APSIM-based modeling approach to understand sorghum production environments in Mali.

Sorghum production system in the semi-arid region of Africa is characterized by low yields which are generally attributed to high rainfall variability, poor soil fertility, and biotic factors. Production constraints must be well understood and quantified to design effective sorghum-system improvements. This study uses the state-of-the-art in silico methods and focuses on characterizing the sorghum production regions in Mali for drought occurrence and its effects on sorghum productivity. For this purpose, we adapted the APSIM-sorghum module to reproduce two cultivated photoperiod-sensitive sorghum types across a latitude of major sorghum production regions in Western Africa. We used the simulation outputs to characterize drought stress scenarios. We identified three main drought scenarios: (i) no-stress; (ii) early pre-flowering drought stress; and (iii) drought stress onset around flowering. The frequency of drought stress scenarios experienced by the two sorghum types across rainfall zones and soil types differed. As expected, the early pre-flowering and flowering drought stress occurred more frequently in isohyets < 600 mm, for the photoperiod-sensitive, late-flowering sorghum type. In isohyets above 600 mm, the frequency of drought stress was very low for both cultivars. We quantified the consequences of these drought scenarios on grain and biomass productivity. The yields of the highly-photoperiod-sensitive sorghum type were quite stable across the higher rainfall zones > 600 mm, but was affected by the drought stress in the lower rainfall zones < 600 mm. Comparatively, the less photoperiod-sensitive cultivar had notable yield gain in the driest regions < 600 mm. The results suggest that, at least for the tested crop types, drought stress might not be the major constraint to sorghum production in isohyets > 600 mm. The findings from this study provide the entry point for further quantitative testing of the Genotype × Environment × Management options required to optimize sorghum production in Mali. Supplementary Information: The online version contains supplementary material available at 10.1007/s13593-023-00909-5.

Impact of preoperative radiotherapy on head and neck free flap reconstruction: a report on 429 cases.

BACKGROUND: The primary objective of this study was to evaluate the impact of preoperative radiotherapy on the outcomes of head and neck microvascular reconstruction. The secondary objective was to assess the specific effects of irradiation doses (IDs) ≥60 Gy on the outcomes of head and neck microvascular reconstruction. METHODS: All patients who underwent head and neck free-flap reconstruction in our institution between 2000 and 2010 were included in this retrospective study. A total of 429 patients were enrolled including 136 patients previously irradiated on the head and neck. The impact of preoperative radiotherapy on free-flap success, local and general complications, postoperative mortality, time of decannulation, duration of enteral nutrition and length of stay was assessed in univariate and multivariate analyses. RESULTS: In multivariate analysis, preoperative radiotherapy (irrespective of ID) was a significant risk factor for fistula formation (p = 0.003) and wound infection (p = 0.005). Previous neck irradiation at doses ≥60 Gy was associated with an increased risk of free-flap failure (p = 0.04), overall local complications (p = 0.05), haematoma (p = 0.04) and longer duration of enteral nutrition (p = 0.006) and hospital stay (p = 0.004). CONCLUSIONS: Preoperative radiotherapy, particularly for ID ≥ 60 Gy, is one of the main determinants of the outcomes of head and neck microvascular reconstruction.

Clinical and histological prognostic factors in locally advanced oral cavity cancers treated with primary surgery.

OBJECTIVE: The primary objective of this study was to determine the clinical and pathological prognostic factors in locally advanced oral cavity cancers treated by primary surgery. METHODS: All patients treated by primary surgery with free-flap reconstruction for locally advanced oral cavity squamous cell carcinoma in our institution between 2000 and 2010 were included in this retrospective study. Overall, cause-specific and locoregional disease-free survivals were determined by Kaplan-Meier analyses. Clinical and histological prognostic factors were assessed by univariate (Log Rank tests) and multivariate (Cox models) analyses. RESULTS: A total of 149 patients (102 men and 47 women; mean age=61.3±12.1 years) were included in the study. Five-year overall, cause-specific and locoregional disease-free survivals were 55%, 68% and 71%, respectively. Age, comorbidity and tumour size (histological evaluation) were significantly correlated with overall survival (P<0.05). Age, tumour size, bone invasion and surgical margins were significantly correlated with locoregional disease-free survival (P<0.05). CONCLUSION: The main prognostic factors identified in this study were clinical (age and comorbidity) and histological (pathological tumour size, bone invasion and surgical margins).

Laryngeal chondrosarcoma: report of two cases.

