Foot Infections in Swimming Baths

A 10% random sample of all bathers at a public swimming bath were examined for tinea pedis and verruca.The overall incidence of tinea pedis was 8·5% and of verruca 4·8%. The incidence of tinea pedis in 205 male adults was 21·5%, in 288 boys 6·3%, in 60 adult females 3·3%, and in 220 girls 0·9%. The incidence of verruca in juveniles ranged from 4·2% in boys to 10·5% in girls.It was clear that both infections spread within the baths, and since a relatively small proportion of users admitted to taking precautions to avoid contracting or developing infections it seems advisable that more publicity about recommendations on foot care should be provided.     

Meta-Analysis of Randomised Clinical Trials Comparing Idarubicin + Cytarabine with Daunorubicin + Cytarabine as the Induction Chemotherapy in Patients with Newly Diagnosed Acute Myeloid Leukaemia

Background

To determine whether the use of idarubicin+cytarabine (IA) is more effective than the use of daunorubicin+cytarabine (DA) as induction chemotherapy for patients with newly diagnosed acute myeloid leukaemia.

Methods

A computer-based search was performed. Randomised trials comparing IA with DA as induction therapy for newly diagnosed AML were included in this meta-analysis. The primary outcome of interest for our analysis was survival (disease-free survival, event-free survival and overall survival); the secondary endpoint was complete remission.

Results

Ten trials with 4,060 patients were eligible for this meta-analysis. Our pooled results suggest that IA is associated with a significant advantage in CR (RR = 1·23; 95% CI = 1·07–1·41, p = 0.004), EFS (HR = 0·64; 95% CI = 0·45–0·91, p = 0.013), and OS (HR = 0·88; 95% CI = 0·81–0·95, p = 0.02) but not in DFS (HR = 0·90; 95% CI = 0·80–1·00, p = 0.06). In the subgroup analysis, age had a significant interaction with OS and CR benefits.

Conclusion

Our analysis indicated that IA could improve the duration of overall survival compared to DA as induction therapy for young patients with newly diagnosed AML. Further study is needed to determine whether IA can produce clinical benefits in selected genetic or molecular subgroups of young AML patients.     

Intraepithelial Carcinoma of the Cervix Uteri in Women Aged under 35 Years

The number of cases of intraepithelial carcinoma of the cervix among women of different age groups has been related to the number of cervical smears from women of the same age groups. Among women aged 25 to 34 years the incidence of intraepithelial carcinoma was 0·67% and among those aged 35 to 44 years it was 0·75%. The overall rate of intraepithelial carcinoma in women under 35 years was 0·55% compared with an overall rate of 0·59% in women over 35 years.If screening of women for cervical cancer is to play any part in preventive medicine it is suggested that the national campaign for the early detection of cervical cancer should be expanded to encourage practitioners to take cervical smears from younger women, particularly from those under 35 years.     

Clinical Problems: Hepatitis in Dialysis Units in the United Kingdom

A prospective study of hepatitis in 20 dialysis units in the United Kingdom showed that the number of units with outbreaks increased from one in 1968 to three in 1969 and the overall attack rate rose from 1·7 to 5·3% in patients and from 0·5 to 1·3% in staff.In July 1969 a pilot study of patients'' sera showed that all of the outbreaks were associated with Australia (Au) antigen. Au antigen was not detected in the unaffected units or in one unit in which there were several patients with abnormal liver function.In January 1970 systematic prospective testing for Au antigen was begun. Au antigen was detected in single patients in five more of the 20 units. The transfer of the affected patients to isolation for dialysis seemed to prevent the spread of infection in the units. The incidence of hepatitis in 1970 was 5·6% in patients and 0·4% in staff.     

