Accounting for pharmacokinetic differences in dual-tracer receptor density imaging

Dual-tracer molecular imaging is a powerful approach to quantify receptor expression in a wide range of tissues by using an untargeted tracer to account for any nonspecific uptake of a molecular-targeted tracer. This approach has previously required the pharmacokinetics of the receptor-targeted and untargeted tracers to be identical, requiring careful selection of an ideal untargeted tracer for any given targeted tracer. In this study, methodology capable of correcting for tracer differences in arterial input functions, as well as binding-independent delivery and retention, is derived and evaluated in a mouse U251 glioma xenograft model using an Affibody tracer targeted to epidermal growth factor receptor (EGFR), a cell membrane receptor overexpressed in many cancers. Simulations demonstrated that blood, and to a lesser extent vascular-permeability, pharmacokinetic differences between targeted and untargeted tracers could be quantified by deconvolving the uptakes of the two tracers in a region of interest devoid of targeted tracer binding, and therefore corrected for, by convolving the uptake of the untargeted tracer in all regions of interest by the product of the deconvolution. Using fluorescently labeled, EGFR-targeted and untargeted Affibodies (known to have different blood clearance rates), the average tumor concentration of EGFR in four mice was estimated using dual-tracer kinetic modeling to be 3.9 ± 2.4 nM compared to an expected concentration of 2.0 ± 0.4 nM. However, with deconvolution correction a more equivalent EGFR concentration of 2.0 ± 0.4 nM was measured.

[Spatiotemporal distribution of tuberculosis cases in the city of Saint-Louis Senegal from 2008-2011]

BACKGROUND

We studied the incidence of tuberculosis in the health district of Saint-Louis, Senegal over a period of 4years (2008-2011). One thousand three hundred and eighty-six cases were identified, producing an annual standardized incidence ratio of 129 cases per 100,000 inhabitants.

RESULTS

Men in the 15-24-year old age group were more likely to be affected, and diagnosis was more common in the second half of the year. Treatment compliance was excellent (96%), and the cure rate of patients with a TB-positive microscopic examination was 95%. The overall treatment failure rate was 1% and the 6-month morality was 2%. Seropositivity, measured in volunteer patients (48%) was 3%.

CONCLUSION

A spatial and temporal map of tuberculosis in the city of Saint-Louis, Senegal has been established. A cluster appears to be very likely in Guet Ndar, a particularly dense population zone in a fishing area. There is also a possible secondary cluster at Pikine.

Kinetic model optimization for characterizing tumour physiology by dynamic contrast-enhanced near-infrared spectroscopy

Dynamic contrast-enhanced (DCE) methods are widely used with magnetic resonance imaging and computed tomography to assess the vascular characteristics of tumours since these properties can affect the response to radiotherapy and chemotherapy. In contrast, there have been far fewer studies using optical-based applications despite the advantages of low cost and safety. This study investigated an appropriate kinetic model for optical applications to characterize tumour haemodynamics (blood flow, F, blood volume, V(b), and vascular heterogeneity) and vascular leakage (permeability surface-area product, PS). DCE data were acquired with two dyes, indocyanine green (ICG) and 800 CW carboxylate (IRD(cbx)), from a human colon tumour xenograph model in rats. Due to the smaller molecular weight of IRD(cbx) (1166 Da) compared to albumin-bound ICG (67 kDa), PS of IRD(cbx) was significantly larger; however, no significant differences in F and V(b) were found between the dyes as expected. Error analysis demonstrated that all parameters could be estimated with an uncertainty less than 5% due to the high temporal resolution and signal-to-noise ratio of the optical measurements. The next step is to adapt this approach to optical imaging to generate haemodynamics and permeability maps, which should enhance the clinical interest in optics for treatment monitoring.

[Thrombocytopenia purpura, myositis and cytolitic hepatitis: a rare association linked with atorvastatin]

Statins are generally well tolerated molecules. However, some cases have seen potentially lifethreatening consequences. We report a case of a 70-year-old woman with high blood pressure who was treating hypercholesterolemia by atorvastatin. Two weeks after beginning this new treatment, the patient developed muscular weakness in all four limbs with myalgias; and a purpura in the upper limbs and abdomen. A biological study revealed the presence of severe thrombocytopenia, myolysis and cytolytic hepatitis. Stopping the atorvastatin intake resulted in an improved situation within twenty days. This suggests that the medical anomalies found in the patient were drug-induced. The literature confirms the rarity of this association. The severity of some side effects of statins should remain in the minds of medicine prescribers.

