data, immunocytochemistry of testicular tissue indicated that HspA2 is selectively expressed in mature spermatids and in sperm about to be released in the seminiferous tubuli. The identity of HspA2 has been further confirmed by cross-absorption of the mouse HSP70-2 antibody by the HspA2/CK-M fraction, and by identical immunostaining patterns of human testicular tissue using either the anti-CK-M/HspA2 or an anti-mouse Hsp70-2 antisera. During spermiogenesis, both cytoplasmic extrusion and plasma membrane remodeling, which facilitate the formation of the zona pellucida binding site, involve major intrasperm protein transport, which may be chaperoned by HspA2. Accordingly, in immature human sperm, which fail to express HspA2, there is cytoplasmic retention and lack of zona pellucida binding. The present findings provide the biological rationale for the role of the human HspA2 as an objective biochemical marker of sperm function and male fertility, which we have established in earlier clinical studies.

The use of low molecular weight heparin in pediatric patients: a prospective cohort study

OBJECTIVE

Low molecular weight heparins (LMWHs) offer several advantages over standard anticoagulant therapy (unfractionated heparin/warfarin) including predictable pharmacokinetics, minimal monitoring, and subcutaneous administration. Our objective was to determine the safety and efficacy of LMWHs in children.

METHODS

A prospective cohort of children treated with the LMWH enoxaparin (Rhone Poulenc Rorer) was monitored at the Hospital for Sick Children, Toronto, Canada, from March 1994 until July 1997.

RESULTS

There were 146 courses of LMWH administered for treatment and 31 courses for prophylaxis of thromboembolic events (TEs). Clinical resolution of TEs occurred in 94% of children receiving therapeutic doses of LMWH, and 96% of children receiving prophylactic doses of LMWH had no symptoms of recurrent or new TEs. Major bleeding occurred in 5% of children receiving therapeutic doses. Recurrent or new TEs occurred in 1% and 3% of children receiving therapeutic and prophylactic doses of LMWH, respectively.

CONCLUSION

LMWH appears to be efficacious and safe for both management and prophylaxis of TEs. The results of this cohort study justify a randomized controlled trial comparing LMWH with standard therapy for the management of TEs in children.

Mutational analysis of the binding site residues of the bovine cation-dependent mannose 6-phosphate receptor

Mannose 6-phosphate receptors (MPRs) deliver soluble acid hydrolases to the lysosome in higher eukaryotic cells. The two MPRs, the cation-dependent MPR (CD-MPR) and the insulin-like growth factor II/cation-independent MPR, carry out this process by binding with high affinity to mannose 6-phosphate residues found on the N-linked oligosaccharides of their ligands. To elucidate the key amino acids involved in conveying this carbohydrate specificity, site-directed mutagenesis studies were conducted on the extracytoplasmic domain of the bovine CD-MPR. Single amino acid substitutions of the residues that form the binding pocket were generated, and the mutant constructs were expressed in transiently transfected COS-1 cells. Following metabolic labeling, mutant CD-MPRs were tested for their ability to bind pentamannosyl phosphate-containing affinity columns. Of the eight amino acids mutated, four (Gln-66, Arg-111, Glu-133, and Tyr-143) were found to be essential for ligand binding. In addition, mutation of the single histidine residue, His-105, within the binding site diminished the binding of the receptor to ligand, but did not eliminate the ability of the CD-MPR to release ligand under acidic conditions.

On the role of aging in carcinogenesis

We have studied cancer age-incidence patterns for the most common cancers in Connecticut from 1935 to 1994 and in locations throughout the world in the 1975 and 1990 eras. We defined "Age 1/2" as the age at which half the incidence occurs in any given year or era. In every population, we found the cancers could be ranked in the same order according to "Age 1/2", i.e., testis < ovary, corpus uterus, breast < stomach, colon, rectum, prostate. This order of cancers according to "Age 1/2" does not correlate with the order according to age-standardized rates, and "Age 1/2" values exhibit less than 10% the variability of age-standardized rates over time and place. We conclude that the determinant of "Age 1/2" is independent of the determinant of age-standardized rates and suggest that "Age 1/2" is determined by host genes that may vary among tissues of tumor origin but are common to all people.

Central venous catheter related thrombosis in children: analysis of the Canadian Registry of Venous Thromboembolic Complications

BACKGROUND

Central venous lines (CVLs) are frequently associated with deep venous thrombosis (DVT) in children; however, little is known about the epidemiologic characteristics or outcome of CVL-related DVT.

METHODS

The Canadian Childhood Thrombophilia Registry monitored 244 consecutive patients with objectively diagnosed CVL-related DVT for a median duration of 24 months (range 3 months to 7 years).

