Head and neck cancers volume reduction: should we reduce our prophylactic node radiation to spare the antitumor immune response?

Radiotherapy for locally advanced head and neck cancer classically include large prophylactic node volume. However, the use of these large volumes can be responsible for significant toxicity. Furthermore, the disappointing results of radioimmunotherapy combinations in head and neck tumors raise concerns about radiotherapy's potential negative impact on the immune response when large lymph node volumes are treated. Besides, in other tumor locations, such as lung cancers, the volumes of elective irradiation have been considerably reduced, with the same local control as before. This opinion piece reviews the current state of radiation volumes in head and neck cancers, the rationale for these volumes, the potential impact of radiotherapy on immune response, and the volume changes that would improve the efficacy of radioimmunotherapy combinations.

Predicting the distribution of whey protein fouling in a plate heat exchanger using the kinetic parameters of the thermal denaturation reaction of ß-lactoglobulin and the bulk temperature profiles.

Fouling of plate heat exchangers (PHE) is a severe problem in the dairy industry, notably because the relationship between the build-up of protein fouling deposits and the chemical reactions taking place in the fouling solution has not yet been fully elucidated. Experiments were conducted at pilot scale in a corrugated PHE, and fouling deposits were generated using a model ß-lactoglobulin (ß-LG) fouling solution for which the ß-LG thermal denaturation reaction constants had been previously determined experimentally. Then 18 different bulk temperature profiles within the PHE were imposed. Analysis of the fouling runs shows that the dry deposit mass per channel versus the ratio R=kunf/kagg (with kunf and kagg representing, respectively, the unfolding and aggregation rate constants computed from both the identification of the ß-LG thermal denaturation process and knowledge of the imposed bulk temperature profile into the PHE channel) is able to gather reasonably well the experimental fouling mass data into a unique master curve. This type of representation of the results clearly shows that the heat-induced reactions (unfolding and aggregation) of the various ß-LG molecular species in the bulk fluid are essential to capture the trend of the fouling mass distribution inside a PHE. This investigation also illustrates unambiguously that the release of the unfolded ß-LG (also called ß-LG molten globule) within the bulk fluid (and the absence of its consumption in the form of aggregates) is a key phenomenon that controls the extent of protein fouling as well as its location inside the PHE.

Trypanosoma cruzi nucleoside diphosphate kinase 1 ( TcNDPK1) has a broad nuclease activity.

Here, we present the characterization of a trypanosomatid nucleoside diphosphate kinase (TcNDPK1) exhibiting nuclease activity. This is the first identification of a NDPK with this property in trypanosomatid organisms. The recombinant TcNDPK1 protein cleaves not only linear DNA, but also supercoiled plasmid DNA. Additionally, TcNDPK1 is capable of degrading Trypanosoma cruzi genomic DNA. ATP or ADP did not affect the nuclease activity, while the absence of Mg2+ completely inhibits this activity. NDPK and nuclease activities were inhibited at the same temperature, suggesting the presence of related catalytic sites. Furthermore, phenogram analysis showed that TcNDPK1 is close to Drosophila melanogaster and human NDPKs. The unspecific nuclease activity could suggest a participation in cellular processes such as programmed cell death.

Analysis of a territorial approach to the delivery of nursing home care services based on historical data.

We analyze a territorial approach to deliver nursing homecare services to a territory public health. We present the case of the CSSS assigned to Côte-des-Neiges, Métro center and Parc Extension, specifically the case of the Côte-des-Neiges site (CLSC CDN), where a territorial approach is used since 1980. We first give an historical comparison of patient visits delivered in 1998-1999 and in 2002-2003. We follow with an in-depth analysis of the home services delivered in 2002-2003 to determine whether or not the territorial approach can well support the changing needs of the population. We conclude that the territorial approach to deliver homecare nursing services does not sufficiently support fluctuations in population needs for services. Not only is it difficult to predict these fluctuations, but it is difficult to accurately quantify the true needs for services since the availability of nursing services tends to determine the services actually delivered. In sectors of the territory where resources are more scarce (based on previous population needs analyses) or demand for services is greater, the result is work overload for the nursing staff. In addition, this results in service delivery inequities across the entire territory. Therefore, a more dynamic assignment of clients to the nurses based on each nurse's work load and case load rather than based on the geographic location of clients is worth the extra administrative time in case assignment to ensure a more equitable case load attribution between nurses as well as less inequities between clients in terms of service delivery considering their needs.

Population growth impacts of zero net international migration.

