Safety of non-ablative fractional laser for acne scars within 1 month after treatment with oral isotretinoin: A randomized split-face controlled trial.

BACKGROUND AND OBJECTIVE: Based on reports of poor wound healing and scarring, it is currently recommended that patients wait 6 months after completion of oral isotretinoin therapy before the safe initiation of laser treatment. Our aim was to evaluate the safety of non-ablative fractional laser (NAFL) treatment for acne scars within 1 month after isotretinoin therapy. STUDY DESIGN/METHODS: This was a randomized split-face controlled trial involving 10 patients with acne scars who had completed isotretinoin treatment. All patients received three treatments each spaced 4 weeks apart with an erbium-doped 1550 nm NAFL on one side of the face within 1 month after isotretinoin therapy. The untreated side acted as a control. Wound healing and adverse effects as well as acne scar improvement were evaluated by two blinded dermatologists. RESULTS: All patients demonstrated normal wound healing post NAFL treatments, and neither hypertrophic scars nor keloids were observed. Acne scar improvement was satisfactory. CONCLUSION: NAFL treatment for acne scarring appears to be well tolerated within 1 month of completing isotretinoin treatment. Dermatologists should reevaluate the current recommendation to wait 6 months after isotretinoin treatment for acne scar revision with lasers. Other larger studies are necessary to further challenge this dogma. Lasers Surg. Med. 49:886-890, 2017. © 2017 Wiley Periodicals, Inc.

Limited linkages of aboveground and belowground phenology: A study in grape.

PREMISE OF THE STUDY: Plant phenology influences resource utilization, carbon fluxes, and interspecific interactions. Although controls on aboveground phenology have been studied to some degree, controls on root phenology are exceptionally poorly understood. METHODS: We used minirhizotrons to examine the timing of grape root production over 5 yr in Fredonia, New York, USA, in a humid continental climate; and over 3 yr in Oakville, California, USA, in a Mediterranean climate. We used data from previous experiments to examine the relationship of root phenology with aboveground phenology. We compared interannual variability in root and shoot growth and determined the influence of abiotic factors on the timing of root initiation, peak root standing crop, peak root growth rate, and cessation of root growth. KEY RESULTS: Root phenology was not tightly coupled with aboveground phenological periods. Both sites typically had one yearly root flush and high interannual variability in root growth. Root phenology was more variable in California than in New York. In this and other published studies, interannual variation in root phenology was greater than variation in aboveground phenology. The three phenological phases of root growth-root initiation, peak root growth, and root cessation-were related to different suites of abiotic factors. CONCLUSIONS: Root phenology is highly variable among years. Analysis of potential controlling factors over several years suggest that belowground phenological phases should be analyzed separately from each other. If aboveground grape phenology responds differently than belowground phenology to changes in air temperature, global warming may further uncouple the timing of aboveground and belowground growth.

A perforating pilomatricomal horn on the arm of an 11-year-old girl.

Cutaneous horns are uncommon in adults and rare in the pediatric population. Although verruca vulgaris, solar keratosis, and squamous cell carcinoma are more common entities that can present as cutaneous horns in the general population, conditions such as molluscum contagiosum, juvenile xanthgranuloma, and pyogenic granuloma have been reported causes in the pediatric population. We present a case of a perforating pilomatricoma presenting as a cutaneous horn in an 11 year old girl.

Hyperbaric Oxygen for Lower Limb Trauma (HOLLT): an international multi-centre randomised clinical trial.

INTRODUCTION: Hyperbaric oxygen treatment (HBOT) is sometimes used in the management of open fractures and severe soft tissue crush injury, aiming to reduce complications and improve outcomes. METHODS: Patients with open tibial fractures were randomly assigned within 48 hours of injury to receive standard trauma care or standard care plus 12 sessions of HBOT. The primary outcome was the incidence of necrosis or infection or both occurring within 14 days of injury. RESULTS: One-hundred and twenty patients were enrolled. Intention to treat primary outcome occurred in 25/58 HBOT assigned patients and 34/59 controls (43% vs 58%, odds ratio (OR) 0.55, 95% confidence interval (CI) 0.25 to 1.18, P = 0.12). Tissue necrosis occurred in 29% of HBOT patients and 53% of controls (OR 0.35, 95% CI 0.16 to 0.78, P = 0.01). There were fewer late complications in patients receiving HBOT (6/53 vs 18/52, OR 0.22, 95% CI 0.08 to 0.64, P = 0.007) including delayed fracture union (5/53 vs 13/52, OR 0.31, 95% CI 0.10 to 0.95, P = 0.04). Quality of life measures at one and two years were superior in HBOT patients. The mean score difference in short form 36 was 2.90, 95% CI 1.03 to 4.77, P = 0.002, in the short musculoskeletal function assessment (SMFA) was 2.54, 95% CI 0.62 to 4.46, P = 0.01; and in SMFA daily activities was 19.51, 95% CI 0.06 to 21.08, P = 0.05. CONCLUSIONS: In severe lower limb trauma, early HBOT reduces tissue necrosis and the likelihood of long-term complications, and improves functional outcomes. Future research should focus on optimal dosage and whether HBOT has benefits for other injury types.