Septic Gonococcal Dermatitis

The overall incidence in gonorrhoea of septic gonococcal dermatitis was found to be 1·9% (3% for the females and 0·7% for the males). In 23 patients the common presenting symptoms were arthritis or arthralgia and bouts of fever, but the characteristic skin lesions served as an early clue to the diagnosis, and Neisseria gonorrhoeae was isolated from the genitourinary tract or from the blood. With the use of immunofluorescent techniques gonococci were also found in smears prepared from the skin lesions. An immune response to gonococci was found with the complement fixation technique in 90% of the patients. The response to treatment with penicillin was prompt, with complete relief from joint pains and fever, usually within two to seven days. The skin lesions faded within a few days, but scars could be observed for up to four weeks.     

Detection of Streptococcus pneumoniae and Haemophilus influenzae Type B by Real-Time PCR from Dried Blood Spot Samples among Children with Pneumonia: A Useful Approach for Developing Countries

Background

Dried blood spot (DBS) is a reliable blood collection method for storing samples at room temperature and easily transporting them. We have previously validated a Real-Time PCR for detection of Streptococcus pneumoniae in DBS. The objective of this study was to apply this methodology for the diagnosis of S. pneumoniae and Haemophilus influenzae b (Hib) in DBS samples of children with pneumonia admitted to two hospitals in Mozambique and Morocco.

Methods

Ply and wzg genes of S. pneumoniae and bexA gene of Hib, were used as targets of Real-Time PCR. 329 DBS samples of children hospitalized with clinical diagnosis of pneumonia were tested.

Results

Real-Time PCR in DBS allowed for a significant increase in microbiological diagnosis of S. pneumoniae and Hib. When performing blood bacterial culture, only ten isolates of S. pneumoniae and none of Hib were detected (3·0% positivity rate, IC95% 1·4-5·5%). Real-Time PCR from DBS samples increased the detection yield by 4x fold, as 30 S. pneumoniae and 11 Hib cases were detected (12·4% positivity rate, IC95% 9·0-16·5%; P<0·001).

Conclusion

Real-Time PCR applied in DBS may be a valuable tool for improving diagnosis and surveillance of pneumonia caused by S. pneumoniae or Hib in developing countries.     

Results of Surgery for Inflammatory Bowel Disease: A Further Survey of One Hospital Region

Case records have been studied for the results of surgery in 294 patients operated on for inflammatory bowel disease during 1967-72 at 34 non-teaching hospitals within the North-east Metropolitan Hospital Region. All patients treated surgically for acute colitis and those treated for chronic disease by total colectomy were included.The postoperative mortality of the primary surgery was 23·7%. The mortality was 2·1% in patients treated by elective operation, 37·6% in patients coming to urgent operation, and 60·9% in patients treated by emergency operation. The three most important factors affecting the mortality were considered to be: increasing age of the patient, the presence of established colonic dilatation, and preoperative perforation of the colon.     

Interaction of Fusarium oxysporum f. sp. ciceri and Meloidogyne javanica on Cicer arietinum

Interaction of Meloidogyne javanica and Fusarium oxysporum f. sp. ciceri was studied on Fusarium wilt-susceptible (JG 62 and K 850) and resistant (JG 74 and Avrodhi) chickpea cultivars. In greenhouse experiments, inoculation of M. javanica juveniles prior to F. oxysporum f. sp. ciceri caused greater wilt incidence in susceptible cultivars and induced vascular discoloration in roots of resistant cultivars. Nematode reproduction was greatest (P = 0.05) at 25 °C. Number of galls and percentage of root area galled increased when the temperature was increased from 15 °C to 25 °C. Wilt incidence was greater at 20 °C than at 25 °C. Chlorosis of leaves and vascular discoloration of plants did not occur at 15 °C. The nematode enhanced the wilt incidence in wilt-susceptible cultivars only at 25 °C. Interaction between the two pathogens on shoot and root weights was significant only at 20 °C, and F. o. ciceri suppressed the nematode density at this temperature. Wilt incidence was greater in clayey (48% clay) than in loamy sand (85% sand) soils. The nematode caused greater plant damage on loamy sand than on clayey soil. Fusarium wilt resistance in Avrodhi and JG 74 was stable in the presence of M. javanica across temperatures and soil types.     

