Predicting the distribution of whey protein fouling in a plate heat exchanger using the kinetic parameters of the thermal denaturation reaction of ß-lactoglobulin and the bulk temperature profiles.

Fouling of plate heat exchangers (PHE) is a severe problem in the dairy industry, notably because the relationship between the build-up of protein fouling deposits and the chemical reactions taking place in the fouling solution has not yet been fully elucidated. Experiments were conducted at pilot scale in a corrugated PHE, and fouling deposits were generated using a model ß-lactoglobulin (ß-LG) fouling solution for which the ß-LG thermal denaturation reaction constants had been previously determined experimentally. Then 18 different bulk temperature profiles within the PHE were imposed. Analysis of the fouling runs shows that the dry deposit mass per channel versus the ratio R=kunf/kagg (with kunf and kagg representing, respectively, the unfolding and aggregation rate constants computed from both the identification of the ß-LG thermal denaturation process and knowledge of the imposed bulk temperature profile into the PHE channel) is able to gather reasonably well the experimental fouling mass data into a unique master curve. This type of representation of the results clearly shows that the heat-induced reactions (unfolding and aggregation) of the various ß-LG molecular species in the bulk fluid are essential to capture the trend of the fouling mass distribution inside a PHE. This investigation also illustrates unambiguously that the release of the unfolded ß-LG (also called ß-LG molten globule) within the bulk fluid (and the absence of its consumption in the form of aggregates) is a key phenomenon that controls the extent of protein fouling as well as its location inside the PHE.

[Management of cardiac arrhythmias during pregnancy]. / La prise en charge thérapeutique des troubles du rythme cardiaque au cours de la grossesse.

INTRODUCTION: Pregnancy can precipitate or exacerbate cardiac arrhythmias. Management of those arrhythmias is not very different from that in non-pregnant women. OBJECTIVE: In this review we tried to specify factors which favour arrhythmias in pregnant women and to show their specific management. METHODS: We carried out a search through PubMed using as keywords: pregnancy, cardiac arrhythmias, antiarrhythmics. RESULTS: Hemodynamic perturbations, direct electrophysiological effects of hormones and underlying heart disease are potential factors that can promote arrhythmias in pregnancy. Usually, no drug therapy is needed for the management of supraventricular or ventricular premature beats but potential promoting factors should be eliminated. In paroxysmal supraventricular tachycardia, vagal maneuvers should be tried firstly. Adenosine could be used if vagal maneuvers are ineffective. In pregnant women with atrial fibrillation, the goal of treatment is the conversion to sinus rhythm or the control of ventricular rate. Ventricular arrhythmias are usually uncommon during pregnancy and often occur in the absence of structural heart disease and are responsive to drug therapy. Symptomatic bradycardia rarely complicates pregnancy and its management does not differ from that in non-pregnant women.

[Central nervous system medulloepithelioma. A report of three cases]. / Le médulloépithéliome du système nerveux central. À propos de trois cas.

Central nervous system medulloepithelioma is a rare, highly malignant childhood tumor. It might be confused with medulloblastoma or other primitive neuroectodermal tumors, but it is quite particular by its clinical, radiological, and pathological features. The mean survival varies depending on whether or not a gross-total resection is possible. Adjuvant radiochemotherapy is often indicated. Only two reported cases in the literature survived beyond 4 years after treatment by gross total resection and radiotherapy without chemotherapy. We report three cases of supratentorial medulloepithelioma occurring in three children aged 11-17 years. Two patients underwent a gross-total resection followed by radiotherapy and survived more than 4 years after treatment. The third case had, however, recurred twice within the 1st postoperative month despite a complete resection each time and metastasis to the lung developed. Chemotherapy was then carried out after the third procedure and the patient died 7 months later.

[Central neurocytoma: Study of 32 cases and review of the literature]. / Le neurocytome central : étude de 32 cas et revue de la littérature.

Central neurocytoma is a rare benign neoplasm of the central nervous system. The intraventricular location close to the Monro foramina and the attachment to the septum pellucidum are characteristic for the diagnosis. However, atypical appearances may be encountered and confused with other neoplasms. The authors report the radiological findings of 32 surgically treated and pathologically confirmed neurocytomas.