[Unusual aspect of pernicious anemia during association of beta-thalassemia: a new case report and literature review]

Pernicious anemia appears classically by macrocytosis. We report a case of a late discovered Biermer disease, on a 42-year-old young black woman. The reason was an unusual aspect of this disease in a context of betathalassemia. The patient presented chronic anemia which evolved during about ten year. Biology showed a normocytosis and signs of hemolysis according to beta-thalassemia. This was confirmed by an electrophoresis showing 9.1 % of fraction F some haemoglobin. Since this date, the patient was treated by folic acid alone with periodic transfusions of red blood cell. She presented eight years after the beginning of her disease, neurological deterioration. Diagnosis of pernicious anemia was finally established up on histological gastritis, low level of the blood rate of vitamin B12, macrocytosis, and presence of intrinsic anti-factor and parietal anti-cells antibodies.

[Prevalence of child and teenage obesity in schools in Dakar]

Obesity is currently viewed as a serious worldwide public health issue. In this survey, we aim to determine its prevalence among schoolchildren and teenagers in Dakar. The sample of our survey consisted of 2,356 students aged 11-17, including 1,110 boys and 1,246 girls. For each of them, we have calculated their body mass index. Based on the higher value of the norm of that index, referred to the 97th percentile of Rolland-Cachera MF's curves, we have identified obese students according to their age and sex. The prevalence of obesity within our sample is 9.34%, with 2.88% for boys and 6.46% for girls. It is at its peak in the age of 11, though there is no significance (p > 0.05) in its decrease (from age 12 to 17). There are significantly (p < 0.05) more obese students in "catholic private" schools than in "public" schools where schooling is free. Child and teenage obesity is a reality in Dakar schools. Consequently, it is advisable to determine its nationwide prevalence to take on its prevention as well as its cure.

[The left gastroepiploic artery: a splenic origin but a variable birthplace]

The left gastroepiploic artery (LGEA) is rarely described. The aim of this study is to report the fashion of its origin considering the greatly surgical interest of the short gastric vessels in the spleen-preserving distal pancreatectomy with excision of splenic pedicle. About 79 fresh cadaveric pieces we dissect and opacified the LGEA to specify its origin based on the Pinus's classification. We measured the distances between the origin of the LGEA and the terminal division of the splenic artery, the splenic hilus and the great gastric curvature. The LGEA arise from the splenic artery. Dissection underlines a troncular origin (type I) in 20.25% of cases, a distal origin from an inferior polar branch (type II) in 68.35% of cases and an origin from a common spleno-gastroepiploic trunk (type III) in 11.4% of cases. The three distances measured was respectively of 28.7, 25.3 and 31.4mm. The arteriography revealed respectively for the same types 21.21, 51.51 and 27.28%. The vascular disposition of the type III well illustrates the important role of the LGEA for the vascularization of the inferior pole of the spleen. Although the LGEA arise from a polar splenic lower branch in more half of the cases, it is important to know the frequency of the other modalities of its origin. These anatomical variations vascular are to be considered during spleen-preserving distal pancreatectomy with excision of splenic pedicle as well as for gastric esophagoplasty.

[Perforation and haemorrhage duodenal bulbar ulcers in a child: a case report]

