Genetic algorithm with cross-validation-based epidemic model and application to the early diffusion of COVID-19 in Algeria

A dynamical epidemic model optimized using a genetic algorithm and a cross-validation method to overcome the overfitting problem is proposed. The cross-validation procedure is applied so that available data are split into a training subset used to fit the algorithm's parameters, and a smaller subset used for validation. This process is tested on Italy, Spain, Germany, and South Korea cases before being applied to Algeria. Interestingly, our study reveals an inverse relationship between the size of the training sample and the number of generations required in the genetic algorithm. Moreover, the enhanced compartmental model presented in this work has proven to be a reliable tool to estimate key epidemic parameters and the non-measurable asymptomatic infected portion of the susceptible population to establish a realistic nowcast and forecast of the epidemic's evolution. The model is employed to study the COVID-19 outbreak dynamics in Algeria between February 25th, 2020, and May 24th, 2020. The basic reproduction number and effective reproduction number on May 24th, after three months of the outbreak, are estimated to be 3.78 (95% CI 3.033-4.53) and 0.651 (95% CI 0.539-0.761), respectively. Disease incidence, CFR, and IFR are also calculated. Numerical programs developed for this study are made publicly accessible for reproduction and further use.

Generation and characterization of dromedary Tenascin-C and Tenascin-W specific antibodies

Tenascin-C (TNC) and tenascin-W (TNW), large hexameric glycoproteins overexpressed in the tumor microenvironment, are useful tumor biomarkers for theranostic applications. For now, polyclonal and monoclonal antibodies, as well as aptamers targeting TNC and TNW have been developed. However, the immunostaining sensitivity of antibodies is very heterogenous. The main aim of this study was to generate antibodies in dromedary that detect TNC and TNW, respectively. We show that immune sera from immunized dromedaries are able to specifically bind native TNC and TNW by ELISA and also to detect TNC and TNW in matrix tracks of mammary tumors by immunostaining. Furthermore, we demonstrate that purified IgG subtypes are able to interact specifically with TNC or TNW by ELISA and immunostaining. These camelid antibodies are a good basis to develop tools for the detection of TNC and TNW in the tumor microenvironment and could potentially have a broader application for early diagnosis of solid cancers.

[Interests and limitations of percutaneous coronary intervention strategy in nonagenarian patients: A single center experience]

AIM

To expose our center results in the angioplasty in nonagenarians and to evaluate its effectiveness but also the MACEs and the mortality in the short and long term.

METHODS

A retrospective study of 98 patients admitted to the Antibes hospital center from November 2013 to September 2018.

RESULTS

The median age was 91.8 [90.8-93.4]. 52.6% was male. 9.7% of the patients had a polyvascular site. 50.6% of patients had moderate renal failure. The radial approach was used in 88.4% of cases. 21.6% of patients had tri-truncal lesions, while 46.4% were monotruncular, LAD artery was the culprit artery in 67% of cases. One stent per lesion was used in the majority of cases. Our successful rate was 90%. After angioplasty, 96% of the patients underwent double antiaggregation platelet therapy, 74.4% under clopidogrel. The presence of arrhythmias before angioplasty, the femoral approach, the coronary dissection and cardiogenic shock after angioplasty were predictors of short- and long-term mortality. Diabetes, history of myocardial infarction, impaired left ventricular ejection fraction, calcified coronary lesions, occurrence of arrhythmias or signs of heart failure on post-procedure were predictors of MACE occurrence.

CONCLUSIONS

This study demonstrates that angioplasty in selected population of nonagenarians is perfectly feasible with a good risk/benefit ratio and specifies the different predictors of MACE, both short- and long-term mortality.