RESULTS

The incidence of CVL-related DVT was 3.5 per 10,000 hospital admissions. CVL-related DVTs were more frequent in the upper venous system. Ultrasonography or echocardiography were the most commonly used diagnostic tests (n = 183 patients). Venograms were performed on 82 (34%) patients. A variety of therapies were used. Thirty-nine children had pulmonary emboli, but most were not investigated for pulmonary emboli. Nine (3.7%) children died as a consequence of their thromboembolic disease. Recurrent DVT occurred in 16 (6.5%) children, and postphlebitic syndrome occurred in 23 (9.5%) children.

CONCLUSION

Currently no uniform guidelines exist for the prevention and management of CVL-related DVT in children. The frequency and clinical consequences of CVL-related DVTs justify controlled trials of primary prophylaxis in children requiring central venous access.

Characterization of the FET4 protein of yeast. Evidence for a direct role in the transport of iron

The low affinity Fe2+ uptake system of Saccharomyces cerevisiae requires the FET4 gene. In this report, we present evidence that FET4 encodes the Fe2+ transporter protein of this system. Antibodies prepared against FET4 detected two distinct proteins with molecular masses of 63 and 68 kDa. In vitro synthesis of FET4 suggested that the 68-kDa form is the primary translation product, and the 63-kDa form may be generated by proteolytic cleavage of the full-length protein. Consistent with its role as an Fe2+ transporter, FET4 is an integral membrane protein present in the plasma membrane. The level of FET4 closely correlated with uptake activity over a broad range of expression levels and is itself regulated by iron. Furthermore, mutations in FET4 can alter the kinetic properties of the low affinity uptake system, suggesting a direct interaction between FET4 and its Fe2+ substrate. Mutations affecting potential Fe2+ ligands located in the predicted transmembrane domains of FET4 significantly altered the apparent Km and/or Vmax of the low affinity system. These mutations may identify residues involved in Fe2+ binding during transport.

Intranigral or intrastriatal injections of GDNF: effects on monoamine levels and behavior in rats

The present studies were designed to determine whether administration of recombinant human glial cell line-derived neurotrophic factor (rhGDNF) into either the substantia nigra or striatum is capable of augmenting dopamine function of the nigrostriatal pathway in normal rats. Single bolus intracranial injections of rhGDNF at either site increased locomotor activity and decreased food and water consumption and body weight in a dose-dependent manner when compared to vehicle-treated animals. These behavioral responses returned to pre-control levels within 3 weeks post rhGDNF administration. Administration of rhGDNF intranigrally increased dopamine, dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) levels of the ipsilateral substantia nigra at 2 and 6 weeks post injection but had no augmenting effects on dopamine or its metabolites in the striatum. Administration of rhGDNF intrastriatally increased DOPAC and HVA levels of the ipsilateral striatum, although striatal dopamine levels were unchanged. Ipsilateral nigral dopamine levels were increased after intrastriatal injection of rhGDNF. The effects of intracranial rhGDNF were not specific to the nigrostriatal dopamine system, since nigrostriatal serotonin, 5-hydroxyindoleacetic acid (5-HIAA), epinephrine and norepinephrine transmitter levels were altered depending on administration route for rhGDNF and dose. Taken together, these data demonstrate long-lasting neurochemical and behavioral changes which suggest that rhGDNF can augment function in adult rat dopamine neurons. Therefore, rhGDNF may have therapeutic potential for Parkinson's disease.

On the role of aging in carcinogenesis

Correlation coefficients for age-standardized incidence rates between cancers of the stomach, colon, rectum and lung over place (worldwide) and time (in Connecticut) vary from positive to negative values, indicating that these cancers are not caused by common environmental agents. Correlation coefficients for age-incidence patterns (the variation in age-specific rates with age) between these cancers, on the other hand, are all highly positive for both sexes. We conclude that the carcinogenic determinants that vary with age are common to the cancers studied and to both sexes, and distinct from the carcinogenic determinants that vary with place and time. For the cancers studied, incidence rates are negligible until age 30, at which time they increase dramatically and continue to increase at least until age 75. The rate of increase, however, diminishes continuously with advancing age after 30. We suggest that the role of aging in cancer incidence is determined by two components, one responsible for the dramatic rate increase beginning near age 30 and one responsible for the gradual diminution in that rate increase. The former may correspond to the activation of quiescent cells with damaged DNA or to the deactivation of DNA surveillance or repair or to impaired apoptosis, while the latter may correspond to the loss of cell division potential.