[Management of intramedullary spinal cord tumors: surgical considerations and results in 45 cases]. / Prise en charge neurochirurgicale des tumeurs intramédullaires : à propos de 45 cas.

BACKGROUND AND PURPOSE: Intramedullary spinal cord tumors (IMSCT) are relatively rare neoplasms, accounting for less than 5% of all central nervous system tumors. The optimum management of these tumors still remains controversial. Many decades ago, partial surgical resection followed by radiotherapy was the conventional management for IMSCT. Nowadays, maximal surgical resection of IMSCT without adjuvant therapy is the rule. We discuss the management of our cohort of 45 patients and review retrospectively the surgical outcome and survival. METHODS AND RESULTS: We reviewed the charts of 45 patients who underwent surgery for IMSCT in our institution since 1990. The study included 23 female and 22 male with a mean age of 28.7 years (range: 18 months-64 years). In 40 patients, the final diagnosis was based on the results of MR imaging. The cervical location of the tumor was the most common (20 cases). Surgical procedures included a gross-total resection in 31 cases, subtotal resection in six cases, partial resection in five cases and a biopsy in three cases. The large majority of patients had histologically-proven low-grade tumors composed essentially of astrocytomas (44,4%) and ependymomas (28,8%). There was no mortality related to surgery. Concerning the functional outcome at six months, we noted that 22.2% of our patients deteriorated, 47.3% stayed the same and 30.5% improved. We found that patients with mild or no preoperative deficits were exceptionally damaged by the surgical procedure. CONCLUSIONS: The gold-standard treatment of IMSCT remains maximal microsurgical resection without adjuvant therapy. For malignant or rapidly recurrent IMSCT, the optimum management is still controversial. Determinant predictors for a good outcome after surgery of IMSCT are histological type of lesion, total removal of the tumor and a satisfactory neurological status before surgery.

Potential energy scans and vibrational assignments of cyclopropanecarboxylic acid and cyclopropanecarboxamide.

The structural stability and internal rotations in cyclopropanecarboxylic acid and cyclopropanecarboxamide were investigated by the DFT-B3LYP and the ab initio MP2 calculations using 6-311G** and 6-311+G** basis sets. The computations were extended to the MP4//MP2/6-311G** and CCSD(T)//MP2/6-311G** single-point calculations. From the calculations the molecules were predicted to exist predominantly in the cis (C=O group eclipses the cyclopropane ring) with a cis-trans barrier of about 4-6kcal/mol. The OCOH torsional barrier in the acid was estimated to be about 12-13kcal/mol while the corresponding OCNH torsional barrier in the amide was calculated to be about 20kcal/mol. The equilibrium constant k for the cis<-->trans interconversion in cyclopropanecarboxylic acid was calculated to be 0.1729 at 298.15K that corresponds to an equilibrium mixture of about 85% cis and 15% trans. The vibrational frequencies were computed at the DFT-B3LYP level. Normal coordinate calculations were carried out and potential energy distributions were calculated for the low energy cis conformer of the molecules. Complete vibrational assignments were made on the basis of normal coordinate calculations and comparison with experimental data of the molecules.

[Hydrocephalus due to non tumoral stenosis of foramens of Monro: report of four cases]. / Hydrocéphalie par sténose non tumorale des trous de Monro: à propos de quatre cas.

Non tumoral stenosis of the foramen of Monro is rare; pathogenic mechanisms remain a subject of debate. The narrowing can be unilateral causing monoventicular hydrocephalus, and exceptionally bilateral causing biventricular hydrocephalus. We present two cases of monoventricular hydrocephalus and two other cases of biventricular hydrocephalus. Clinically, all patients had the same signs as in common hydrocephalus. The CT scan and mainly the MRI allowed us to confirm the diagnosis and to avoid tumor obstruction of the foramen of Monro. With neuroendoscopy we were able to describe the foramen of Monro and perform a fenestration of the septum pellucidum. The prognosis is usually good.

Hemangiopericytoma in the central nervous system. A study of eight cases.