General Practice Observed: The Distress of Dying

A simple method of recording the distress of dying patients is described. Significant differences occurred between deaths at home and in hospital for three factors. Patients dying at home were (a) more likely to be fully alert shortly before death (P < 0·05); (b) less likely to be suffering from vomiting, incontinence, or bedsores (P < 0·001); and (c) less likely to have unrelieved physical distress (P < 0·05). No significant differences occurred in the distress of patients dying in general-practitioner compared with other hospitals, though the numbers compared were small and a larger study might prove useful.     

Impaired renal functional reserve and albuminuria in essential hypertension

The stimulatory effects of an infusion of amino acids on glomerular filtration rate has previously been used to measure renal functional reserve and detect glomerular hyperfiltration. Thirty four patients with mild to moderate essential hypertension and seemingly normal renal function and 22 healthy controls were given infusions of amino acids to investigate whether renal functional reserve is reduced in essential hypertension and to detect patients at risk of renal damage. Although basal creatinine clearance increased after the infusion of amino acids in the controls (mean 27·9 ml/min; 95% confidence interval 18·2 to 37·6), the overall change was lower in the patients (mean 13·4 ml/min; 8·3 to 18·5), 11 of the 34 showing no increase at all. In these 11 non-responders the mean systolic blood pressure was higher than that in the 23 others (178·5 mm Hg v 157 mm Hg, respectively). Mean urinary albumin excretion was abnormal in the patients (93·3 mg/24 h; 44·2 to 142·4); eight of the 11 non-responders had an albumin excretion above the normal range (>20 mg/24 h). In the 11 patients without renal functional reserve a positive correlation was found between basal creatinine clearance and albumin excretion (r=0·695).As consumed renal reserve and albuminuria are markers of glomerular hyperfiltration studying renal function before and after infusion of amino acids can detect hypertensive patients at risk of progressive renal damage.     

Risk Factors for Death among Children Less than 5 Years Old Hospitalized with Diarrhea in Rural Western Kenya, 2005–2007: A Cohort Study

Background

Diarrhea is a leading cause of childhood morbidity and mortality in sub-Saharan Africa. Data on risk factors for mortality are limited. We conducted hospital-based surveillance to characterize the etiology of diarrhea and identify risk factors for death among children hospitalized with diarrhea in rural western Kenya.

Methods and Findings

We enrolled all children <5 years old, hospitalized with diarrhea (≥3 loose stools in 24 hours) at two district hospitals in Nyanza Province, western Kenya. Clinical and demographic information was collected. Stool specimens were tested for bacterial and viral pathogens. Bivariate and multivariable logistic regression analyses were carried out to identify risk factors for death. From May 23, 2005 to May 22, 2007, 1,146 children <5 years old were enrolled; 107 (9%) children died during hospitalization. Nontyphoidal Salmonella were identified in 10% (118), Campylobacter in 5% (57), and Shigella in 4% (42) of 1,137 stool samples; rotavirus was detected in 19% (196) of 1,021 stool samples. Among stools from children who died, nontyphoidal Salmonella were detected in 22%, Shigella in 11%, rotavirus in 9%, Campylobacter in 5%, and S. Typhi in <1%. In multivariable analysis, infants who died were more likely to have nontyphoidal Salmonella (adjusted odds ratio [aOR] = 6·8; 95% CI 3·1–14·9), and children <5 years to have Shigella (aOR = 5·5; 95% CI 2·2–14·0) identified than children who survived. Children who died were less likely to be infected with rotavirus (OR = 0·4; 95% CI 0·2–0·8). Further risk factors for death included being malnourished (aOR = 4·2; 95% CI 2·1–8·7); having oral thrush on physical exam (aOR = 2·3; 95% CI 1·4–3·8); having previously sought care at a hospital for the illness (aOR = 2·2; 95% CI 1·2–3·8); and being dehydrated as diagnosed at discharge/death (aOR = 2·5; 95% CI 1·5–4·1). A clinical diagnosis of malaria, and malaria parasites seen on blood smear, were not associated with increased risk of death. This study only captured in-hospital childhood deaths, and likely missed a substantial number of additional deaths that occurred at home.