Science as cancer prevention for American inner city residents

Eighty parents and guardians of high-risk elementary school children from Hartford, America's fourth poorest city, participated in a 12-week Saturday programme of science and cancer risk reduction while their children participated in a science programme designed to be interesting and fun. The children learned to enjoy biology as innovative recreation. Their parents and guardians learned to appreciate the health risks associated with passive thinking. Cigarette advertisements and misleading food claims were exposed to scientific scrutiny with the result that parents and guardians came to view scientific thinking as a means to protect their children and themselves from cancer. They also learned to reduce cancer risk through proper nutrition. Attendance was excellent and the majority of parents and guardians completing the programme believed they had learned to identify and avoid cancer risks.

The role of aging in cancer incidence: an epidemiological study

Age-specific and age-standardized incidence rates for cancers of the bronchus, stomach, colon, rectum, pancreas, skin, male bladder, and female breast, uterus, and ovary in 1975 were studied in populations throughout the world, and, for bronchus and stomach cancers, over time from 1960 to 1975. The variation in age-specific rates with age was similar for all cancers, as demonstrated by large positive correlation coefficients between age-incidence patterns averaged over all populations. In addition, the age-incidence patterns for bronchus and stomach cancer were similar and essentially invariant over time. The variation in age-standardized rates among the populations was not similar for all cancers, as demonstrated by correlation coefficients that were small in some cases and negative in others. Between bronchus and stomach cancer, age-standardized rates varied in opposite directions from 1960 to 1975. It is obvious, therefore, that the cause for the variation in age-specific rates with age is not related to the cause for the variation in age-standardized rates among populations or over time. The shape of age-incidence patterns for the cancers studied must be determined by a factor that is common to the tissues of tumor origin, and invariant among populations and over time. The intrinsic aging process is the most reasonable candidate for this role.

On the role of aging in cancer incidence: analysis of the skin cancer data

Worldwide age-incidence patterns for melanoma, non-melanoma skin cancer, and the group of all cancers except non-melanoma skin cancer from 1971 to 1976 were normalized for differences in frequency of occurrence and compared. The percentage of total cancer incidence that occurred in young subjects was greater for melanoma and less for non-melanoma skin cancer than for the group of all cancers. The risk for melanoma was apparent by age 15, much earlier than for non-melanoma skin cancer and the group of all cancers. While the risk for non-melanoma skin cancer and the group of all cancers increased continuously with advancing age, the risk for melanoma was constant beyond age 35. We conclude that risk for melanoma is unusually concentrated among the young, and, therefore, that protection from sun exposure is particularly important for this group.

Estimating reference ranges in clinical pathology: an objective approach

Conventional reference ranges evolve from subjective criteria for health and disease. We offer an objective method for distinguishing typical from atypical values by purely statistical criteria. We define typical values as those exhibiting a linear relationship with percentiles on a value versus percentile plot. Identification of percentiles at which deviation from linearity occurs results from calculation of correlation coefficients between values and percentiles over centrally expanding ranges of percentiles. One selects arbitrarily some minimum value for these correlation coefficients, for example, 0.990, as the criterion for deviation from linearity. Values encompassed by these percentiles of deviation constitute an objective reference range. Identification of any correlations between atypical values and symptoms of disease requires clinical follow-up studies.

On the role of aging in cancer incidence: cohort analyses of the lung cancer data

Lung cancer age-specific mortality rates for male and female cohorts born in the United States between 1903 and 1928 increase from age 32 to 52 according to an equation of the form log (mortality rate) = m(age) + b, where m and b are constants. Variation exists among the cohorts in the magnitudes of m and b, but correlation coefficients between age-mortality patterns among all cohorts are highly positive (r greater than 0.98, p less than 0.01), indicating that the form of the equation is similarly appropriate for each cohort. Because cigarette smoking behavior has varied among cohorts and between sexes, we conclude that the form of the equation, i.e., the exponential nature of the lung cancer age-mortality pattern, is independent of environmental carcinogenicity and is best attributed to some aspect of the intrinsic aging process.

On the role of aging in cancer incidence: analysis of the lung cancer data

Age-specific lung cancer mortality rates for U.S. males and females from 1935 to 1978 were normalized to describe the percentage of total mortality in a given era which occurred at a given age interval. Correlation coefficients between age-mortality patterns for various eras were calculated and found to be highly positive. We conclude that the shape of the lung cancer age-mortality pattern has remained remarkably constant despite dramatic changes in the carcinogenicity of the lung environment, and suggest that shape is determined by an invariant influence which is best attributed to some aspect of the aging process.