Seasonal changes of whole root system conductance by a drought-tolerant grape root system.

The role of root systems in drought tolerance is a subject of very limited information compared with above-ground responses. Adjustments to the ability of roots to supply water relative to shoot transpiration demand is proposed as a major means for woody perennial plants to tolerate drought, and is often expressed as changes in the ratios of leaf to root area (A(L):A(R)). Seasonal root proliferation in a directed manner could increase the water supply function of roots independent of total root area (A(R)) and represents a mechanism whereby water supply to demand could be increased. To address this issue, seasonal root proliferation, stomatal conductance (g(s)) and whole root system hydraulic conductance (k(r)) were investigated for a drought-tolerant grape root system (Vitis berlandieri×V. rupestris cv. 1103P) and a non-drought-tolerant root system (Vitis riparia×V. rupestris cv. 101-14Mgt), upon which had been grafted the same drought-sensitive clone of Vitis vinifera cv. Merlot. Leaf water potentials (ψ(L)) for Merlot grafted onto the 1103P root system (-0.91±0.02 MPa) were +0.15 MPa higher than Merlot on 101-14Mgt (-1.06±0.03 MPa) during spring, but dropped by approximately -0.4 MPa from spring to autumn, and were significantly lower by -0.15 MPa (-1.43±0.02 MPa) than for Merlot on 101-14Mgt (at -1.28±0.02 MPa). Surprisingly, g(s) of Merlot on the drought-tolerant root system (1103P) was less down-regulated and canopies maintained evaporative fluxes ranging from 35-20 mmol vine(-1) s(-1) during the diurnal peak from spring to autumn, respectively, three times greater than those measured for Merlot on the drought-sensitive rootstock 101-14Mgt. The drought-tolerant root system grew more roots at depth during the warm summer dry period, and the whole root system conductance (k(r)) increased from 0.004 to 0.009 kg MPa(-1) s(-1) during that same time period. The changes in k(r) could not be explained by xylem anatomy or conductivity changes of individual root segments. Thus, the manner in which drought tolerance was conveyed to the drought-sensitive clone appeared to arise from deep root proliferation during the hottest and driest part of the season, rather than through changes in xylem structure, xylem density or stomatal regulation. This information can be useful to growers on a site-specific basis in selecting rootstocks for grape clonal material (scions) grafted to them.

Microcystic adnexal carcinoma: the first reported congenital case.

Microcystic adenexal carcinoma is a rare, locally aggressive, malignant appendage tumor also known as sclerosing sweat duct carcinoma. Since widespread recognition of microcystic adenexal carcinoma as a distinct clinicopathologic entity, approximately 300 total cases have been reported in the literature, with only eight previous cases reported in children under the age of 18, with no reported cases in patients younger than 6 years old. Our patient is unique in that the lesion was present at birth, making this the youngest case of microcystic adenexal carcinoma reported.

Intensive fertilizer use increases orchard N cycling and lowers net global warming potential.