OBJECTIVE: The present study describes the clinical, radiological and histological features of laryngeal chondrosarcoma, on the basis of two clinical cases, and discusses management. CASE STUDIES: Two male patients, aged 63 and 51 years, presented with low-grade chondrosarcoma revealed respectively by a mass in the lateral neck and by laryngeal dyspnea. CT showed a tumoral process with calcification, developed from the thyroid and cricoid cartilage, respectively. The first patient underwent partial and the second total laryngectomy. DISCUSSION: Chondrosarcoma is diagnosed on the basis of combined clinical, radiological and histological signs. Differential diagnosis with chondroma may be difficult, especially in grade-1 chondrosarcoma. CONCLUSION: Laryngeal chondrosarcoma is a rare tumor. Management is basically surgical. Prognosis is generally good, depending essentially on histologic grade.

Head and neck free-flap reconstruction in the elderly.

OBJECTIVE: To evaluate the reliability of free-flap head and neck reconstruction in the elderly. MATERIAL AND METHODS: All patients who underwent free-flap head and neck reconstruction in our institution between 2000 and 2010 were included in this retrospective study. In all, 418 patients (301 men and 117 women) were enrolled, including 95 patients aged 70 years or older (mean age=60.2±11.6 years). The impact of age on free-flap failure and local and general complication rates was assessed on univariate and multivariate analysis. RESULTS: Advanced age had no impact on free-flap failure and local complications rate but was correlated with a higher risk of general complications (multivariate analysis: P=0.007). A high level of comorbidity also had a significant impact on the general complications rate (multivariate analysis: P=0.001). Patients who underwent circular total pharyngolaryngectomy showed elevated risk of free-flap failure (P=0.005) and local complications (P=0.001) on multivariate analysis. CONCLUSION: Free-flap reconstruction of the head and neck is safe and reliable in the elderly. Nevertheless, meticulous patient selection, mainly based on the level of comorbidity, is necessary.

[Total pharyngolaryngectomy in the 21st century: indications, oncologic and functional outcomes]. / Les pharyngo-laryngectomies totales au 21ème siècle : indications, résultats carcinologiques et fonctionnels.

INTRODUCTION: The development of laryngeal preservation protocols has considerably modified the indications for total (pharyngo-)laryngectomy (TPL). The objectives of our study are to analyze the current indications for TPL and to evaluate the oncologic and functional outcomes after TPL and their predictive factors. METHODS: All patients who underwent TPL for squamous cell carcinoma of the larynx or hypopharynx, at our institution, between 2000 and 2009, were included in this retrospective study. Predictive factors of oncologic and functional outcomes were assessed in univariate and multivariate analyzes. RESULTS: A total of 130 patients were enrolled in our study including 119 men and 11 women, with a mean age of 65.9 years. TPL was realized for salvage in 65 patients. Extra-laryngeal tumor extension (n = 42) was the main indication for TPL in the 65 remaining patients. Overall survival was 49 and 41% at 3 and 5 years respectively. In multivariate analysis, primary tumor site (hypopharynx in comparison to larynx; p = 0.04) has a significant pejorative impact on overall survival. Oral alimentation (no enteral nutrition) was recovered successfully by 94% of the patients. In multivariate analysis, primary tumor site (hypopharynx) has a significant pejorative impact on functional results (deglutition: p < 0.0001; phonation: p = 0.03). CONCLUSION: Primary tumor site is one of the main predictive factor of oncologic and functional outcomes after TPL.

Structural and functional characterization of H protein mutants of the glycine decarboxylase complex.

The mitochondrial glycine decarboxylase complex (GDC) consists of four component enzymes (P, H, T, and L proteins) involved in the breakdown of glycine. In order to investigate structural interactions involved in the stabilization of the methylamine-loaded H protein (a transient species in the GDC reaction), we designed several mutants of H apoprotein. Structural analysis of the wild-type and mutants of H apoprotein emphasized the necessity to carefully assess, by biophysical techniques, the correct folding of mutated proteins prior to investigate their biochemical properties. The correctly folded wild-type and mutants of H apoprotein were in vitro lipoylated and then characterized in the context of GDC reaction by studying the reconstituted complex and partial reactions. We showed that Val(62) and Ala(64), surrounding the lipoyl-lysine, play an important role in the molecular events that govern the reaction between P and H protein but do not intervene in the recognition of the binding site of lipoic acid by lipoyl ligase. The biochemical results obtained with the HE14A mutant of H protein pointed out the major role of the Glu(14) amino acid residue in the GDC catalysis and highlighted the importance of the ionic and hydrogen bounds in the hydrophobic cleft of H protein for the stabilization of the methylamine-loaded lipoyl arm.