Detailed in situ leaf energy budget permits the assessment of leaf aerodynamic resistance as a key to enhance non-evaporative cooling under drought

The modulation of the leaf energy budget components to maintain optimal leaf temperature are fundamental aspects of plant functioning and survival. Better understanding these aspects becomes increasingly important under a drying and warming climate when cooling through evapotranspiration (E) is suppressed. Combining novel measurements and theoretical estimates, we obtained unusually comprehensive twig-scale leaf energy budgets under extreme field conditions in droughted (suppressed E) and non-droughted (enhanced E) plots of a semi-arid pine forest. Under the same high mid-summer radiative load, leaf cooling shifted from relying on nearly equal contributions of sensible (H) and latent (LE) energy fluxes in non-droughted trees to relying almost exclusively on H in droughted ones, with no change in leaf temperature. Relying on our detailed leaf energy budget, we could demonstrate that this is due to a 2× reduction in leaf aerodynamic resistance. This capability for LE-to-H shift in leaves of mature Aleppo pine trees under droughted field conditions without increasing leaf temperature is likely a critical factor in the resilience and relatively high productivity of this important Mediterranean tree species under drying conditions.

The importance of tree internal water storage under drought conditions

Global warming and drying trends, as well as the increase in frequency and intensity of droughts, may have unprecedented impacts on various forest ecosystems. We assessed the role of internal water storage (WS) in drought resistance of mature pine trees in the semi-arid Yatir Forest. Transpiration (T), soil moisture and sap flow (SF) were measured continuously, accompanied by periodical measurements of leaf and branch water potential (Ψleaf) and water content (WC). The data were used to parameterize a tree hydraulics model to examine the impact of WS capacitance on the tree water relations. The results of the continuous measurements showed a 5-h time lag between T and SF in the dry season, which peaked in the early morning and early afternoon, respectively. A good fit between model results and observations was only obtained when the empirically estimated WS capacitance was included in the model. Without WS during the dry season, Ψleaf would drop below a threshold known to cause hydraulic failure and cessation of gas exchange in the studied tree species. Our results indicate that tree WS capacitance is a key drought resistance trait that could enhance tree survival in a drying climate, contributing up to 45% of the total daily transpiration during the dry season.

The rate of occult nodal metastasis in submandibular gland malignancies: A case series and meta-analysis

OBJECTIVE

Submandibular gland (SMG) malignancies are exceedingly rare. Lymph node metastasis is one of the most important determinants of outcome in SMG malignancies. The aim of this study was to investigate the overall rate of occult neck nodal metastasis in SMG malignancies.

STUDY DESIGN

The study design is a meta-analysis of all studies on patients with a primary SMG malignancy, without evidence of neck nodal metastasis, who underwent an elective neck dissection (END). The search strategy identified 158 papers that appeared in print from January 1980 to July 2020. All eligible patients from the Tel-Aviv Medical Center were analyzed and consolidated into a case series. A total of 12 retrospective studies that included 306 suitable patients met inclusion criteria.

RESULTS

The risk for occult metastasis in primary SMG malignancies was 0.0% to 50.0%, with a fixed effect model of 19.52% (95% CI, 14.9%-24.5%). The analyzed studies included a wide range of pathologies. The most common malignancies were adenoid cystic carcinoma and mucoepidermoid carcinoma.

CONCLUSIONS

The overall rate of occult neck metastasis in SMG malignancies is relatively high, and an END should be the default intervention in these cases. An END is unwarranted in tumors judged clinically to be low stage and low grade.

Bark Transpiration Rates Can Reach Needle Transpiration Rates Under Dry Conditions in a Semi-arid Forest

Drought can cause tree mortality through hydraulic failure and carbon starvation. To prevent excess water loss, plants typically close their stomata before massive embolism formation occurs. However, unregulated water loss through leaf cuticles and bark continues after stomatal closure. Here, we studied the diurnal and seasonal dynamics of bark transpiration and how it is affected by tree water availability. We measured continuously for six months water loss and CO₂ efflux from branch segments and needle-bearing shoots in Pinus halepensis growing in a control and an irrigation plot in a semi-arid forest in Israel. Our aim was to find out how much passive bark transpiration is affected by tree water status in comparison with shoot transpiration and bark CO₂ emission that involve active plant processes, and what is the role of bark transpiration in total tree water use during dry summer conditions. Maximum daily water loss rate per bark area was 0.03-0.14 mmol m^-2 s^-1, which was typically ~76% of the shoot transpiration rate (on leaf area basis) but could even surpass the shoot transpiration rate during the highest evaporative demand in the control plot. Irrigation did not affect bark transpiration rate. Bark transpiration was estimated to account for 64-78% of total water loss in drought-stressed trees, but only for 6-11% of the irrigated trees, due to differences in stomatal control between the treatments. Water uptake through bark was observed during most nights, but it was not high enough to replenish the lost water during the day. Unlike bark transpiration, branch CO₂ efflux decreased during drought due to decreased metabolic activity. Our results demonstrate that although bark transpiration represents a small fraction of the total water loss through transpiration from foliage in non-stressed trees, it may have a large impact during drought.