Nitrogen (N) fertilizer use has simultaneously increased global food production and N losses, resulting in degradation of water quality and climate pollution. A better understanding of N application rates and crop and environmental response is needed to optimize management of agroecosystems. Here we show an orchard agroecosystem with high N use efficiency promoted substantial gains in carbon (C) storage, thereby lowering net global warming potential (GWP). We conducted a 5-year whole-system analysis comparing reduced (224 kg N ha-1 yr-1) and intensive (309 kg N ha-1 yr-1) fertilizer N rates in a California almond orchard. The intensive rate increased net primary productivity (Mg C ha-1) and significantly increased N productivity (kg N ha-1) and net N mineralization (mg N kg-1 soil d-1). Use of 15N tracers demonstrated short and long-term mechanisms of soil N retention. These low organic matter soils (0.3-0.5%) rapidly immobilized fertilizer nitrate within 36 h of N application and 15N in tree biomass recycled back into soil organic matter over five years. Both fertilizer rates resulted in high crop and total N recovery efficiencies of 90% and 98% for the reduced rate, and 72% and 80% for the intensive rate. However, there was no difference in the proportion of N losses to N inputs due to a significant gain in soil total N (TN) in the intensive rate. Higher soil TN significantly increased net N mineralization and a larger gain in soil organic carbon (SOC) from the intensive rate offset nitrous oxide (N2O) emissions, leading to significantly lower net GWP of -1.64 Mg CO2-eq ha-1 yr-1 compared to -1.22 Mg CO2-eq ha-1 yr-1 for the reduced rate. Our study demonstrates increased N cycling and climate mitigation from intensive fertilizer N use in this orchard agroecosystem, implying a fundamentally different result than seen in conventional annual cropping systems.

Nutrient Storage in the Perennial Organs of Deciduous Trees and Remobilization in Spring - A Study in Almond (Prunus dulcis) (Mill.) D. A. Webb.

The annual dynamics of whole mature almond tree nutrient remobilization in spring and the accumulation of nutrients in perennial tissues during the year were determined by sequential coring, tissue sampling, nutrient analysis, whole tree excavation and biomass estimation for trees grown under four nitrogen rate treatments 140 kg ha-1 N (N140), 224 kg ha-1 N (N224), 309 kg ha-1 N (N309), and 392 kg ha-1 N (N392) over 2 years. Whole tree perennial organ N content was greatest in dormancy then declined through bud swell, flowering and fruit set, achieving the lowest total whole tree nutrient content of perennial organs by March 12 [12-14 days after full bloom (DAFB)] coincident with 60-70% leaf expansion. During this period no net increment in whole tree N content (annual plus perennial N) was observed indicating that tree demand for N for bud break, flowering, fruit set and leaf out was met by remobilized stored N and that there was no net N uptake from soil. Remobilizable N increased with increasing N application up to N309 and was maximal at 44.4 ± 4 kg ha-1 and 37.5 ± 5.7 kg ha-1 for the optimally fertilized N309 in 2012 and 2013 respectively. Net increases in perennial organ N (stored N) commenced 41 DAFB and continued through full leaf abscission at 249 DAFB. Total annual N increment in perennial organs varied from 25 to 60 kg ha-1 and was strongly influenced by N rate and tree yield. N remobilized from senescing leaves contributed from 11 to 15.5 ± 0.6 kg ha-1 to perennial stored N. Similar patterns of nutrient remobilization and storage were observed for P, K, and S with maximal whole tree perennial storage occurring during dormancy and remobilization of that stored P, K, S to support annual tree demands through to fruit set and 70-100% leaf development. Net annual increment in perennial organ P, K, S commenced 98 DAFB and continued through full leaf abscission at 249 DAFB. Organ specific contribution to remobilizable and stored nutrients changes over the growing season are presented. Details of the pattern of perennial organ nutrient allocation, storage, and remobilization provides a framework for the optimal management of nutrients in almond with relevance for other deciduous tree species.

Floodplain soil and its bacterial composition are strongly affected by depth.

We studied bacterial abundance and community structure of five soil cores using high-throughput sequencing of the 16S rRNA gene. Shifts in the soil bacterial composition were more pronounced within a vertical profile than across the landscape. Soil organic carbon (SOC) and nitrogen (N) concentrations decreased exponentially with soil depth and revealed a buried carbon-rich horizon between 0.8 and 1.3 m across all soil cores. This buried horizon was phylogenetically similar to its surrounding subsoils supporting the idea that the type of carbon, not necessarily the amount of carbon was driving the apparent similarities. In contrast to other studies, Nitrospirae was one of our major phyla with relatively high abundances throughout the soil profile except for the surface soil. Although depth is the major driver shaping soil bacterial community structure, positive correlations with SOC and N concentrations, however, were revealed with the bacterial abundance of Acidobacteria, one of the major, and Gemmatimonadetes, one of the minor phyla in our study. Our study showed that bacterial diversity in soils below 2.0 m can be still as high if not higher than in the above laying subsurface soil suggesting that various bacteria throughout the soil profile influence major biogeochemical processes in floodplain soils.

Human-induced and natural carbon storage in floodplains of the Central Valley of California.