A perforation rarely reveals a primary duodenal ulcer. The occurring of digestive haemorrhage in post operative followings evokes spontaneously a stress ulcer. We report an observation of a child who presented on fourth day delay after operation an ulcer of the anterior duodenal bulbar face and a haemorrhage of the posterior bulbar face. A 7-year-old girl with no particular pathological antecedent was admitted for abdominal pain, bile vomiting and constipation evolving since 6 days. Clinical examination revealed a general state thickening, an infectious syndrome, a meteoric and general abdominal sensitivity. The abdominal radiography without preparation showed a pneumoperitoneum. The surgical exploration discovered a perforated ulcer on the bulbar anterior face. A simple closure associated with omental patch was performed. Four days after operation, she presented an abundant digestive haemorrhage with shock. The resuscitation did not improve the patient's general state. The upper digestive endoscopy revealed a haemorrhage of the posterior bulbar face. An adrenalin injection stopped the bleeding. The treatment by neutron pump inhibitors and an eradicating treatment of Helicobacter pylori permitted the healing of the ulcers. The occurring of digestive haemorrhage in the followings of surgical intervention for perforated ulcer involves an upper digestive endoscopy. This examination can reveal misdiagnosed ulcer during the surgical exploration and permits to perform a haemostatic act.

Anatomical basis of neuropathies and damage to the ilioinguinal nerve during repairs of groin hernias. (about 100 dissections)

Surgical access to the inguinal region, notably during hernia repairs, exposes the ilioinguinal nerve to the risk of damage at the origin of the neuralgia. The incidence of these post-operative neuropathies and their medicolegal consequences justify this study about the anatomical variations of the ilioinguinal nerve. With the aim of preventing its damage during repairs of groin hernias and identifying the factors of onset of chronic spontaneous neuropathy of the ilioinguinal nerve, we dissected 100 inguinal regions of 51 fresh adult corpses. The nerve was absent in seven cases and double in one case. Out of the 94 ilioinguinal nerves observed, we analyzed the path in relation to the inguinal ligament and the connections with the walls of the inguinal canal and its content. The ilioinguinal nerve travels along the superficial surface of the internal oblique muscle, passing on average 1.015 cm from the inguinal ligament. In one case, the fibers of the internal oblique muscle spanned it in several places. The nerve was antero-funicular in 78.72% of cases and perforated the fascia of the external oblique in 28.72% of cases. The terminal division took place in the inguinal canal in 86% of cases, with terminal branches that sometimes perforated the fascia of the external oblique. These results enabled us to better understand the etiopathogenic aspects of certain neuropathies of the groin and to propose techniques useful for the protection of the nerve during repairs of groin hernias.

[Anastomotic method of the gastro-omental arterial circle: interest in the transillumination method at the gastric esophagoplasty]

The gastroomental (gastroepiploic) arterial circle of the stomach is the main vascular axis of the gastroplasty use as esophagus substitute after esophagectomy. The aim of this anatomoangiographic study is to study the anastomosis between the right and left gastroomental arteries and emphasize interest of the transillumination: an ordinary anatomic method use in surgical practice. We use forty five fresh cadaveric stomach of adult for determine the anastomotic fashion of the arterial circle of the great gastric curvature. About three models of gastric esophagoplasty we verify similarity of vascular transillumination results and we compare with the radiographic exploration. The thickness of the gastrocolic ligament in which progress the gastroomental arterial circle can lead astray for macroscopic determination of anastomotic mode. Thus the type I, II, III and IV which are of 60%, 22,2%, 13,3% and 4,4% at macroscopic observation become 64,1%, 15,4%, 15,4% and 5,1% after arteriographic analysis. Even if the submucosal arteriolar network and the rich parietal anastomosis confer at the stomach the best qualities for esophageal replacement, the multifactorial particularity of success in esophagogastroplasty require identification and preservation of the gastroomental arterial circle. The transillumination which facilitate evaluation of this arterial axis is a simple and accessible process which we advocate.

The arch of the great saphenous vein: anatomical bases for failures and recurrences after surgical treatment of varices in the pelvic limb. About 54 dissections

The arch of the great saphenous vein presents numerous tributaries. Misappreciation of their anatomical variations might cause recurrence after surgical treatment of varices. We dissected 54 inguino-femoral regions of fresh, black African corpses. Our purpose was to study the anatomical variations in the vein confluents of the arch of the great saphenous vein; its positions in relation to the external pudendal artery; establish palpable anatomical markers for its surgical approach. The conventional type in a 'vein star' shape was not the most frequent. Upper or abdominal common vein produced through the merging of superficial veins of the anterior abdominal wall and genital or internal common vein were more frequent. An anterior saphenous vein was found in 23 cases. The external pudendal artery crossed beneath the arch of the great saphenous vein cross in 56% of cases and previously in 44% of cases. On average, the top of the arch of the great saphenous vein was projected out 10.88 cm from the ventral and cranial iliac spine, 3.83 cm from the pubic tubercle and 4.19 cm from the inguinal ligament. In view of our results, variations are real. Knowing and taking them into account are essential to prevent recurrences after surgical treatment of varices of the pelvic limb.