Most hemangiopericytomas (HPC) are located in the musculoskeletal system and the skin, while the location in the central nervous system (CNS) is rare. The latter represents 2 to 4% in large series of meningeal tumors, thus accounting for less than 1% of all CNS tumors. In the central nervous system, tumors with a hemangiopericytomatous histolopathological pattern can be either hemangiopericytomas or solitary fibrous tumors. CNS-HPCs have a relentless tendency for local recurrence and metastases outside the CNS. Metastasis can also appear many years after adequate treatment of the primary tumor. We present a pathological study of eight patients with CNS-HPC and compare our results with corresponding published data. The CNS-HPC group consisted of three males and five females with a mean age of 36.75 years. The tumors were supratentorial in four cases, infratentorial in two cases, tentorial in one case and located in the spinal cord in the last one. Histologically, CNS-HPCs were similar to their soft tissue counterparts. One case demonstrated increased cellularity, marked nuclear hyperchromasia and marked cellular pleomorphism with infiltration of the cerebellum. All patients underwent surgery with gross-total resection in all cases. No patients received postoperative radiation therapy. Only four patients recurred locally after six, seven and eight months, and five years. Our study presents the pathological features of CNS-HPC as a distinct entity from both meningioma and solitary fibrous tumors. A comparative review of literature with our results is discussed.

Subependymomas: a clinicopathological study of 6 symptomatic cases.

BACKGROUND: Subependymomas are rare, slow-growing, ependymal neoplasms that commonly occur in the fourth or lateral ventricles. OBJECTIVE AND DESIGN: A retrospective study of 6 histologically proven subependymomas was undertaken to analyse their clinicopathological characteristics. RESULTS: There were five male and one female patients ranging in age from 11 to 50 years (mean 35.8 years). All patients were symptomatic at diagnosis. The most common clinical presentations included headache (n=6) and vomiting (n=3). Tumours were located in the lateral ventricle in five cases and in the fourth ventricle in one case. Magnetic resonance imaging detected obstructive hydrocephalus in all cases. Five patients underwent gross total resection and one patient had subtotal excision of the tumour. Histologically, all tumours were characterised by clustering of isomorphic cells arranged against a fibrillary background. Focal cystic degeneration was seen in 5 tumours. During the follow-up period, which ranged between 2 months and 10 years, all patients were symptom-free with no evidence of recurrence.

Osteite frontale post-sinusitique : etude retrospective a propos de 31 cas

Objectif : L'osteite frontale post-sinusitique est definie par l'extension de l'infection du sinus frontal aux structures osseuses adjacentes. Elle constitue une urgence diagnostique et therapeutique. Le but de ce travail est d'analyser les particularites epidemiologiques; cliniques et paracliniques; et de passer en revue les differentes attitudes therapeutiques devant cette pathologie. Materiel et methodes : Il s'agit d'une etude retrospective portant sur 31 patients diagnostiques et traites entre 1996 et 2010. Tous les patients ont beneficie d'un examen ORL et neurologique complet; d'un bilan biologique et d'une tomodensitometrie du massif facial et cerebrale. L'antibiotherapie a ete administree par voie intraveineuse. Le drainage chirurgical du sinus frontal se faisait soit par trepanation; soit par confection d'un volet frontal; soit par mise en place d'unclou de Lemoyne. Le drainage par voie endonasale comportait une meatotomie moyenne avec ethmoidectomie anterieure. La cranialisation du sinus frontal se faisait par voie coronale. L'evolution a ete evaluee sur des criteres cliniques; biologiques et radiologiques. Resultats : L'age moyen etait de 24;4 ans (8-62 ans) et le sex-ratio etait de 4;16. Les cephalees frontales (10 cas) et les signes d'hypertension intracranienne (8 cas) etaient les signes fonctionnels les plus frequents. Une tumefaction frontale etait notee chez 9 patients; associee dans 5 cas a une tumefaction orbitaire au niveau de l'angle interne de l'oeil. Les signes rhinologiques etaient domines par la rhinorrhee purulente (9 cas) et l'obstruction nasale (5 cas). L'endoscopie nasale trouvait du pus au niveau du meat moyen dans 12 cas. La TDM a revele un aspect typique d'osteite frontale sous forme d'un foyer d'osteolyse. Un abces sous-perioste etait associe chez 7 patients. Une extension intracranienne a ete notee dans 15 cas et orbitaire dans 7 cas. L'examen bacteriologique a mis en evidence un germe dans 8 cas. Les germes les plus frequents etaient le streptocoque et le staphylocoque aureus (3 cas pour chacun). Le traitement antibiotique a ete instaure d'emblee chez tous les patients. Pour le traitement chirurgical initial; 9 patients ont beneficie d'un drainage frontal et 2 autres d'un drainage orbitaire. Par ailleurs; 4 patients ont eu un drainage d'abces sous perioste seul. Celui-ci a ete associe a une cranialisation d'emblee dans un autre cas. Pour les patients ayant des complications endocraniennes; un drainage d'empyeme a ete realise dans 14 cas; associe chez 6 d'entre eux a une cranialisation d'emblee. Un drainage d'abces cerebral a ete pratique chez un autre patient. L'evolution clinique et radiologique a ete favorable chez 24 patients (77;4). Les sept autres patients ont necessite une reprise chirurgicale devant la persistance ou l'aggravation de la symptomatologie clinique. L'evolution ulterieure a ete favorable. Conclusion : L'osteite frontale post-sinusitique est une affection rare et grave. Son diagnostic; qui repose sur la clinique et l'imagerie; doit etre precoce. Un traitement adequat doit etre instaure afin de prevenir des complications qui peuvent mettre en jeu le pronostic vital