Active floodplains can putatively store large amounts of organic carbon (SOC) in subsoils originating from catchment erosion processes with subsequent floodplain deposition. Our study focussed on the assessment of SOC pools associated with alluvial floodplain soils that are affected by human-induced changes in floodplain deposition and in situ SOC mineralisation due to land use change and drainage. We evaluated depth-dependent SOC contents based on 23 soil cores down to 3 m and 10 drillings down to 7 m in a floodplain area of the lower Cosumnes River. An estimate of 266 Mg C ha-1 or about 59% of the entire SOC stored within the 7 m profiles was found in the upper 2 m. Most profiles (n = 25) contained discrete buried A horizons at depths of approximately 0.8 m. These profiles had up to 130% higher SOC stocks. The mean δ13C of all deep soil profiles clearly indicated that arable land use has already altered the stable isotopic signature in the first meter of the profile. Radiocarbon dating showed that the 14C age in the buried horizon was younger than in overlaying soils indicating a substantial sedimentation phase for the overlaying soils. An additional analysis of total mercury contents in the soil profiles indicated that this sedimentation was associated with upstream hydraulic gold mining after the 1850s. In summary, deep alluvial soils in floodplains store large amounts of SOC not yet accounted for in global carbon models. Historic data give evidence that large amounts of sediment were transported into the floodplains of most rivers of the Central Valley and deposited over organically rich topsoil, which promoted the stabilization of SOC, and needs to be considered to improve our understanding of the human-induced interference with C cycling.

Root foraging in response to heterogeneous soil moisture in two grapevines that differ in potential growth rate.

* Linkages between plant growth rate and root responses to soil moisture heterogeneity were investigated. * Root dynamics were studied using genetically identical shoots (Vitis vinifera cv. Merlot) with genetically distinct root systems that promote higher (HSV) and lower (LSV) shoot growth rates (1103P and 101-14 Mgt, respectively). Three quantities of irrigation replenished different amounts of evapotranspiration (0, 40 and 100%ET(c)) in a California vineyard. * Roots of HSV vines exhibited more plasticity, as indicated by greater preferential growth in irrigated soil during the summer, and a larger shift in root diameter with a change in soil moisture than LSV vines. Higher tolerance of low soil moisture was not observed in LSV roots--root survivorship was similar for the two rootstocks. LSV vines produced a large fraction of its roots during the winter months and increased root density over the study, while HSV vines produced roots mainly in summer and only exhibited a high initial peak in root biomass in the first year. * These results demonstrated that a plant of higher vigor has greater morphological plasticity in response to lateral heterogeneity in soil moisture but similar tolerance to moisture stress as indicated by root survivorship in dry soil.

Identifying and acting on potentially inappropriate care? Inadequacy of current hospital coding for this task.

INTRODUCTION: Recent Australian attempts to facilitate disinvestment in healthcare, by identifying instances of 'inappropriate' care from large Government datasets, are subject to significant methodological flaws. Amongst other criticisms has been the fact that the Government datasets utilized for this purpose correlate poorly with datasets collected by relevant professional bodies. Government data derive from official hospital coding, collected retrospectively by clerical personnel, whilst professional body data derive from unit-specific databases, collected contemporaneously with care by clinical personnel. AIM: Assessment of accuracy of official hospital coding data for hyperbaric services in a tertiary referral hospital. METHODS: All official hyperbaric-relevant coding data submitted to the relevant Australian Government agencies by the Royal Hobart Hospital, Tasmania, Australia for financial year 2010-2011 were reviewed and compared against actual hyperbaric unit activity as determined by reference to original source documents. RESULTS: Hospital coding data contained one or more errors in diagnoses and/or procedures in 70% of patients treated with hyperbaric oxygen that year. Multiple discrete error types were identified, including (but not limited to): missing patients; missing treatments; 'additional' treatments; 'additional' patients; incorrect procedure codes and incorrect diagnostic codes. Incidental observations of errors in surgical, anaesthetic and intensive care coding within this cohort suggest that the problems are not restricted to the specialty of hyperbaric medicine alone. Publications from other centres indicate that these problems are not unique to this institution or State. CONCLUSIONS: Current Government datasets are irretrievably compromised and not fit for purpose. Attempting to inform the healthcare policy debate by reference to these datasets is inappropriate. Urgent clinical engagement with hospital coding departments is warranted.

Identifying and acting on inappropriate metadata: a critique of the Grattan Institute Report on questionable care in Australian hospitals.