Conclusion

Nontyphoidal Salmonella and Shigella are associated with mortality among rural Kenyan children with diarrhea who access a hospital. Improved prevention and treatment of diarrheal disease is necessary. Enhanced surveillance and simplified laboratory diagnostics in Africa may assist clinicians in appropriately treating potentially fatal diarrheal illness. Please see later in the article for the Editors'' Summary     

Malignant Lymphomas of Waldeyer's Ring: Natural History and Survival after Radiotherapy

The natural history of 292 consecutive cases of reticulum cell sarcoma and lymphosarcoma of Waldeyer''s ring and the survival rate after radiotherapy are reported. In our institute since 1928 from 30 to 35% of pharyngeal neoplasms have been lymphomas, and of these 55% have been reticulum cell sarcomas, 21% lymphosarcomas, and 1% Hodgkin''s disease. This high incidence may probably be ascribed to the fact that in all malignant lymphomas, irrespective of the clinical presentation, a systematic biopsy of the whole Waldeyer''s ring was carried out. Pharyngeal lymphomas were confined to Waldeyer''s ring in 19·6% of cases, with initial spread to contiguous cervical nodes in 43·8%, to distant nodes in 24·2%, and to extranodal tissues in 12·4%. Lymphography showed abnormal retroperitoneal lymph nodes in 38·3% of cases. There was gastrointestinal involvement either initially or later in 17·6% of cases. High-energy radiation therapy to both sides of the neck was the treatment of choice for local and regional disease. It achieved a five-year survival rate of 41·9% in the group of 97 patients treated during the past decade. The incidence of relapse (recurrence and new manifestations) was highest in the first year after treatment.     

Non-Heme Iron Absorption and Utilization from Typical Whole Chinese Diets in Young Chinese Urban Men Measured by a Double-Labeled Stable Isotope Technique

BackgroundThis study was to observe the non-heme iron absorption and biological utilization from typical whole Chinese diets in young Chinese healthy urban men, and to observe if the iron absorption and utilization could be affected by the staple food patterns of Southern and Northern China.ResultsNon-heme iron intake values overall, and in the rice and steamed buns groups were 12.8 ±2.1, 11.3±1.3 and 14.3±1.5 mg, respectively; the mean ⁵⁷Fe absorption rates were 11±7%, 13±7%, and 8±4%, respectively; and the mean infused ⁵⁸Fe utilization rates were 85±8%, 84±6%, and 85±10%, respectively. There was no significantly difference in the iron intakes, and ⁵⁷Fe absorption and infused ⁵⁸Fe utilization rates between rice and steamed buns groups (all P>0.05).ConclusionWe present the non-heme iron absorption and utilization rates from typical whole Chinese diets among young Chinese healthy urban men, which was not affected by the representative staple food patterns of Southern and Northern China. This study will provide a basis for the setting of Chinese iron DRIs.     

Glucose metabolism in the superovulated rat ovary in vitro. Effects of luteinizing hormone and the role of glucose metabolism in steroidogenesis

