Biomedical subjects
Publications and source records attributed to R D Lee.
"In a recent paper, Lee and Carter developed a new method for analyzing and forecasting time series of age specific mortality, and applied it to the U.S. population. In this paper, we extend that method to deal with various problems of incomplete data common in Third World populations, and then apply the method to forecast mortality in Chile." (SUMMARY IN ENG)
Change in marital fertility in 407 Prussian Kreise from 1875 to 1910 is modeled to depend on the gap between the number of desired surviving births, N*, divided by child survival, s, and the number that would be born under natural marital fertility, M, given the age at marriage. Some fraction of this gap is averted, depending on the propensity to avert unwanted births, D. Although none of these components is observed directly, we can estimate each indirectly under strong assumptions. Decline in N*/s accounts for twice as much of the decline in fertility as does an increase in D. Natural fertility rose during the period. Unwanted births increased slightly, despite a tripling of births averted. The most important causes of decline in N* were increases in female labor supply, real income, and health workers. A rising level of education is the most important cause of increasing propensity to avert births. Demand-side changes were important causes of the transition, but changes in readiness to contracept also were important, as was the interaction of the two.
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Visual laser ablation of the prostate was performed on 108 patients (ages 44 to 84 years) as an outpatient procedure from May 1992 to October 1992. Preoperatively, the patients underwent digital rectal examinations, determination of prostate specific antigen levels and transrectal ultrasound guided biopsies when necessary to rule out the presence of prostate cancer. The Urolase laser fiber delivery system was used to transmit laser energy from a neodymium: YAG generator. For the 97 patients with preoperative and postoperative American Urological Association symptom index testing, scores decreased by an average of 12.59 (p < 0.001). For the 75 patients with preoperative and postoperative uroflow rates an average increase of 4.92 ml. per second (p < 0.001) was noted following the procedure. Only 3 patients required hospitalization for an average of 1.33 days. No patient required a blood transfusion. There have been no fluid or electrolyte abnormalities following visual laser ablation of the prostate. There have been no recognizable urethral strictures, deaths or postoperative sepsis. Only 3 patients experienced retrograde ejaculation. We found visual laser ablation of the prostate to be a cost-effective and less morbid alternative to traditional transurethral resection of the prostate.
"This paper describes a particular approach to stochastic population forecasting, which is implemented for the U.S.A. through 2065. Statistical time series methods are combined with demographic models to produce plausible long run forecasts of vital rates, with probability distributions. The resulting mortality forecasts imply gains in future life expectancy that are roughly twice as large as those forecast by the Office of the Social Security Actuary.... Resulting stochastic forecasts of the elderly population, elderly dependency ratios, and payroll tax rates for health, education and pensions are presented."
"This paper examines differentials in observed and forecasted sex-specific life expectancies and longevity in the United States from 1900 to 2065. Mortality models are developed and used to generate long-run forecasts, with confidence intervals that extend recent work by Lee and Carter (1992). These results are compared for forecast accuracy with univariate naive forecasts of life expectancies and those prepared by the Actuary of the Social Security Administration."
We compared the general operating features and nutrient databases of six microcomputer dietary analysis systems. A 3-day food record with 73 food items was entered into each program; nutrient averages were compared with the US Department of Agriculture Nutrient Data Base for Standard Reference (USDA NDB), full version, release 9, for microcomputers. The six programs were found to vary widely in cost, number of foods and nutrients in the database, use of non-USDA data and imputation of data for missing values, number of print/export options, time to analyze the 3-day food record, and overall ease of use. Although all of the microcomputer dietary analysis systems were within 7% of the USDA NDB for energy, protein, total fat, and total carbohydrates, the proportion of other nutrients varying more than 15% from the USDA NDB varied considerably between programs. Variance among programs for 3-day food record nutrient values occurred because of differences in the number of food items included in the database (leading to varying degrees of substitution), the recency of the nutrient data (whether or not the most recent USDA releases had been incorporated), and the number of missing values (the degree to which non-USDA sources or estimated calculations were used to fill in the blanks from the USDA standard). Our results demonstrate that it is important for each dietitian to carefully choose a microcomputer dietary analysis system that is suitable to specific and predetermined needs.
We describe 3 patients with ureteral calculi who failed multiple extracorporeal shock wave lithotripsy treatments and whose stones could not be visualized by ureteroscopy despite radiological confirmation. We contend that these ureteral stones migrated submucosally and are refractory to the aforementioned treatment modalities. Each patient had a common presenting complaint of intermittent flank pain 5 years in duration, leading us to believe that long-standing stone impaction is a prerequisite for this entity. Our experience is reviewed.
Two diene metabolites of valproic acid (VPA), (E)-2-n-propyl-2,4-pentadienoic acid and (E)-2-(1'-propenyl)-(E)-2-pentenoic acid, were stereoselectively synthesized. Mesylate elimination in the final step to produce the unsaturation at position 2 was stereospecific for the (E)-configuration in the case of 2. Gas chromatography-mass spectroscopy and NMR were used to confirm the configuration of each diene including the minor isomers, (Z)-2-n-propyl-2,4-pentadienoic acid and (Z)-2-(1'-propenyl)-(E)-2-pentenoic acid. Analysis of the dienes, as PFB derivatives by negative chemical ionization GC-MS from a serum extract of a patient on VPA therapy, revealed the presence of four peaks that in order of elution correspond to 9, 18, 1, and 2.