On the role of aging in cancer incidence: an interpretation of the prostate cancer anomaly with implications for routine screening

Cross-sectional age-incidence patterns for the common male and female cancers in Connecticut were normalized to describe the percentage of total incidence that occurred at each age. The pattern for prostate cancer was atypical--less than the 99% confidence limit from the mean at ages less than 60 and greater than the 99% confidence limit from the mean at ages greater than 75. The available international data on latent carcinoma of the prostate, when normalized as above, resembled the mean male and female cancer patterns in Connecticut and suggested that the atypical behavior of clinical prostate cancer was the result of a lag between the incidence of latent carcinoma and promotion to clinical disease. Confirmation of this suggestion, with the potential to distinguish epidemiologically those latent carcinomas that remain asymptomatic from those that progress to malignancy, awaits routine screening for the latent carcinoma.

The incidence of female cancers: correlations with etiologic implications

Correlation coefficients were calculated between incidence rates for the most frequent female cancers in populations throughout the world. Positive correlations were generally weak, and we conclude that most female cancers do not share a dominant etiologic factor which is inherent in cancer incidence rates. However, most cancers do exhibit similar age-incidence patterns. We also conclude that the determinant of shape in cancer age-incidence patterns is common to most female cancers, internationally invariant, and independent of the determinants of cancer incidence rates. Breast cancer exhibits an unusual age-incidence pattern with a peculiar dependence on the frequency of breast cancer occurrence.

The oral glucose tolerance test: an objective method of interpretation

Oral glucose tolerance test results from a positively-skewed, unimodal distribution were analyzed in such a way as to uncover a natural division within the set of results for each time point. The division in results was obtained from a break in the curve formed when plasma glucose concentration was plotted vs the percentile of the population described by those concentrations. The percentile at which the break occurs separated normal from abnormal glucose concentrations objectively. Previously natural divisions between normal and abnormal glucose concentrations had been found only in bimodal distributions from atypical populations such as the Pima Indians and Nauruans of Micronesia. The glucose concentrations at which separations in our unimodal distribution occur compare well with the available data from the atypical populations. According to one measure of reliability, the 3-h time point was more effective than the more commonly utilized 2-h point in distinguishing normal from abnormal plasma glucose concentration.

On estimating biological variation in diagnostic tests: application to the oral glucose tolerance test

Biological variation (BV) in diagnostic tests can be conveniently estimated by the equation, BV = magnitude of reference limit - reference median magnitude of - 2(SD)A, where "reference limit" refers to either the 2.5th or 97.5th percentile in the reference population, magnitude of indicates absolute value, and (SD)A is the standard deviation of random analytical variation at the reference median. The value of (SD)A is calculated from the equation, (SD)A = (CV)A (reference median)/100, where (CV)A, the coefficient of variation of random analytical variation, is obtained from routine stable quality control material. The BV was calculated for plasma glucose concentration at the time points in the oral glucose tolerance test in an asymptomatic reference population and found to vary in the order: fasting less than 3 hour less than 1/2 hour less than 1 hour less than 2 hour. We present correlation coefficients between subject age and plasma glucose concentration that suggest that BV at the fasting, 1/2, 1, and 2 hour points might be reduced by subdividing reference populations according to subject age.

The incidence of female breast and genital cancer: analysis of the age-dependence

Worldwide age-incidence patterns for female breast and genital cancers were normalized for differences in frequency of tumor occurrence and compared. The percentage of total cancer incidence which occurred in elderly subjects differed between populations but was similar for cancer of the breast, ovary, and corpus uteri within a given population. In addition, cancers of the breast, ovary, and corpus uteri exhibited similar ranges of distribution about the worldwide median incidence at all age intervals and strong positive correlations between crude incidence rates in the populations studied. Despite these and other similarities, breast cancer exhibited a correlation between crude incidence rate and percentage of total incidence which occurred in elderly subjects which was not apparent in the genital cancers. We cannot exclude the possibility that this correlation is coincidental. However the possibility of identifying factors predisposing to or protecting against breast cancer is attractive. The results of this study suggest that such factors would apply to breast but not to genital tissue.

Evaluation of extracranial cerebrovascular disease in the hypertensive patient with ocular pneumoplethysmography at 500 mm Hg

OPG-300 is a reliable noninvasive method of detecting hemodynamically significant stenoses of the internal carotid circulation. An important limitation of the method is that patients with systemic blood pressure greater than 160 mm Hg cannot be studied; in our laboratory this represented 55 percent of the patients referred for testing. The addition of the 500 mm Hg vacuum modification now allows us to reliably test 95 percent of patients referred to our laboratory for evaluation of the extracranial cerebrovascular circulation.