1. Superovulated rat ovary slices from rats treated with 20μg. of luteininzing hormone/100g. body wt. 2hr. before death and from control animals have been incubated in vitro. Output of Δ⁴-3-oxo steroids (0·2μmole/g. wet wt./hr. in control tissue) was linear for 4hr., and was increased by approx. 70% in slices from luteinizing hormone-treated rats. Rate of oxygen consumption (90·0±4·6μmoles/g. wet wt./hr.) was linear for 3hr. and unaltered by luteinizing hormone treatment or addition of glucose (1mg./ml.) to the medium. 2. In slices from control animals, steady-state rate of glucose uptake was 78·0±2·9μg. atoms of carbon/g. wet wt./hr.; steady-state rates of lactate output, pyruvate output and incorporation of [U-¹⁴C]-glucose carbon atoms into carbon dioxide and total lipid extract were 60·7±0·9, 2·4±0·1, 18·0±1·1 and 0·7±0·1μg. atom of carbon/g. wet wt./hr. and accounted for 104·5±1·9% of the glucose uptake. In slices from luteinizing hormone-treated rats, glucose uptake and outputs of lactate, pyruvate and [¹⁴C]carbon dioxide were increased by approx. 25%, and 108·4±3·2% of the glucose uptake could be accounted for. 3. The total lipid extract was separated by thin-layer chromatography and saponification. Of the ¹⁴C incorporated into this fraction during incubation with [U-¹⁴C]glucose 97% was found in the fractions containing glyceride glycerol and less than 3% in the fractions containing sterols, steroids or fatty acids. Appreciable quantities of ¹⁴C were incorporated into these lipid fractions from [1-¹⁴C]acetate. 4. From a consideration of the tissue glycogen content, the specific activities of [¹⁴C]lactate and glucose 6-phosphate (C-1) derived from [1-¹⁴C]-, [6-¹⁴C]- and [U-¹⁴C]-glucose, and the ratio of [¹⁴C]carbon dioxide yields from [1-¹⁴C]glucose and [6-¹⁴C]glucose, it was concluded that there was no appreciable glycogenolysis or flow through the pentose phosphate cycle. 5. In ovary slices from both control and luteinizing hormone-treated animals, glucose in vitro raised the incorporation rate of ¹⁴C from [1-¹⁴C]acetate into sterols and steroids. Luteinizing hormone in vivo stimulated the incorporation rate in vitro but only in the presence of glucose. 6. In slices incubated in medium containing [³H]water, [¹⁴C]sorbitol and glucose (1mg./ml.), the total water space (865±7·1μl./g.) and the extracellular water space (581±22μl./g.) were unchanged by luteinizing hormone treatment in vivo but the glucose space was raised from 540±23·6μl./g. to 639±31·3μl./g. 7. Luteinizing hormone treatment was found to lower the tissue concentration of the hexose monophosphates and to increase the total activity of hexokinase, glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase and possibly of phosphofructokinase. 8. The kinetic properties of a partially purified preparation of phosphofructokinase were found to be qualitatively similar to those from other mammalian tissues. 9. The results are discussed with reference to both the role of glucose metabolism in steroidogenesis and the mechanism by which luteinizing hormone increases the rate of glucose uptake.     

Economical Speed and Energetically Optimal Transition Speed Evaluated by Gross and Net Oxygen Cost of Transport at Different Gradients

The oxygen cost of transport per unit distance (CoT; mL·kg^-1·km^-1) shows a U-shaped curve as a function of walking speed (v), which includes a particular walking speed minimizing the CoT, so called economical speed (ES). The CoT-v relationship in running is approximately linear. These distinctive walking and running CoT-v relationships give an intersection between U-shaped and linear CoT relationships, termed the energetically optimal transition speed (EOTS). This study investigated the effects of subtracting the standing oxygen cost for calculating the CoT and its relevant effects on the ES and EOTS at the level and gradient slopes (±5%) in eleven male trained athletes. The percent effects of subtracting the standing oxygen cost (4.8 ± 0.4 mL·kg^-1·min^-1) on the CoT were significantly greater as the walking speed was slower, but it was not significant at faster running speeds over 9.4 km·h^-1. The percent effect was significantly dependent on the gradient (downhill > level > uphill, P < 0.001). The net ES (level 4.09 ± 0.31, uphill 4.22 ± 0.37, and downhill 4.16 ± 0.44 km·h^-1) was approximately 20% slower than the gross ES (level 5.15 ± 0.18, uphill 5.27 ± 0.20, and downhill 5.37 ± 0.22 km·h^-1, P < 0.001). Both net and gross ES were not significantly dependent on the gradient. In contrast, the gross EOTS was slower than the net EOTS at the level (7.49 ± 0.32 vs. 7.63 ± 0.36 km·h^-1, P = 0.003) and downhill gradients (7.78 ± 0.33 vs. 8.01 ± 0.41 km·h^-1, P < 0.001), but not at the uphill gradient (7.55 ± 0.37 vs. 7.63 ± 0.51 km·h^-1, P = 0.080). Note that those percent differences were less than 2.9%. Given these results, a subtraction of the standing oxygen cost should be carefully considered depending on the purpose of each study.     

