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PubMed2005

[Triatoma rubrovaria (Blanchard 1843): life table of nymphs, duration of the forms and posture of the females].

The authors followed the development of 150 eggs of Triatoma rubrovaria to enable the construction of a life table for the nymphs. The winged form was reached by 94.64% of the individuals, of which 79 were males and 65 females. The mean lifetime of the males was 115 days and 99 days for the females. Part of this group was divided into 30 couples and kept separated to facilitate the count of egg laying by each female. Another lot was also formed of 30 males and 30 females but these were housed together in a glass crystallizer that allowed the observation of a larger number of eggs laid (7,832 eggs) in relationship to that of the females with only one male (total 5,167 eggs). The good development of the individuals and reproduction of the species in the experimental conditions demonstrated the capacity to maintain colonies of Triatoma rubrovaria in laboratory conditions.

Animals↗
PubMed1987

Studies on autogeny in Culex tarsalis: 3. Life table attributes of autogenous and anautogenous strains under laboratory conditions.

The reproductive biology and life table attributes of autogenous and anautogenous strains of Cx. tarsalis which were selected from the same parent colony were compared under laboratory conditions. Autogenous mosquitoes required 1 day longer to complete immature development, but oviposited 1 to 2 days earlier than anautogenous mosquitoes. Autogenous females readily imbibed blood meals from restrained chickens if ovarian maturation had not progressed to Christophers' Stage III. Wing length and life expectancy were not significantly different between strains; however, autogenous females laid a significantly smaller number of eggs per raft during initial oviposition than anautogenous females. Egg raft size did not differ significantly between strains during subsequent ovipositions resulting in similar net reproductive rates (Ro). Earlier oviposition and a comparable Ro resulted in a greater intrinsic rate of increase (rm) and birth rate (b) for autogenous than anautogenous cohorts. Thus, highly autogenous populations would be able to exploit newly created surface water breeding sources more rapidly than highly anautogenous populations. However, highly autogenous populations probably would not be able to transmit a horizontally maintained arbovirus as efficiently as anautogenous populations, since autogenous females imbibe their initial blood meal later in life than anautogenous females.

Actuarial Analysis↗
PubMed1993

Proresid therapy in rheumatoid arthritis. A comparison with injectable gold using life-table analysis.

Proresid, mainly consisting of podophyllotoxin derivatives and two glycosides thereof, has been used as a disease-modifying antirheumatic drug in Sweden since the late 1960s. A life-table analysis of Proresid treatment averaging 41 months (range 4-144) in 79 rheumatoid arthritis patients showed a termination rate of 40, 56, 75 and 85% after 1/2, 1, 2 and 4 years, respectively. Dominant reasons for discontinuing therapy were inefficacy (37%) and gastrointestinal symptoms (35%). The risk of discontinuation of therapy due to inefficacy was constant over time, while the risk due to other causes, including side effects, gradually decreased. A comparison with injectable gold therapy showed, after adjusting for confounding factors, that the total termination incidence was higher (p < 0.05) in the Proresid-treated patients. A comparison with the regional cancer register of 334 patients exposed to Proresid for a mean time of 2.2 years showed no increased cancer risk after a mean observation time of 6.1 years.

Adolescent↗
PubMed2004

A 7-year life table analysis from a prospective study on ITI implants with special emphasis on the use of short implants. Results from a private practice.

This paper reports on a 7-year life table analysis on ITI titanium plasma-sprayed (TPS) and sandblasted and etched (SLA) implants placed in a private practice and loaded for at least 1 year. In 236 patients, 528 (264 TPS and 264 SLA) implants were placed, 351 (66.5%) implants rehabilitated the posterior region and 71.1% implants were < or =11 mm. In the posterior mandible and maxilla, the mean implant length was 9.90 and 9.74 mm respectively. Implant length was determined through standard radiographs only. Increase of the number of implants or reduction of the width or length of the rehabilitations was no specifically sought for the shorter implants. One hundred and twenty-two SLA implants were loaded within 63 days. All early loaded SLA implants resisted the applied 35 N cm without rotation or pain. Three implants failed, one early and two late failures, all were SLA implants placed in the mandible. Shorter implants did not fail more than longer ones. The cumulative success rate was 99.40%. The predictable use of short implants supporting single crowns and small fixed partial dentures of 2-4 units supported by two to three implants permitted (1) restricting the need for sophisticated and expensive presurgical procedures aimed to determine precisely the available bone height by computerized radiographic methods, (2) the placement of prosthetically driven restoration instead os surgically driven ones, (3) reducing the indications span for complex invasive procedures like sinus lift and bon grafting procedures, (4) facilitating the surgery, without attempting to place the longest implant and (5) avoiding the occurrence of sensation disturbance. The safe use of short implants in a private practice should make implant therapy simpler and accessible to a higher number of patients and practitioners.