INTRODUCTION: In an era of ever-increasing medical costs, the identification and prohibition of ineffective medical therapies is of considerable economic interest to healthcare funding bodies. Likewise, the avoidance of interventions with an unduly elevated clinical risk/benefit ratio would be similarly advantageous for patients. Regrettably, the identification of such therapies has proven problematic. A recent paper from the Grattan Institute in Australia (identifying five hospital procedures as having the potential for disinvestment on these grounds) serves as a timely illustration of the difficulties inherent in non-clinicians attempting to accurately recognize such interventions using non-clinical, indirect or poorly validated datasets. AIM: To evaluate the Grattan Institute report and associated publications, and determine the validity of their assertions regarding hyperbaric oxygen treatment (HBOT) utilisation in Australia. METHODS: Critical analysis of the HBOT metadata included in the Grattan Institute study was undertaken and compared against other publicly available Australian Government and independent data sources. The consistency, accuracy and reproducibility of data definitions and terminology across the various publications were appraised and the authors' methodology was reviewed. Reference sources were examined for relevance and temporal eligibility. RESULTS: Review of the Grattan publications demonstrated multiple problems, including (but not limited to): confusing patient-treatments with total patient numbers; incorrect identification of 'appropriate' vs. 'inappropriate' indications for HBOT; reliance upon a compromised primary dataset; lack of appropriate clinical input, muddled methodology and use of inapplicable references. These errors resulted in a more than seventy-fold over-estimation of the number of patients potentially treated inappropriately with HBOT in Australia that year. CONCLUSION: Numerous methodological flaws and factual errors have been identified in this Grattan Institute study. Its conclusions are not valid and a formal retraction is required.

From berries to blocks: carbon stock quantification of a California vineyard.

BACKGROUND: Quantifying terrestrial carbon (C) stocks in vineyards represents an important opportunity for estimating C sequestration in perennial cropping systems. Considering 7.2 M ha are dedicated to winegrape production globally, the potential for annual C capture and storage in this crop is of interest to mitigate greenhouse gas emissions. In this study, we used destructive sampling to measure C stocks in the woody biomass of 15-year-old Cabernet Sauvignon vines from a vineyard in California's northern San Joaquin Valley. We characterize C stocks in terms of allometric variation between biomass fractions of roots, aboveground wood, canes, leaves and fruits, and then test correlations between easy-to-measure variables such as trunk diameter, pruning weights and harvest weight to vine biomass fractions. Carbon stocks at the vineyard block scale were validated from biomass mounds generated during vineyard removal. RESULTS: Total vine C was estimated at 12.3 Mg C ha-1, of which 8.9 Mg C ha-1 came from perennial vine biomass. Annual biomass was estimated at 1.7 Mg C ha-1 from leaves and canes and 1.7 Mg C ha-1 from fruit. Strong, positive correlations were found between the diameter of the trunk and overall woody C stocks (R2 = 0.85), pruning weights and leaf and fruit C stocks (R2 = 0.93), and between fruit weight and annual C stocks (R2 = 0.96). CONCLUSIONS: Vineyard C partitioning obtained in this study provides detailed C storage estimations in order to understand the spatial and temporal distribution of winegrape C. Allometric equations based on simple and practical biomass and biometric measurements could enable winegrape growers to more easily estimate existing and future C stocks by scaling up from berries and vines to vineyard blocks.

Deep carbon storage potential of buried floodplain soils.

Soils account for the largest terrestrial pool of carbon and have the potential for even greater quantities of carbon sequestration. Typical soil carbon (C) stocks used in global carbon models only account for the upper 1 meter of soil. Previously unaccounted for deep carbon pools (>1 m) were generally considered to provide a negligible input to total C contents and represent less dynamic C pools. Here we assess deep soil C pools associated with an alluvial floodplain ecosystem transitioning from agricultural production to restoration of native vegetation. We analyzed the soil organic carbon (SOC) concentrations of 87 surface soil samples (0-15 cm) and 23 subsurface boreholes (0-3 m). We evaluated the quantitative importance of the burial process in the sequestration of subsurface C and found our subsurface soils (0-3 m) contained considerably more C than typical C stocks of 0-1 m. This deep unaccounted soil C could have considerable implications for global C accounting. We compared differences in surface soil C related to vegetation and land use history and determined that flooding restoration could promote greater C accumulation in surface soils. We conclude deep floodplain soils may store substantial quantities of C and floodplain restoration should promote active C sequestration.

Effects of land use on soil respiration: conversion of oak woodlands to vineyards.

