The durability of previous examinations for cancer: Danish nationwide cohort study

OBJECTIVE

Patients previously examined for cancer with a negative result may present in general practice with ongoing or new symptoms or signs suggestive of cancer. This paper explores the potential existence of a relatively safe period for cancer occurrence after receiving negative examination results for specific types of cancer, including lung (CT thorax), upper gastrointestinal (gastroscopy), colorectal (colonoscopy), bladder (cystoscopy), and breast (clinical mammography).

DESIGN

Register-based time-to-event analyses.

SETTING

Denmark.

SUBJECTS

All 3.3 million citizens aged 30-85 years who on January first, 2017, had not previously been diagnosed with the specific type of cancer were categorized based on the time since their most recent examination.

MAIN OUTCOME MEASURES

Using 1-year follow-up, we calculated the age- and sex-adjusted hazard ratios of being diagnosed with the related cancer, with non-examined individuals as reference. Negative examination results were defined as the absence of a cancer diagnosis within 6 months following the examination.

RESULTS

Previous negative examination results were common, also among those diagnosed with cancer during follow-up. For 10 years after a negative colonoscopy the risk of diagnosing a colorectal cancer was nearly halved. However, already 1 year after a clinical mammography and 2 years after a CT thorax the risk of diagnosing the related cancers was significantly higher among those with a previous negative result compared to non-examined individuals.

CONCLUSION

This study did not identify a post-examination period in which the cancer risk, compared to non-examined individuals, was sufficiently low to confidently rule out any of the investigated cancers.

Response of capsicum (Capsicum annuum L.), sweet corn (Zea mays L.), and tomato (Lycopersicon esculentum Mill.) to inoculation with vesicular-arbuscular mycorrhizae

This greenhouse study investigated the effects of the addition of vesicular-arbuscular mycorrhizal (VAM) inoculum (Glomus mosseae [Nicol. & Gerd.] Gerdemann & Trappe and Glomus etunicatum Becker & Gerdemann) on capsicum (Capsicum annuum L. cv. Target), sweet corn (Zea mays L. cv. Snosweet), and tomato (Lycopersicon esculentum Mill. cv. Floradade) grown in a low P sandy loam (6 mg NaHCO3-extractable P/kg) with 5 rates of P (0, 10.3, 30.9, 92.7, or 278 mg P/kg oven-dry soil; P1, P2, P3, P4, or P5, respectively) and 2 rates of N (50 or 200 mg N/L in irrigation solution; N1 or N2, respectively). The growth periods (from sowing to harvest) for the 3 crops were as follows: 27 August-22 November 1993 for capsicum, 26 August-29 October 1993 for sweet corn, 31 August-22 October 1993 for tomato. For VAM-inoculated capsicum at PI, the dry weight (10.03 g/plant) and mean P concentration in the 5 youngest mature leaves (0.14%) were greater (P < 0.05) than those for uninoculated plants (0.28 g/plant; 0.09% P); a high coefficient of variation necessitated the use of log, transformed data to show differences. At low P rates, dry weight of sweet corn (P1, P2) and tomato (P1) plants colonised with VAM did not differ (P > 0.05) from uncolonised plants, despite inoculated plants having higher P concentrations in index tissues. At intermediate P rates, dry weights of inoculated plants were lower (P < 0.05) than those of uninoculated plants of sweet corn at P3 (81.1 and 102.2 g/plant, respectively) and of tomato at both P2 (11.7 and 34.5 g/plant, respectively) and P3 (39.6 and 52.1 g/plant, respectively). For all 3 crops, a lack of VAM response at high P ( >P4) was related to a lower (P < 0.05) VAM colonisation. The percentage root length colonised by VAM at P5 was only 6.8, 19.6, and 2.4% of that measured at P1 in the case of capsicum, sweet corn, and tomato roots, respectively. Increasing N concentration in the irrigation solution from 50 to 200 mg/L increased (P < 0.05) VAM colonisation of sweet corn (from 28 8 to 36 2%), but had no effect on capsicum and tomato.