Adolescent↗
PubMed1992

Age at onset and life table risks in genetic counselling for Huntington's disease.

Age related genetic risk data for carrying the gene for Huntington's disease in relatives at risk, based on a previously documented life table approach, are presented in a form allowing ready access for use in genetic counselling. Figures are given for first degree relatives and for second degree relatives showing varying age combinations of consultand and intervening parent at risk. Data are also given for the risk of developing Huntington's disease over varying finite periods in relation to age. The availability of this information in tabular form should help those involved in genetic counselling for this disorder in providing accurate risk estimates to relatives; the data are also of importance for combination with genotype information in predictive testing.

Adult↗
PubMed1984

The uses and abuses of life-table methods in vascular surgery.

This paper details the calculations involved in a life-table analysis and appraises the current use of this technique in vascular research. We suggest that the presentation of patency curves should be standardized and recommend that: curves are presented as step rather than continuous graphs; the number of patients remaining in a study are shown at intervals along patency curves; the length of time for which a curve is claimed to hold is more rigorously defined; an attempt is made to increase, where possible, the frequency of patient review, particularly in the immediate postoperative period; ways of increasing the total sample size (e.g. multicentre studies) are investigated. We also recommend that a set of definitive guidelines on the presentation of graft patency data acceptable to all the major vascular journals be sought.

Actuarial Analysis↗
PubMed1993

Age of marriage and length of the first birth interval in a traditional Indian society: life table and hazards model analysis.

The length of the first birth interval is one of the strongest and most persistent factors affecting fertility in noncontracepting populations, with longer intervals usually associated with lower fertility. Compared to Western society, the average length of the first birth interval is much longer in traditional Indian society. Yet Indian fertility rates are higher because of either ineffective family planning procedures or deliberate nonuse of birth control and because of the high proportion of the population that is married. Here, we examine the effects of various sociodemographic covariates (with an emphasis on the role of age at marriage) on the length of the first birth interval for two states of India: Assam and Uttar Pradesh. Life table and multivariate hazards modeling techniques are applied to the data. Covariates such as age at marriage, present age of mother, female's occupation, family income, and place of residence have strong effects on the variation of the length of the first birth interval. For each subgroup of females (classified according to different levels of the covariates), the median length of the first birth interval for the Assam (Bengali-speaking) sample is shorter than that of the Uttar Pradesh (Hindi-speaking) sample.

Adolescent↗
PubMed1993

Methotrexate therapy in rheumatoid arthritis: a life table review of 587 patients treated in community practice.

To determine whether methotrexate (MTX) maintains its effectiveness in rheumatoid arthritis (RA) in the setting of community based private rheumatology practice we used life table analysis to review the combined experience of a group of these practices. Of 587 patients with RA who started to take MTX, total termination rate at 70 months was 24.4% with most terminations prompted by drug toxicity. Older age (greater than 65 years) was associated with higher rates of toxicity. Treatment termination rates varied substantially between rheumatologists. We conclude that MTX therapy for RA is well tolerated and maintains effectiveness for at least 70 months.

Adult↗
PubMed1993

Long-term intraocular pressure control by trabeculectomy: a ten-year life table.