Thermal denaturation in acidic solutions of double-helical ribonucleic acid from virus-like particles found in Penicillium chrysogenum. A spectrophotometric study

1. Two species of double-helical RNA isolated from mycelium of Penicillium chrysogenum were titrated with acid at 25°C and 95°C (solvent 0.1m-sodium phosphate buffer). At 25°C denaturation occurred at about pH3. At 95°C in the denatured form cytosine residues titrated as a simple monobasic acid of pK3.9 compared with pK2.5 for the native form at 25°C. 2. On thermal denaturation in neutral and acidic solutions one species of RNA (38% rG·rC) `melted' in three distinct stages, equivalent to a mixture of three species, namely one of about 25% rG·rC, another of about 33% rG·rC and a third of about 46% rG·rC: the relative proportions were 0.25:0.35:0.40. 3. On thermal denaturation in acidic solutions the increase in the fraction of ionized cytosine residues concomitant with the `melting' of rG·rC base pair also affects the spectrum especially at 280nm and serves to enhance the contribution of rG·rC base pairs at this wavelength. The increment in ε_(P) at 280nm on `melting' an rG·rC base pair approaches 53501·mol<sup>−1</sup>·cm<sup>−1</sup> depending on pH, compared with 33501·mol<sup>−1</sup>·cm<sup>−1</sup> at pH7. In contrast ε<sub>(P)</sub> at 280nm is scarcely affected by `melting' rA·rU base pairs or by the protonization of adenine residues. 4. Changes in the spectrum of Escherichia coli rRNA on denaturation in acidic solutions were studied to yield the mole fractions of rA·rU and rG·rC base pairs `melting' at particular pH values.     

Studies on the congenitally goitrous sheep. The iodinated compounds of serum, and circulating thyroid-stimulating hormone

1. A group of normal and congenitally goitrous Merino sheep were investigated to identify the metabolic defect present in the abnormal animals. 2. Protein-bound iodine concentrations of serum from goitrous animals (average 5·7μg./100ml.) were higher than normal (average 4·2μg./100ml.; P 0·001), but the hormonal iodine measured as butanol-extractable ¹³¹I was low in the serum of goitrous (average 40·3% of protein-bound ¹³¹I) compared with that of normal (84·2%; P 0·02) sheep. The non-hormonal iodine of the serum of goitrous sheep appeared to include iodotyrosines and iodinated protein. 3. Starch-gel-electrophoretic separations of sera from normal and goitrous sheep after ¹³¹I injection (100–500μc) showed no qualitative differences in the radioactivity of protein components. No significant differences in thyroxine-binding in vitro by serum proteins of normal and goitrous sheep were observed. 4. The clearance rates of ¹³¹I-labelled iodotyrosines (t_½ 1·2–2·9hr.) and iodothyronines (t_½ 33·5–47·4hr.) were similar in normal and goitrous sheep. 5. The concentration of circulating thyroid-stimulating hormone was significantly higher (P<0·01 in three sheep, P<0·05 in one sheep) in goitrous sheep. 6. The congenital goitre appears to be due to compensatory hypertrophy of the gland resulting from an inability to synthesize an adequate supply of thyroid hormone.     