"In a country such as the United States, the contribution of net international migration to overall population change overshadows the contribution of natural increase.... Some analysts have assumed that if the same number of people leave and enter the country each year, then the effect of net international migration will be zero. This article examines that assumption and shows that it is fallacious. Examining the direct, indirect, total, and negative demographic impacts of zero net international migration through simulations with demographic data, we demonstrate that zero net international migration is not the same and therefore does not have the same demographic results and implications as zero international migration. We conclude that zero net international migration should not be confused with zero international migration."

Zero net international migration: what does it really mean?

"The idea of ¿zero net migration' is gaining increasing currency. It has been assumed that if there is balance between the number of immigrants and emigrants, migration will have no impact on a country's population size. However, this article demonstrates that zero net migration is not necessarily the same as zero migration, and can result in a higher population than would have occurred without any migration at all." The examples of Germany and the United States are presented.

Two methods of haploidization in pear, Pyrus communis L.: greenhouse seedling selection and in situ parthenogenesis induced by irradiated pollen.

Seedlings of 12 crosses involving pear varieties or hybrids were observed for the presence of haploid plants. On the basis of phenotypic characteristics, 17 plants corresponded to the haploid condition and, of these, 12 were determined by chromosome counting to be haploid (2n=x=17). In addition, and in order to induce in situ parthenogenesis, several pear varieties were pollinated with a selected clone carrying a homozygous dominant marker gene for the colour of red. This pollen had previously been irradiated with γ-rays of cobalt 60 at 0, 200, 250 and 500 Grays. The immature embryos were cultured in vitro, whereby 1 haploid and two mixoploid plants were obtained. Numerous diploid plants with the maternal phenotype were also obtained, and their genetic origin was subsequently studied by means of isozyme analysis.

Phase 1 study of recombinant human CD4-immunoglobulin G therapy of patients with AIDS and AIDS-related complex.

The safety and pharmacokinetics of recombinant CD4-immunoglobulin G (rCD4-IgG) were evaluated in a phase 1 study with dose escalation. A total of 16 patients, 6 with AIDS and 10 with AIDS-related complex, were evaluated at two university-affiliated hospital clinics. rCD4-IgG was administered once weekly for 12 weeks to four patients each at doses of 0.03, 0.1, 0.3, and 1.0 mg/kg of body weight. Dosing was intravenous for two patients in the 1.0-mg/kg dose group and intramuscular for the remaining patients. Dosing was intravenous for two patients in the 1.0-mg/kg dose group and intramuscular for the remaining patients. Pharmacokinetic, toxicity, and immunologic variables were monitored with all patients. Administration of rCD4-IgG was well tolerated, with no important clinical or immunologic toxicities noted. No subjects required dose reduction or discontinuation of therapy due to toxicity. No consistent changes were seen in human immunodeficiency virus antigen levels in serum or CD4 lymphocyte populations. The volume of distribution was small, and compared with that of rCD4, the half-life of the hybrid molecule was markedly prolonged following intramuscular or intravenous administration. The rate and extent of absorption following intramuscular dosing were variable. Intramuscular administration of rCD4-IgG appears to be inferior to intravenous dosing from a pharmacokinetic standpoint, with lower peak concentrations and variable absorption. After intravenous administration, peak concentrations of rCD4-IgG in serum (20 to 24 micrograms/ml) that have shown antiviral activity in vitro against more sensitive clinical isolates of human immunodeficiency virus were achieved. The peak concentrations in serum after intramuscular administration were below these levels. Treatment with rCD4-IgG was well tolerated at the doses administered to patients in this study but did not result in significant changes in CD4 lymphocyte counts or p24 antigen levels in serum.

Immigration and rising U.S. fertility: a prospect of unending population growth.

PIP: US fertility fluctuated around 1.8 from 1972-1987, but starting with 1988 it has risen consistently (1.93 in 1988, 2 in 1989, and an estimated 2.1 in 1990). Increasing fertility among immigrants from Asia and Latin America and the rising proportion of high fertility ethnic groups (Asians and Hispanics) contributed most to this rise in fertility. By 2050, the proportion of non-Hispanic whites will fall from 75.6%-54% in the US. If present trends continue, the US population will reach 471 million by 2080. The Hispanic share will rise from 8.7%-23%; Asian share from 3.3%-10%; and Black share from 12.4%-13.6%. Fertility in California, probably the precursor of continual growth in national fertility, climbed 20% between 1982-1988 for a rate of 2.3. In fact, the fertility rate of all ethnic groups rose with fertility among Hispanics growing 10% to 3.5, among Asians 2.5, Blacks 2.4, and Whites 1.7. This can be attributed to California receiving 33% of all immigrants and is home for large minority populations. The proportion of Hispanics and Asians in California increased substantially between 1982-1988 due to immigration. These high fertility populations combined with immigration made up 39% of the increase in fertility in California. If these trends continue, no ethnic majority will exist in California by 2010 and fertility will hit 2.6 by 2020.^ieng

[Immigration, population change, and the American mosaic]. / Immigration, changement demographique et la mosaique americaine.