A retrospective study of 179 eyes in 127 patients who underwent trabeculectomy at Sydney Eye Hospital under the supervision of two surgeons between 1977 and 1982 was carried out. Survival analysis by life table method shows cumulative two, five, and 10 year success rates to be 78%, 70%, and 67% respectively, with mean duration of intraocular pressure control (IOP < 21 mmHg) being 88 months. Antiglaucoma medication improved the long-term survival significantly (Hazard Ratio of 0.49 and P = 0.01) so that when the definition for failure is taken as IOP > 20 mmHg while using medication, the two, five and 10 year success rates were 89%, 87% and 86% respectively. A rise in average intraocular pressure is seen between two weeks and three months after trabeculectomy. The improvement in long-term success rate with use of topical steroids was suggestive (Hazard Ratio of 0.69) but not conclusive (P = 0.21). No difference was found in survival comparing fornix versus limbal based flap technique.

Adolescent↗
PubMed1992

Life table analysis of infant mortality and feto-infant mortality distributed on causes of death in Denmark 1983-1987.

The survival function of 263,322 singletons of the 1983-1987 Danish birth cohorts (262,159 liveborn and 1163 stillborn babies) with mortality distributed on functional groups of underlying causes of death is presented in two graphic forms on the basis of Kaplan-Meier estimates. About half of all first-day deaths in liveborn babies occurred during the first 4 hours. More than half of all first-week deaths happened during the first day. More than half of all deaths from 31 weeks to 76 weeks after the first day of the last menstrual period (LMP) were either fetal deaths prior to the onset of labour unexplained by fetal factors or unexplained sudden infant death syndrome (SIDS) deaths. Graphic presentation of feto-infant mortality distributed on functional cause-of-death groups improved the expression of the relative contribution and timing of the different causes of deaths. Despite a high autopsy rate and a uniform coding practice the distribution on causes of deaths from register data should be interpreted with caution. Full use of the feto-infant approach is only achieved with data which include late abortions. Thus the feto-infant approach is of special interest in countries which have registers of live births and fetal deaths from week 22 of gestation or earlier. The integration of the life table approach and analysis of underlying causes of deaths should be further explored as a way of utilizing vital statistic databases for the evaluation of perinatal care.

Cause of Death↗
PubMed1981

Occupational life tables for cerebrovascular disease and ischemic heart disease in Japan compared with England and Wales.

Life tables have been calculated for cerebrovascular disease and ischemic heart disease in various occupational groups in Japan, and England and Wales. For cerebrovascular disease there are large occupational differences in both countries, and the experience of the lowest-ranking Japanese group (administrators and managers) is better than that of the highest-ranking group in England and Wales (miners). For ischemic heart disease the occupational variations within each country are less, and all Japanese groups fare better than any groups in England and Wales. Within each country mortality from cerebrovascular disease in different occupations has many positive and significant correlation coefficients with rates for stillbirth, and mortality from infections, cancers, etc. However, mortality from ischemic heart disease shows relatively less correlation coefficients with other diseases.

Actuarial Analysis↗
PubMed2001

Life table parameters, reproductive rate, intrinsic rate of increase, and estimated cost of rearing Podisus maculiventris (Heteroptera: Pentatomidae) on an artificial diet.

The impact of an insect-free artificial diet provided at nymphal and/or adult stage upon the developmental rate, life table parameters, and fertility table parameters was examined for Podisus maculiventris (Say). This study showed that when fed an insect-free artificial diet during both the nymphal and adult stage, developmental time was prolonged, preoviposition period was extended, and reproductive rate (R0) and intrinsic rate of increase (r) were significantly lower than when fed larval insect prey at both nymphal and adult stages. Additionally, feeding larval prey to adults reared as nymphs on an artificial diet significantly increased the proportion of fertile females, the number of eggs laid by mated females, the reproductive rate and intrinsic rate of increase, but the mean generation time was not significantly different. Likewise, feeding artificial diet to adults reared on larval prey resulted in a significant reduction in reproductive rate and intrinsic rate of increase. The "realized" cost to rear P. maculiventris on the artificial diet was calculated (as the cost to double the population size) using raw material cost, fertility table parameters and doubling time values. Raw material cost for rearing P. maculiventris colony on Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae) was only 1.4 times higher than the cost of artificial diet raw materials required to rear the same size colony. However, the realized cost of rearing was 3.5 times higher when rearing on artificial diet because of the prolonged developmental time and reduced reproductive output. The cost efficiency of rearing a beneficial insect on an artificial diet that decreases the intrinsic rate of increase of a colony is discussed, as well as the advantages and disadvantages of supplementing adult diets with natural prey at the reproductive stage.