Lee's (1974) formal demographic feedback models summarize the implications for births and age-structure of neo-Malthusian theories of baby booms such as those of Easterlin. For some parameter values, such models imply sustained cycles, so-called "limit cycles", in births. Frauenthal and Swick recently reestimated a continuous-age version of Lee's basic cohort model with U.S. series and, contrary to Lee's original findings, concluded that "limit cycles oscillations have been occurring in U.S. births." This article disputes their conclusion, ascribing it to an inconsistency in detrending procedures. Furthermore, it corrects Lee's original conclusion by showing that his alternative period labor-force feedback model, estimated from U.S. series, leads to cycles of implausibly long period. This article thus reopens the question of whether any feedback model could account for the observed cycles in U.S. births.
"A simple model of Malthusian population growth combined with population-induced technological progress generates accelerating growth. The model may be relevant for a first stage of growth in which natural resource limitations can be overcome through technological progress; it is not applicable to a later stage in which resource constraints are more resistant. Parameter values are roughly inferred from historical experience." (SUMMARY IN FRE)
Human population dynamics, at least until the past century, have probably been governed by homeostasis and in this resembled those of other animals. Because human population homeostasis was probably substantially weaker than among large mammals, its operation has been less obvious. Nonetheless, the empirical evidence for advanced agriculturalists is compelling. Unlike animals, the human population has tended toward equilibria that have been tending upward at an accelerating rate. The acceleration might reflect long-run positive feedback between density and technological progress, as Boserup has suggested. Because homeostasis was weak, its role in shorter run historical explantation is limited; its force was gentle and easily overwhelmed by other particular influences. Malthusian oscillation, in the sense of distinctive medium-run dynamics arising from homeostasis, probably did not occur. And because homeostasis was weak, density dependence can in principle explain only a minute proportion of the annual variation in population growth rates. Yet homeostasis plays an essential role in demographic theory. Without it, we are incapable of explaining population size and change over time except by recounting a mindless chronology of events back to the beginning of humanity--whenever that was. Without it, we cannot explain the response of population growth to economic growth. Without it, we cannot explain recovery from catastrophe or the rapid natural increase in many frontier regions. Without it, we cannot properly analyze the influence of climatic variation and other partially density-independent factors. Our basic understanding of human history requires a grasp of what homeostasis can explain and what it cannot. A homeostatic approach to population dynamics also leads to questions about the roles of reproductive norms and institutions, not just whether they encourage high or low fertility, but whether they make natural increase responsive to resource abundance. And if they do, whether they strike the balance of population and the means of subsistence at a relatively prosperous or impoverished level. Such considerations may contribute to an understanding of broad preindustrial differences among the regions of the world in densities, average levels of vital rates, and living standards--which was very much how Malthus viewed the matter. Ordinary homeostatic tendencies essentially vanish in the course of economic development, and they were probably all but gone from much of Europe by the end of the 19th century.(ABSTRACT TRUNCATED AT 400 WORDS)
A case of scrotal fat necrosis is presented. The clinical presentation usually is characteristic and the condition can be managed nonoperatively.
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Necrobiotic xanthogranuloma with paraproteinemia is characterized by multiple nodules or plaques that involve the periorbital area along with other parts of the body. A dysproteinemia due to an IgG paraprotein is associated with the condition; low serum complement, cryoglobulinemia, leukopenia, and hyperlipemia are also sometimes seen. Multiple myeloma is present in some cases. Two cases of necrobiotic xanthogranuloma with IgG monoclonal gammopathy were seen. Both initially had ocular symptoms and in the second case, the ocular manifestations have dominated the clinical picture. Histologically, these granulomas are characterized by collagen necrobiosis and by the presence of many foamy histiocytes and Touton giant cells. Because necrobiotic xanthogranuloma with monoclonal gammopathy frequently has prominent manifestations in the orbital region, may result in dysfunction of the eyelids or extraocular muscles, and is associated with potentially life-threatening systemic conditions, its recognition by the ophthalmologist is important.
Dermatology has entered a new dimension with the introduction of the laser. There are expanding clinical indications for laser excision. The CO2 laser in the cutting mode can incise tissue as sharply as finely honed steel, yet its photocoagulative properties allow rapid sealing of blood vessels and lymphatics. The physician can thereby perform in a relatively bloodless surgical field. Minimal adjacent normal tissue is injured, there is less local postoperative edema, and fewer postoperative analgesics are required. Since there is no need to use epinephrine as a local vasoconstrictive agent and there is no need to use electrocoagulation for control of hemorrhage, CO2 laser excision presents less risk to the medically compromised patient. The CO2 laser may also diminish the risk of seeding or spreading neoplastic cells in the perioperative field.
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This paper develops a stock adjustment model relating total expected births to conventional aggregate fertility rated for married women over 25. Each year, cohorts bear about 20 percent of their additional expected births. Aggregate U.S. rates have been consistent with expectations as expressed in surveys between 1955 and 1975; indeed, total expected births may be inferred from aggregate fertility behavior. A peculiar empirical finding is that the additional expected fertility of nonterminators has not changed since 1955, despite the dramatic decline in total expected and actual fertility. The model leads to a dynamic expression for the duration pattern of current and cumulative fertility and for the proportion of couples who have terminated childbearing. The model is also used to analyze the effects of changing contraceptive failure rates on fertility patterns. For example, a decline in "timing" failure rates increases duration-specific fertility five years later.