Stromal fibroblasts present in breast carcinomas promote tumor growth and angiogenesis through adrenomedullin secretion

Tumor- or cancer-associated fibroblasts (TAFs or CAFs) are active players in tumorigenesis and exhibit distinct angiogenic and tumorigenic properties. Adrenomedullin (AM), a multifunctional peptide plays an important role in angiogenesis and tumor growth through its receptors calcitonin receptor-like receptor/receptor activity modifying protein-2 and -3 (CLR/RAMP2 and CLR/RAMP3). We show that AM and AM receptors mRNAs are highly expressed in CAFs prepared from invasive breast carcinoma when compared to normal fibroblasts. Immunostaining demonstrates the presence of immunoreactive AM and AM receptors in the CAFs (n = 9). The proliferation of CAFs is decreased by anti-AM antibody (αAM) and anti-AM receptors antibody (αAMR) treatment, suggesting that AM may function as a potent autocrine/paracrine growth factor. Systemic administration of αAMR reduced neovascularization of in vivo Matrigel plugs containing CAFs as demonstrated by reduced numbers of the vessel structures, suggesting that AM is one of the CAFs-derived factors responsible for endothelial cell-like and pericytes recruitment to built a neovascularization. We show that MCF-7 admixed with CAFs generated tumors of greater volume significantly different from the MCF-7 xenografts in nude mice due in part to the induced angiogenesis. αAMR and AM_22-52 therapies significantly suppressed the growth of CAFs/MCF-7 tumors. Histological examination of tumors treated with AM_22-52 and aAMR showed evidence of disruption of tumor vasculature with depletion of vascular endothelial cells, induced apoptosis and decrease of tumor cell proliferation. Our findings highlight the importance of CAFs-derived AM pathway in growth of breast carcinoma and in neovascularization by supplying and amplifying signals that are essential for pathologic angiogenesis.

Functional Analysis of the Adrenomedullin Pathway in Malignant Pleural Mesothelioma

INTRODUCTION

Malignant pleural mesothelioma (MPM) grows aggressively within the thoracic cavity and has a very low cure rate, thus highlighting the need for identification of new therapeutic targets. Adrenomedullin (AM) is a multifunctional peptide that is highly expressed in several tumors and plays an important role in angiogenesis and tumor growth after binding to its receptors, calcitonin receptor-like receptor/receptor activity-modifying protein 2 (CLR/RAMP2) and calcitonin receptor-like receptor/receptor activity-modifying protein 3 (CLR/RAMP3).

METHODS

Real time quantitative reverse transcriptase polymerase chain reaction (RT-PCR) was used to assess the steady-state levels of AM, CLR, RAMP2 and RAMP3 messenger RNA (mRNA) transcripts in normal pleural tissue (n=5) and MPM (n=24). The expression of these candidates at protein level was revealed by immunohistochemistry. We also characterized the expression and regulation by hypoxia of AM system in MPM cell lines and MeT-5A cells. In vitro and in vivo studies were performed to determine the functional role of AM system in MPM.

RESULTS

In this study, real-time quantitative reverse transcriptase polymerase chain reaction showed twofold to 10-fold higher levels of AM messenger RNA in MPM tissue than in normal pleural tissue. The MPM cell lines H2452, H2052, and human mesothelioma cell line MSTO-211H showed a significant increase in expression of AM messenger RNA under hypoxic conditions. Our results also show that AM stimulates cell proliferation in vitro through the Raf1 proto-oncogene, serine/threonine kinase (CRAF)/ Mitogen-activated protein kinase kinase 1 (MEK)/Extracellular regulated MAPKinase (ERK) pathway. Furthermore, the proliferation, migration, and invasion of MPM cells were decreased after treatment with anti-AM (αAM) and anti-AM receptor antibodies, thus indicating that MPM cells are regulated by AM. The action of AM was specific and mediated by CLR/RAMP2 and CLR/RAMP3 receptors. In vivo, αAM and AM22-52 antagonist therapies blocked angiogenesis and induced apoptosis in MSTO-211H xenografts, thereby resulting in tumor regression. Histologic examination of tumors treated with AM22-52 and αAM antibody showed evidence of disruption of tumor vasculature with depletion of vascular endothelial cells and a significant decrease in lymphatic endothelial cells.

CONCLUSIONS

Our findings highlight the importance of the AM pathway in growth of MPM and in neovascularization by supplying and amplifying signals that are essential for pathologic neoangiogenesis and lymphangiogenesis.

Adrenomedullin blockade suppresses growth of human hormone-independent prostate tumor xenograft in mice

PURPOSE

To study the role of the adrenomedullin system [adrenomedullin and its receptors (AMR), CLR, RAMP2, and RAMP3] in prostate cancer androgen-independent growth.

EXPERIMENTAL DESIGN

Androgen-dependent and -independent prostate cancer models were used to investigate the role and mechanisms of adrenomedullin in prostate cancer hormone-independent growth and tumor-associated angiogenesis and lymphangiogenesis.