Animal Husbandry↗
PubMed2003

Measuring the impact of hepatitis A virus in Chinese cities: a life table approach.

The infection of hepatitis A virus is an important public health problem in China. In 1990, a survey on seroprevalence of anti-hepatitis A was conducted in eight large cities of population size between one to four million. The results were used to analyze the impact of hepatitis A. In our study, we used life table techniques to determine the impact that the hepatitis A virus (HAV) has on these eight cities by computing the expected years of life with anti-hepatitis A virus. We compared the results from our approach with those from a previous method. The expected years of life with anti-hepatitis A virus were 53.82, 54.65, 44.26, 53.89, 46.18, 55.77, 55.31 and 49.89 for the eight cities (Xi'an, Huhehaote, Chongqing, Nanjing, Jinan, Ha'erbin, Fuzhou and Nanchang), respectively. The hepatitis A virus had the greatest impact in Ha'erbin in northeastern China; whereas, the impact was lowest in Chongqing in southwestern China. However, based on the previous indicator, Chongqing was ranked the highest among these cities. Through our comparative study of the methods, our approach provides a better measure on the burden of the disease than the previous method. It also identifies subgroups of the population where the disease has its greatest impact on the population.

China↗
PubMed1992

Life table analysis of 879 treatment episodes with slow acting antirheumatic drugs in community rheumatology practice.

In 596 patients with RA managed over a decade in a community practice setting, 879 slow acting antirheumatic drug (SAARD) treatment episodes were analyzed using 5-year life tables. The probability of continuation of therapy was 50% by 9-24 months for all drugs except for methotrexate (MTX), which was 62% by 5 years [corrected]. MTX treatments were of significantly longer duration than those of all other SAARD (p less than 0.001); terminations for both inefficacy (p less than 0.001) and toxicity (NS) were less likely. These findings concur with recent evidence suggesting that MTX is a superior SAARD in this setting.

Adult↗
PubMed1990

Competing risk analysis of life table data: application to lifetime risk computation.

In this pedagogic note we propose to assess the safety of treatment in a clinical trial, or the effect of risk exposure in a chronic animal study, in terms of two lifetime risks. These risks are computable from life table type data and take into account the effects of competing risks. We first describe their computational procedures in detail to demonstrate the need for their implementation in a computer program. We then illustrate their practical application through use of the data obtained from an actual clinical study.

Health Status Indicators↗
PubMed1991

Conservative laparoscopic excision of endometriosis by sharp dissection: life table analysis of reoperation and persistent or recurrent disease.

OBJECTIVE: To determine the long-term outcome after laparoscopic excision of endometriosis. DESIGN: This longitudinal unmatched study evaluated surgical outcome using follow-up questionnaires and evaluation of reoperations with results presented in life table format. SETTING: Surgery was performed by a private practitioner at a referral center. PATIENTS: All 359 patients undergoing laparoscopic excision of endometriosis between December 12, 1980, and March 31, 1990, were studied. INTERVENTIONS: Endometriosis, including deeply invasive disease, was completely excised laparoscopically using 3-mm scissors and graspers. Adjunctive medical therapy was not used. MAIN OUTCOME MEASURES: Extent of disease present at reoperation and quarterly rates of reoperation and recurrent/persistent disease are used as indicators of efficacy of surgery. RESULTS: Interval rates of reoperation and recurrence/persistence of disease and extent or invasiveness of disease when found at reoperation did not increase with the passage of time after surgery. The maximum cumulative rate of recurrent or persistent disease was 19%, achieved in the 5th postoperative year. CONCLUSION: Laparoscopic excision of endometriosis results in a low rate of minimal persistent/recurrent disease. The natural history of endometriosis after surgery suggests a rather static nature of the disease.

Endometriosis↗