Restless Legs Syndrome,with Particular Reference to its Occurrence After Gastric Surgery

There is a higher incidence of restless legs syndrome (Ekbom''s syndrome) in patients after gastric surgery (11·3%) and with diabetes mellitus (17·0%) and uraemia (17·3%) than in patients who have been diagnosed as having a psychonoeurosis (4·0%) and in controls (2·0%). Three patients with malabsorption syndrome complained of restless legs, but these patients had abnormal neurological signs. The incidence after gastric surgery and in diabetes mellitus and uraemia remained high even when patients with any abnormal neurological signs were excluded.     

The metabolism of methylcyclohexane

1. When [U-¹⁴C]methylcyclohexane is fed to rabbits (dose 2–2·5m-moles/kg. body wt.), 65% of the radioactivity is excreted in the urine as metabolites, 0·5% appears in the faeces and about 15% in the expired air, some 4–5% remaining in the body in about 60hr. after dosing. The 15% of the dose appearing in the expired air consists of unchanged methylcyclohexane (10%) and ¹⁴CO₂ (5%). The low output of ¹⁴CO₂ shows that reactions leading to complete oxidation of methylcyclohexane are of minor importance. 2. The main metabolite found in the urine was the glucuronide of trans-4-methylcyclohexanol which was isolated. Seven methylcyclohexanols were found in the urine as conjugated glucuronides. The amounts of these were determined by isotope dilution to be as follows: cis-2-, 0·6%; trans-2-, 1·2%; cis-3-, 11·5%; trans-3-, 10·5%; cis-4-, 2·4%; trans-4-methylcyclohexanol, 14·7%, cyclohexylmethanol, 0·3%. No 1-methylcyclohexanol was found. There was evidence also that a small amount (approx. 1%) of the hydrocarbon aromatized to benzoic acid, probably via cyclohexylmethanol and cyclohexane-carboxylic acid. 3. The pattern of hydroxylation and the various amounts of the isomers found suggest that the hydroxylation in vivo of methylcyclohexane is dependent on steric factors in the molecule, hydroxylation occurring to the greatest extent at the carbon atom furthest away from the methyl group.     

Artificial asymmetric warming reduces nectar yield in a Tibetan alpine species of Asteraceae

Background and Aims Asymmetric warming is one of the distinguishing features of global climate change, in which winter and night-time temperatures are predicted to increase more than summer and diurnal temperatures. Winter warming weakens vernalization and hence decreases the potential to flower for some perennial herbs, and night warming can reduce carbohydrate concentrations in storage organs. This study therefore hypothesized that asymmetric warming should act to reduce flower number and nectar production per flower in a perennial herb, Saussurea nigrescens, a key nectar plant for pollinators in Tibetan alpine meadows.Methods A long-term (6 years) warming experiment was conducted using open-top chambers placed in a natural meadow and manipulated to achieve asymmetric increases in temperature, as follows: a mean annual increase of 0·7 and 2·7 °C during the growing and non-growing seasons, respectively, combined with an increase of 1·6 and 2·8 °C in the daytime and night-time, respectively, from June to August. Measurements were taken of nectar volume and concentration (sucrose content), and also of leaf non-structural carbohydrate content and plant morphology.Key Results Six years of experimental warming resulted in reductions in nectar volume per floret (64·7 % of control), floret number per capitulum (8·7 %) and capitulum number per plant (32·5 %), whereas nectar concentration remained unchanged. Depletion of leaf non-structural carbohydrates was significantly higher in the warmed than in the ambient condition. Overall plant density was also reduced by warming, which, when combined with reductions in flower development and nectar volumes, led to a reduction of ∼90 % in nectar production per unit area.Conclusions The negative effect of asymmetric warming on nectar yields in S. nigrescens may be explained by a concomitant depletion of leaf non-structural carbohydrates. The results thus highlight a novel aspect of how climate change might affect plant–pollinator interactions and plant reproduction via induction of allocation shifts for plants growing in communities subject to asymmetric warming.