RESULTS

Adrenomedullin and AMR were immunohistochemically localized in the carcinomatous epithelial compartment of prostate cancer specimens of high grade (Gleason score >7), suggesting a role of the adrenomedullin system in prostate cancer growth. We used the androgen-independent Du145 cells, for which we demonstrate that adrenomedullin stimulated cell proliferation in vitro through the cAMP/CRAF/MEK/ERK pathway. The proliferation of Du145 and PC3 cells is decreased by anti-adrenomedullin antibody (αAM), supporting the fact that adrenomedullin may function as a potent autocrine/paracrine growth factor for prostate cancer androgen-independent cells. In vivo, αAM therapy inhibits the growth of Du145 androgen-independent xenografts and interestingly of LNCaP androgen-dependent xenografts only in castrated animals, suggesting strongly that adrenomedullin might play an important role in tumor regrowth following androgen ablation. Histologic examination of αAM-treated tumors showed evidence of disruption of tumor vascularity, with depletion of vascular as well as lymphatic endothelial cells and pericytes, and increased lymphatic endothelial cell apoptosis. Importantly, αAM potently blocks tumor-associated lymphangiogenesis, but does not affect established vasculature and lymphatic vessels in normal adult mice.

CONCLUSIONS

We conclude that expression of adrenomedullin upon androgen ablation in prostate cancer plays an important role in hormone-independent tumor growth and in neovascularization by supplying/amplifying signals essential for pathologic neoangiogenesis and lymphangiogenesis. Clin Cancer Res; 19(22); 6138-50. ©2013 AACR.

The cactus effect: an alternative to the lupin effect for increasing ovulation rate in sheep reared in semi-arid regions?

The present study evaluated the effects of supplementation with cactus cladodes on follicular dynamics and ovulatory response of sheep reared in semi-arid areas. A total of 76 ewes were distributed into two equal groups supplemented with either concentrated feed or cactus cladodes. After 30 days of supplementation, no differences were found between feeding regimens on the final live weight (LW; 41.5 ± 0.6 and 42.1 ± 0.7 kg in the Concentrate and Cactus groups respectively) and body condition score (BCS; 1.8 ± 0.3 and 1.8 ± 0.4 for Concentrate and Cactus group respectively). Moreover, no differences were found between the initial and the final values of both LW and BCS; thus, there were no effects of supplementation on any of both parameters. Analysis of follicular population showed that, during the follicular phase induced by ram effect, the number of follicles reaching ovulatory size increased in both groups. However, the number was always higher in Cactus ewes and, at oestrus, Cactus ewes had 1.6 ± 0.2 and Concentrate sheep had 1.2 ± 0.2 large follicles (p < 0.05). Thereafter, ovulation rate was affected by duration of supplementation; being higher in sheep fed with cactus for 6-10 days (1.7 ± 0.1) than in ewes supplied with cactus for more than 11 days (1.3 ± 0.1; p < 0.05), in sheep fed with concentrate for 6-10 days (1.2 ± 0.1; p < 0.01) and even than in individuals subjected to classical flushing with concentrate (1.3 ± 0.1; p < 0.05).

Scale effect on wave propagation of double-walled carbon nanotubes with initial axial loading

This paper studies the vibrational characteristics of double-walled carbon nanotubes (DWNTs) with initial stress using a nonlocal Euler-Bernoulli beam model. Both the effect of initial stress and the effect of small length scale are discussed in detail. The effect of van der Waals forces is incorporated in the formulation. The corresponding resonant vibrational characteristics are presented in detail; they are shown to be very different from those predicted by classical elasticity theory when nonlocal effects are significant. The influence of initial stress in carbon nanotubes on their flexural vibration modes is dependent on the tension or compression form of the initial stress. The investigation of the effects of initial stress on transverse wave propagation in carbon nanotubes may be used as a useful reference for the application and the design of nanoelectronic and nanodrive devices, nano-oscillators, and nanosensors, in which carbon nanotubes act as basic elements.

Le syndrome de Carney : un nouveau cas

Carney's triad is a very unusual syndrome, associating three different tumours on the same patient, a young woman generally: a gastric leiomyoblastoma, a pulmonary chondroma and an extra-adrenal paraganglioma. The authors report through the literature review and a new case of Carney's syndrome associating gastric leiomyoblastoma and extra-adrenal paragangliomas, the different diagnostic and therapeutic criterias.