Evidence for efficient nonevaporative leaf-to-air heat dissipation in a pine forest under drought conditions

The drier climates predicted for many regions will result in reduced evaporative cooling, leading to leaf heat stress and enhanced mortality. The extent to which nonevaporative cooling can contribute to plant resilience under these increasingly stressful conditions is not well known at present. Using a novel, high accuracy infrared system for the continuous measurement of leaf temperature in mature trees under field conditions, we assessed leaf-to-air temperature differences (ΔT_leaf-air ) of pine needles during drought. On mid-summer days, ΔT_leaf-air remained < 3°C, both in trees exposed to summer drought and in those provided with supplemental irrigation, which had a more than 10-fold higher transpiration rate. The nonevaporative cooling in the drought-exposed trees must be facilitated by low resistance to heat transfer, generating a large sensible heat flux, H. ΔT_leaf-air was weakly related to variations in the radiation load and mean wind speed in the lower part of the canopy, but was dependent on canopy structure and within-canopy turbulence that enhanced the H. Nonevaporative cooling is demonstrated as an effective cooling mechanism in needle-leaf trees which can be a critical factor in forest resistance to drying climates. The generation of a large H at the leaf scale provides a basis for the development of the previously identified canopy-scale 'convector effect'.

Three-dimensional intraoperative computed tomography imaging for zygomatic fracture repair

Objectives

Zygomatic complex (ZMC) fractures comprise up to 40% of all facial fractures. Misaligned bone fragments and misplaced fixation hardware traditionally detected postoperatively on plain radiographs of the skull might require re-operation. The intraoperative O-Arm (Medtronic, USA) is a three-dimensional (3D) computed tomographic imaging system.

Materials and Methods

This retrospective single-center study evaluated the utility of O-Arm scanning during corrective surgeries for ZMC and zygomatic arch (ZA) fractures from 2018 to 2020. Three females and 16 males (mean age, 31.52 years; range, 22-48 years) were included. Fracture instability (n=6) and facial deformity (n=15) were the most frequent indications for intraoperative 3D O-Arm scan.

Results

The images demonstrated that all fracture lines were properly reduced and fixed. Another scan performed at the end of the fixation or reduction stage, however, revealed suboptimal results in five of the 19 cases, and further reduction and fixation of the fracture lines were required.

Conclusion

Implementation of an intraoperative O-Arm system in ZMC and ZA fracture surgeries assists in obtaining predictable and accurate results and obviates the need for revision surgeries. The device should be considered for precise operations such as ZMC fracture repairs.

Surgical management of odontogenic cysts involving the maxillary sinus- a retrospective study

OBJECTIVE

To describe our strategy for the management of odontogenic cysts involving the maxillary sinus, and to define the role of transnasal endoscopic sinus surgery in the treatment algorithm.

METHODS

A retrospective study was conducted. Included were all consecutive patients with odontogenic cysts involving the maxillary sinus who were treated in a single medical center between 2011 and 2019. Their medical records were reviewed for demographic data, preoperative presentation, surgical approach, final pathology, and postoperative course. Odontogenic cysts were classified as small or large according to maxillary sinus extension within or beyond the alveolar recess, respectively.

RESULTS

A total of 30 patients with odontogenic cysts involving the maxillary sinus were treated by a team of maxillofacial and endoscopic sinus surgeons during the study period. There were 11 cases of dentigerous cysts, 11 radicular cysts, seven odontogenic keratocysts (OKCs), and one glandular cyst. Sixteen cases were managed by transnasal endoscopic sinus surgery alone and 14 were managed by a combined intraoral and endoscopic sinus surgery approach. A total of 22 patients had large cysts and total resection was achieved in 20 of them. There was one case of OKC recurrence during an average follow-up of 31 months. No major complications were recorded.

CONCLUSIONS

The endoscopic approach can serve as an alternative to the transalveolar or lateral window approach. The endoscopic approach is associated with low morbidity and low recurrence rates.

Medication-related osteonecrosis of the jaws associated with intravitreal administration of ranibizumab

Medication-related osteonecrosis of the jaws (MRONJ) is a well-known complication that, in the majority of cases, is related to antiresorptive agents. Numerous articles have described cases of MRONJ in bisphosphonate-naïve patients treated with anti-angiogenic agents administered via various routes. A single case of MRONJ after intravitreal injection of bevacizumab has been reported. We report a case of MRONJ after intravitreal injection of a different anti-angiogenic agent - ranibizumab - for the treatment of neovascular age-related macular degeneration, in a bisphosphonate-naïve patient. Although it may be a rare complication, patients treated with multiple doses of anti-angiogenic agents should be monitored for the possible early diagnosis of MRONJ.

Questioning the Justification of Frontal Sinusotomy for Odontogenic Sinusitis

PURPOSE

Odontogenic sinusitis (OS) can be caused by infectious conditions of the posterior maxillary teeth. The maxillary sinus has been most often involved because of its proximity to the posterior maxillary teeth. Often the anterior ethmoids and frontal sinuses will be involved by the infective process. The underlying odontogenic condition must be addressed before or during sinus surgery. The role of frontal sinusotomy in the treatment of these patients has been poorly described. Our objective was to present the surgical outcomes of patients with OS involving the frontal sinus who had undergone middle meatal antrostomy alone.

PATIENTS AND METHODS

A prospective analysis of all patients who had undergone surgery at a single tertiary center to treat OS involving the frontal sinus from November 2015 to December 2018 was performed. Their preoperative assessment findings, surgical findings, and postoperative outcomes were analyzed.

RESULTS

A total of 45 patients (23 men and 22 women), with a median age of 57 years (range, 20 to 83 years), were enrolled in the present study. All anterior sinuses (frontal, anterior ethmoids, and maxillary sinuses) were clinically and radiographically involved in all the patients. Each patient underwent endoscopic wide maxillary middle meatal antrostomy concurrent with dental intervention. The average follow-up was 7 months. No signs of active frontal disease were detected by postoperative endoscopy in any patient, and no patient required revision surgery.

CONCLUSIONS

The results from the present study have shown that no justification exists for frontal sinusotomy for the treatment of OS involving the frontal sinus. Frontal sinusitis is a secondary infectious and inflammatory process that will resolve once the underlying odontogenic condition has healed and wide middle meatal antrostomy has been performed.