"This article looks at the relationships among immigration, fertility and mortality to explain the changes that have occurred and will continue to occur in the population of the United States. Emphasis centers on the recent past, the present and the first half of the 21st century. It is pointed out that the nation will undergo major changes in its age and ethnic composition in the near future because of the aging of the baby boom generation and the continued high level of immigration from Latin America and Asia.... In the paper's conclusion, alternative policy options are considered." (SUMMARY IN ENG AND SPA)

How to get there from here: the demographic route to optimal population size.

PIP: Most Americans have a "built-in bias" towards growth. 25 years ago, Americans were concerned with too much growth. Zero population growth was accepted as a goal. The American perception has turned around in the last quarter century. From 1957, with a peak of 3.7, US fertility fell below the level needed to replace the population and reached 1.8 in 1972. Not all growth is good. 3 demographic variables account for all population size changes. In any young population, there is a growth momentum that is "built-in." In talking about the next 60-90 years demographic mathematical models show what would happen under constant conditions. The best known is the stable model. A stable condition comes about if age-specific birth and death rates remain constant over a long period of time. A stable population shows a constant growth rate. "No growth" is described as "stationarity." In 1982, migration was included in the open, stable model. There is a momentum for growth in the US population. It is assumed life expectancy will increase in future years. Fertility and immigration should be balanced. There is not much that can be done about fertility. Much, however, can be done to immigration. A maximum population of 300 million with decline starting before 2080 is practical. Lowering fertility to 1.5 live births per women is possible. Not too many Americans want to entirely end immigration. There are problems with advocating that zero population growth be at current levels, or lower. Some increases will happen because of the build-in growth momentum.^ieng

Immigration to the U.S.: the unfinished story.

PIP: Annual totals of new immigrants and refugees in the US may now be up to the record highs of over a million immigrants counted in 6 years between 1905 and 1914. Since 1979, legal immigrants have averaged 566,000 a year (570,009 in 1985), newly arrived refugees and asylees approved have averaged 135,000, and the "settled" illegal immigrant population is growing by up to 1/2 million a year, according to some estimates. 1/2 of illegal immigrants are persons who entered the US legally but then overstayed the terms of temporary visas. Immigration and Naturalization Service apprehensions of illegal aliens, projected at a record 1.8 million for fiscal year 1986, indicate a sharp increase in illegal border crossers, driven by Mexico's and Central America's mounting population and economic pressures and lured by the prospect of jobs with employers who through a loophole in US immigration law can hire illegal aliens without penalty. The Census Bureau estimates that net immigration now accounts for 28% of US population growth and will account for all growth by the 2030's if fertility stays at the current low 1.8 births per woman. Public opinion strongly favors crubs on illegal immigration and legalization of illegal aliens long resident in the US, and in 1986 Congress enacted legislation to reduce illegal immigration to the US. Asians and Latin Americans now make up over 80% of legal immigrants and Latin Americans comprised 77% of illegal immigrants counted in the 1980 census. Asians far outstrip Latin American immigrants in education, occupational status, and income and might be expected to assimilate in the same manner as earlier immigrant group did. Hispanic immigrants so far appear to favor cultural pluralism, maintaining their own culture and the Spanish language. Research in California indicates that recent Hispanic immigrants (legal and illegal) have helped preserve low-wage industries and agriculture. Illegal immigrants appear to draw more on public health and education services than they pay back in taxes. With or without immigration reform, population and economic pressures in Mexico and the Caribbean Basin ensure that the numbers of people seeking to enter the US are only likely to increase.^ieng

The invisible hand in San Francisco.

PIP: Over 1000 population enthusiasts found their way to San Francisco for the 1986 meetings of the Population Association of America (PAA) April 3-5. 2 pre-meetings included: 1) the Association for Population/Family Planning Libraries and Information Centers-International (APLIC), and 2) the psychosocial workshop. Sexual activity was a major topic of the session on "Fertility: Early and Late." Further investigation of the effects of marriage and fertility on behavior was reviewed in a session entitled "Trends in Household Composition and Living Arrangements." The session "Demography of Crime and Justice" gave the demographic answer to such questions as: Is the crime rate really falling? Opinions in a panel on the future of US international population policy were sharply divided; Agency for International Development representative Alison Rosenberg outlined the re-examination of the Agency's population program that had taken place since the population conference in Mexico City in 1984. The Presidential Address was preceded by the annual awards ceremony. PAA President Paul Demeny focused on an issue that has been at the core of the debate about whether population has good, bad, indifferent, or indeterminate effects on economic development: the extent to which society can entrust the solution of population problems to market forces. This year's PAA meeting echoed growing concern in the population field about low fertility in the more developed world as well as increasing skepticism over the negative consequences of rapid developing country population growth.^ieng

Emigration as an auxiliary method of population control.