[Heller's myotomy without fundoplication: a series of 123 patients]

INTRODUCTION

Surgical treatment of achalasia of lower oesophageal sphincter is Heller's myotomy, usually associated with a fundoplication due to an high risk of postoperative gastro-oesophageal reflux. The value of this fundoplication is discussed. The aim of this study was to evaluate retrospectively the results of Heller's myotomy without fundoplication but performed according to a precise technique preventing postoperative reflux.

PATIENTS AND METHODS

Between 1975 and 1999, 123 patients underwent Heller's myotomy without systematic fundoplication. Diagnosis of achalasia was performed clinically and confirmed by investigations: baryum meal, fibroscopy and manometry. Myotomy was performed through an abdominal approach in 117 (95%) patients. Dissection preserved fixity of abdominal oesophagus in all cases, particularly its posterior meso. Myotomy was performed on abdominal oesophagus but not below the cardia. Posterior fundoplication was associated in 2 patients.

RESULTS

One patient (0,8%) died from massive aspiration. Morbidity (1,6%) consisted in one peritonitis and one postoperative occlusion. At follow-up (mean = 5 years; range: 1-20), functional results were satisfying (excellent and good) in 112 (92%) patients. Seven patients (6%) developed postoperative reflux, including one who need surgical treatment. Dysphagia persisted in 3 patients (2%) who had to be reoperated.

CONCLUSION

Results of this series show that systematic fundoplication is not necessary in Heller's myotomy for achalasia of lower oesophageal sphincter.

[Leiomyoma of the esophagus]

BACKGROUND

Leiomyoma is a benign tumor rarely occurring in the esophagus. Only 1% of esophageal tumors are leiomyomas.

CASE REPORT

A 70-year-old man underwent surgery for an asymptomatic tumor of the thoracic esophagus. The tumor was enucleated via right thoracotomy and histology confirmed the diagnosis of leiomyoma. Outcome was favorable.

DISCUSSION

Leiomyomas of the esophagus generally develop from the muscularis and exceptionally from the muscularis mucosae, producing a parietal tumor or a pediculated endoluminal tumor respectively. Surgery is indicated for all cases, with the possible exception of asymptomatic leiomyoma. Encleation can be achieved by videothoracoscopy. Resection of the esophagus can be discussed if enucleation is impossible for giant tumors, or ring tumors at the esogastric junction, or if the mucosae wound cannot be repaired. Endoscopic resection is indicated for pediculated leiomyoma. Malignant transformation is exceptional but an association between esophageal myomatosis and carcinoma of the esophagus is possible. Certain authors thus advocate resection for all cases, even small asymptomatic leiomyomas.

[Adenocarcinoma of the anal glands]

The study aim was to report an adenocarcinoma of the anal glands revealed by an anal abscess in a 64-year-old man. Malignant transformation of an anal fistula is discussed in the genesis of this disease. Clinical symptoms are not specific. Abdomino-perineal resection of the rectum is the usual surgical treatment and adjuvant radiation therapy didn't prove its efficiency.

[Inflammatory pseudotumor of the spleen]

Inflammatory pseudotumor of the spleen is a very rare benign lesion of unknown etiology. Splenectomy is recommended to obtain histological diagnosis and to eliminate a malignant tumor.

[Place of super-selective vagotomy in the treatment of perforated duodenal ulcer]

Thirty-two duodenal ulcer perforations were treated by suture and supraselective vagotomy. Perioperative mortality was nil. The recurrence rate was 6.2% against 17% after elective supraselective vagotomy performed by the same surgeons during the same period. Results of this technique for treatment of perforated duodenal ulcer are compared with those of 28 simple sutures and 32 truncal vagotomies.

[Reflections on the post-cholecystectomy syndrome]

To look for the explanation about the post-cholecystectomy syndrome, the authors study 637 liver's biopsies during cholecystectomy for cholelithiasis. 373 liver's biopsies showed hepatic lesions (58.5 per cent). The post-cholecystectomy syndrome is observed in 36 per cent of patients who had hepatic lesions, and only 13 per cent of patients with normal liver biopsies.