We examined constraints on soil CO2 respiration in natural oak woodlands, and adjacent vineyards that were converted approximately 30 yr ago from oak woodlands, in the Oakville Region of Napa Valley, California. All sites were located on the same soil type, a Bale (variant) gravelly loam (fine-loamy, mixed, superactive, thermic Cumulic Ultic Haploxeroll) and dominated by C3 vegetation. Seasonal soil CO2 efflux was greatest at the oak woodland sites, although during the summer drought the rates of soil CO2 efflux measured from oak sites were generally similar to those measured from the vineyards. Soil profile CO2 concentrations at the oak woodland sites were lower below 15 cm despite higher CO2 efflux rates. Soil gas diffusion coefficients for oak sites were larger than for vineyard sites, and this indicated that the apparent discrepancy in soil profile carbon dioxide concentration ([CO2]) may be caused by a diffusion limitation. Soil profile [CO2] and delta13C values showed substantial temporal changes over the course of a year. Vineyard soil CO2 was more depleted in 13CO2 below 25 cm in the soil profile during the active growing season as indicated by more negative delta13C ratios. This result indicated that different C sources were being oxidized in vineyard soils. Annual C losses were less from vineyard soils (7.02 +/- 0.58 Mg C ha(-1) yr(-1)) as compared to oak soils (15.67 +/- 1.44 Mg C ha(-1) yr(-1)), and both were comparable to losses reported in previous investigations.

Erratum.

In the paper: Smart DR, Van den Broek C, Nishi R, Cooper PD, Eastman D. Field validation of Tasmania's aquaculture industry bounce-diving schedules using Doppler analysis of decompression stress. Diving Hyperb Med. 2014 September:44(3):124-136. Numbering in the reference list starts at 3, whereas it should start from number 1. The numbering sequence in the text is correct.

Kinetics of ammonium and nitrate uptake among wild and cultivated tomatoes.

Concentration dependence of net ammonium and nitrate uptake was monitored for a cultivar of tomato, Lycopersicon esculentum, and two accessions of a neotropical wild relative, L. hirsutum. The kinetics of net NH 4+ uptake differed among these taxa and were not dependent on the ionic composition of the nutrient solution. The kinetics of net NO 3- uptake were dependent on the composition of the nutrient solution; the presence of NH 4+ or Cl- enhanced net NO 3- uptake for the cultivated species and for a highland accession of the wild species. The capacity for net NO 3- uptake was greater than the capacity for net NH 4+ uptake in all three taxa; the proportion of NO 3- to NH 4+ absorbed was much greater for the wild taxa. Our data suggest that NO 3- may be a more important source of mineral nitrogen than NH 4+ for these tropical taxa.

Exposure to elevated carbon dioxide concentration in the dark lowers the respiration quotient of Vitis cane wood.

Cane cuttings of the grapevine rootstock Vitis rupestris Scheele x V. riparia Michx. cv. 3309 Couderc were brought out of endodormancy by warming at 30 degrees C. Cane pieces (12 to 13 cm long) with nodes containing a primary bud were placed in a gas exchange system and monitored for net respiratory fluxes of CO2 and O2. Grapevine respiration rates expressed on a wood volume basis were 1.4 to 3.4 mmol CO2 or O2 m-3s-1, which is higher than stem respiration rates reported for many other woody taxa but similar to rates measured for ecodormant buds of other Vitis species. Passive water loss from canes was 0.7 to 1.2 mmol H2O m-3s-1. During a 7-day period, nonstructural carbohydrate concentrations in cane wood declined only slightly, whereas sucrose was nearly completely consumed. When ambient CO2 concentration ([CO2]) was raised from 300 to 750 micro molmol-1 and then 2000 micromol mol-1, net CO2 exchange rates declined by 5.9 +/- 0.6 and then 11.0 +/- 0.6%, whereas net O2 consumption rates remained about constant. The mean respiration quotient (net CO2/O2 flux) for canes with intact ecodormant buds was 0.99 +/- 0.03 when the [CO2] was 300 micromol mol-1, and decreased to 0.87 +/- 0.03 and 0.088 +/- 0.02 when the [CO2] was increased to 750 and 2000 micromol mol-1, respectively. The results support the hypothesis that, in Vitis canes, inhibition of respiratory CO2 efflux in response to high [CO2] is an indirect consequence of non-photosynthetic carboxylation reactions, and not a result of inhibition of respiratory metabolism.