Petiole sap nitrate is better than total nitrogen in dried leaf for indicating nitrogen status and yield responsiveness of capsicum in subtropical Australia

This study was conducted to assess the usefulness of petiole sap nitrate and total nitrogen (N) in dried leaf for determining N status and yield response in capsicum (Capsicum annuum L.) grown with plastic mulch and trickle irrigation in subtropical Australia. Five rates of N (0, 70, 140,210, 280 kg/ha) were applied in factorial combination with 2 rates of potassium (K: 0, 200 kg/ha) in randomised block experiments to capsicum cv. Bell Tower grown at Bundaberg Research Station in spring 1990 and autumn 1991. Critical nutrient ranges for nitrate concentration in petiole sap and for total N concentration in dried youngest mature leaf blades plus petioles (YMB + P) were derived at different stages of crop development (bud development, BD; first anthesis, FA; 80% flowering, F; fruit set, FS). Sap nitrate was about 5 times more sensitive to changes in N application than total N. Petiole sap nitrate accounted for a greater amount of the variation in marketable fruit yield (quadratic square root relationships, 0.45 < R2 < 0.83) than total N concentration in dried YMB + P (linear relationships, 0.29 < R2 < 0.74). Simple linear regressions indicated a stronger relationship between applied N and petiole sap nitrate concentration than total N concentration in dried YMB + P (range in R2 values among 8 sampling events: 0.71-0.91 for petiole sap nitrate, 0.35-0.78 for YMB + P total N). For the fertiliser application strategy, 60% of N was applied pre-fruitset and 40% after. Sap nitrate concentrations associated with 95 and 100% of maximum marketable fruit yield increased from BD (5010-6000 mg/L spring, 4980-5280 mg/L autumn) to FA (6220-7065 mg/L spring, 555M000 mg/L autumn). After FA, the range progressively decreased to 1640-2800 and 520-1220 mg/L at FS, for spring and autumn, respectively. It was concluded that petiole sap nitrate was a better indicator of plant N status and yield response than total N concentration in dried YMB + P for capsicum in subtropical Australia. A critical petiole sap K concentration (corresponding with maximum yield and at which no yield response to K addition was measured) of >4800 mg/L was proposed by correlating sap K with yield responses.

Comparison of yield, cob characteristics and sensory quality of six supersweet (sh2) corn cultivars grown in a subtropical environment

Yield and cob characteristics of 6 supersweet corn (Zea mays L.) cultivars, homozygous for the recessive shrunken-2 (sh2) allele, were compared at 3 separate planting dates, in 1987-88, at Bundaberg (lat. 25�S.), Queensland. Sensory quality of the 6 sh2 cultivars and a standard cultivar, homozygous for the recessive sugary (su) allele, were compared in a separate experiment. Marketable yield (total weight of cobs-in-husks with at least 125 mm usable kernels without damage or defects) declined between each of the plantings: midwinter, early spring, late spring. Marketable yield of the cultivar Sucro was consistently high (9.18-13.7 t/ha), whereas, that of Honey Sweet was low (2.88-5.43 t/ha). Total weight of unmarketable cobs (cobs-in-husks with 125 mm usable kernels or cobs-in-husks having at least 125 mm usable kernels, but with damage or defects) was highest for Honey Sweet and ranged between 5.31 and 9.18 t/ha. Marketable yields of the 6 sh2 cultivars were similar to those obtained in other warm climates but were lower than those in cooler climates. The cobs-in-husks of Honey Sweet and Sucro from the midwinter planting were marginally heavier than the preferred cob-in-husk range (310-360 g/cob) demanded on domestic markets; those of Snosweet, Candy Sweet and Florida Staysweet were within the range; and those of Sugar Sweet were significantly (P<0.05) lower. None of the cultivars at the 2 later sowing dates achieved this desirable weight range. Because of the higher yields and larger cobs produced in the midwinter planting, and the higher incidence of disease and heat stress encountered in the later plantings, it is proposed that sh2 cultivar production should be limited to a midwinter sowing in subtropical Bundaberg. Taste panel testing indicated preference for all sh2 cultivars over the standard su cultivar in terms of both general acceptability and texture (P<0.05), and the su cultivar was rated least sweet (P<0.05). Snosweet was rated highest in terms of both general acceptability and texture scores and was also rated the sweetest cultivar.

Maintaining zebu Maure cattle in a tsetse infested area of Mali. II. Epidemiological considerations

Scheduled monitoring of tsetse and other biting flies at Tienfala Forest, Republic of Mali from December 1979 until June 1981 yielded more than 14,500 specimens. Comparisons of the monthly totals of tsetse and other biting flies with the monthly incidence of bovine trypanosomiasis in sentinel cattle suggested that biological transmission by a single riverine species of tsetse, Glossina palpalis gambiensis, accounted for most if not all disease transmission at the study site. The data obtained also suggested that human decisions had contributed to the magnitude if not the degree of the disease problem at the study site and that viable solutions to the disease problem exist.