PIP: Emigration is an often overlooked auxiliary method of population growth rate reduction that could be useful as a policy variable in low-income countries. Emigration is not a general or permanent solution to overpopulation, but for countries faced with high rates of population growth, it can offer some temporary relief from continual population pressure. In the long run, lowered birth rates will offer the only relief on a world scale. The situation of fertility above replacement and net out-migration may apply to many developing countries. When the argument is expressed in the form of an equation, it demonstrates that the target rate of population growth, if it is lower than the current rate, may be achieved entirely through a reduction in fertility, through out-migration, or through some combination of the 2 approaches involving more or less fertility reduction combined with more or less acceleration of out-migration. A theoretical stable model for a hypothetical country with a population of about 70 million provides an empirical illustration and shows how a diagram of fertility, mortality, and out-migration rates can be used in population policy discussions. It also demonstrates that all combinations of fertility reduction and emigration that lead eventually to a zero rate of population growth do not lead to corresponding stationary populations of identical size.^ieng

Planet earth 1984-2034: a demographic vision.

PIP: In recognition of 1984 as the year of both Orwell's famous futuristic novel and the International Population Conference following up the 1974 World Population Conference, this Bulletin examines the current state of world population and presents the author's speculations on what it might be 50 years from now. World population, now close to 4.8 billion and growing at 1.8%/year, is being shaped by 3 demographic phenomena: prolonged below-replacement fertility in developed nations, perhaps partly in response to the reduced need for workers in the emerging information era; rapid growth despite failing fertility in developing nations, due to earlier rapid mortality decline; and rapid urbanization in developing nations and unprecedented migration from poor to better-off nations. The author's assumptions for nondemographic factors related to population change in the next 50 years are no world war, nuclear or otherwise; global resource adequacy; rapid scientific and technological progress shared equitably; and the demise of capitalism and communism and greatly increased economic aid from advanced to less advanced nations. For 2034 the author envisages nations divided into service/information societies (4% of global population) where immigration balances low fertility to prevent population decline; industrialized nations (38% of total), with fertility close to or at replacement level and growth slowing; developing nations (43%), in sight of replacement level fertility; and least developed nations, with still critical demographic problems but only 15% of the world population. Total population will be 8.03 billion, but growth will be down to 0.8%/year and global zero growth is possible in another 50 years. This relatively optimistic scenario for 2034 will only be possible if mankind acts to see that the stated nondemographic assumptions are borne out.^ieng

Immigration and the stable population model.

This paper reports on work aimed at extending stable population theory to include immigration. its central findings is that, as long as fertility is below replacement, a constant number and age distribution of immigrants (with fixed fertility and mortality schedules) lead to a stationary population. Neither the level of the net reproduction rate nor the size of the annual immigration affects this conclusion; a stationary population eventually emerges. How this stationary population is created is studied, as is the generational distribution of the constant annual stream of births and of the total population. It is also shown that immigrants and their early descendants may have fertility well above replacement (as long as later generations adopt and maintain fertility below replacement), and the outcome will still be a long-run stationary population.

America's baby boom generation: the fateful bulge.

PIP: From 1955-64 nearly 42 million births occurred in the U.S., an unprecedented expansion. The roots of the baby boom lie in the universal rush to early marriage and favorable economic climate for the relatively scarce young men born of the Depression cohort. The impact of the boom interrupted a century-long fertility decline. Pro-marriage, pronatalist norms were revived by the Depression cohort who formed families of at least 2 children or more. During the 1960-70's schools, colleges, and universities were built to accomodate the boom and are now excessive for the baby bust cohort. Unemployment and crime rates rose and fell with the passing of the boom babies through late adolescence and early adulthood. In the 1980's, boom babies will be aged 20-30. Demands for housing will be high. Annual birth numbers will increase even if the rate of childbearing hovers below replacement level at about 1.8 per woman. Per capita earnings and overall labor productivity should improve as the boom baby cohort reaches middle age in the 1990s. However, chances for advancement will be fewer. As the cohort reaches retirement age, the over 65 population will double from 31 million in 2000 to almost 60 million in 2030. Although the burden will be somewhat offset by reduced proportions of under 18-year-olds, the ratio of active workers paying Social Security will fall drastically.^ieng