Influence of Speed Variation and Age on Ground Reaction Forces and Stride Parameters of Children's Normal Gait

The aim of this study was to assess the influence of both age and speed on ground reaction forces and temporal parameters during normal gait in children. Fifteen children aged 4-6 years (group 1), 16 aged 6-8 years (group 2), and 16 aged 8-10 years (group 3) walked at 2.7 km/h, 3.6 km/h, and 4.5 km/h on a treadmill. For each child thirty successive steps were recorded. The influence of speed and age on normalized gait parameters was examined with two-way analysis of variance. The first vertical peak force (Fz1) and all the antero-posterior forces of group 1 were higher than those of the other groups for the three speeds. The minimum vertical force (Fz2), the second vertical peak force (Fz3), and the duration of stride and stance were significantly higher in groups 2 and 3. For all the groups, Fz1 and all the antero-posterior forces increased with the speed while Fz2, stride, stance, and double-stance duration decreased. Fz3 was not influenced by speed variation. The results of this study show that age and walking speed influence ground reaction forces and stride time parameters in 4- to 10-year-old children.

Evaluation of novel diagnostic tools for peste des petits ruminants virus in naturally infected goat herds

A survey was carried out in two goat herds during a single peste des petits ruminant (PPR) outbreak. Clinical examination showed that animals belonging to the West African Dwarf species had severe symptoms while those belonging to the West African long-legged species had mild symptoms. To confirm and to monitor the disease in each species, the study required specific monoclonal antibody-based diagnostic tools. An association of shedding of PPR virus (PPRV) and acute or mild clinical signs of the disease could be demonstrated by the rinderpest virus (RPV)/PPRV immunocapture ELISA assay. Between 85 and 100% of nasal secretions obtained from clinically diseased goats during the PPR outbreak reacted positively. Parallel serological surveillance for specific measurement of PPR antibodies revealed that between 34.4 and 88.5% of animals with no detectable virus were, however, able to seroconvert and therefore seemed to demonstrate that PPR subclinical infections do occur. Antibodies were shown to impair the RP heterologous vaccination. This evaluation offers new prospects for diagnosis and management of PPRV infection as well as for RPV control.

[Cadaveric topography and morphometry of the vermiform appendix]

Our study justified by the frequency of acute appendicitis and the possibility of anatomic variations of the caecoappendicular area attempt to index the topographic variations of the vermiform appendix (v.a.). On 80 fresh native cadavers (62 men and 18 women) without surgical antecedent whose mean age was 36 years (range between 16 and 78 years) we note the morphotype and the height. More over we study the intraperitoneal projection of the Mac Burney point, topography and shape of the cecum and the situation, shape and dimensions of the v.a. We note also the level of implantation of this latter on the cecum, appearance of the mesoappendix and the distance separating the base of the appendix to the ileo-caecal junction. Mac Burney's point permitted to localize appendix in 66%; the cecum has more often than not the form of a bulb (98.7%) and sited in right fossa iliaca. We noted 7 types of topographic disposition; front varieties were more frequent (68.7%) notably the pelvic direction (51.2%) with a medial (72.5%) or a posteromedial (27.5%) establishment on the cecum. The v.a. was more often in the form of worm with a long mesoappendix; his mean length was 106.4 mm (between 65 and 160 mm) and the mean diameter 6.77 mm (range between 4 and 10 mm). The distance which separated the base of the appendix to the ileo-cecal junction varied between 15 to 40 mm with a mean distance of 24.2 mm. Thus in this study, dimensions of the v.a. were very variables. Located in right fossa iliaca he adopted a front topography with pelvic direction and medial establishment on bulbar cecum. In spite of scarcity of ectopic situation of the appendix for which laparoscopic approach is salutary, a similar topographic study during surgical treatment of acute appendicitis will be interesting.