Primary central nervous system malignant melanoma: report of 5 cases.

Primary melanocytic neoplasms of the central nervous system consist of a spectrum of lesions ranging from well-differentiated melanocytoma to its overtly malignant counterpart, melanoma. Clinicopathologic features of 5 cases of primary central nervous system malignant melanoma were studied to define histologic appearances, diagnostic criteria, and the clinical behavior of lesions along this spectrum. There were three women and two men (mean age was 35 years) with symptoms of increased intracranial pressure. Radiological findings showed a solitary intra parenchymal lesion with variable enhancement after gadolinium administration. All patients underwent surgical treatment. Histologic examination revealed primary melanoma.

[Calcified cerebral hydatid cyst]. / Kyste hydatique cérébral calcifié A propos d'un cas exploré par IRM.

Hydatid cyst is rarely observed in the brain (0.5-4.5%). The frequency of calcified cyst is less than 1%. We present a case of a 15-year-old girl with a 5-year follow-up for grand mal seizures that became resistant to three-drug therapy. The CT scan revealed a calcified parieto-occipital lesion. MRI disclosed a suggestive detached membrane. At surgery, the cyst wall was calcified with typical hydatid sand contents. Since surgery, seizure control has been achieved with one drug. Calcification of a cerebral hydatid cyst is exceptional. MRI enabled the diagnosis in this patient.

Intracranial medulloepithelioma. A case report and review of the literature.

Medulloepithelioma is a rare primitive neuroectodermal tumour of the central nervous system usually developing in childhood, displaying highly malignant behaviour, with early progression or recurrence. The Authors report a new case of intracranial medulloepithelioma removed from the right cerebellar hemisphere of a 13-year-old boy who showed unspecific signs of intracranial hypertension. Based on a review of the thirty seven cases reported in the literature, they analyse the clinical, histological, immunohistochemical, ultrastructural and therapeutic features of this rare nervous system tumour.

[Hydatid cyst of the posterior fossa]. / Kyste hydatique de la fosse postérieure.

Hydatidosis is an endemic affection in Tunisia. Cerebral echinococcosis is a relatively rare entity accounting for only 1-2% of all hydatid cysts in humans. Extradural hydatid cyst of the posterior fossa is a very uncommon site for the disease. We report the case of a four-year-old child admitted for high intracranial pressure. Brain CT scan showed an extradural posterior fossa cyst without enhancement after contrast medium injection. Operative finding revealed a hydatid cyst. The histological examination of the tissue sample confirmed the diagnosis. The patient was given albendazole post operatively. She feels well six months later.

Rotational barriers in monomeric CH2=CX-COOH and CH2=CX-CONH2 (X is H or CH3) and vibrational analysis of methacrylic acid and methacrylamide.

The internal rotations in acrylic and methacrylic acids CH2=CX-COOH and their amides CH2=CX-CONH2 (X is H or CH3) were investigated by DFT-B3LYP calculations with 6-311+G** basis set. The potential energy curves were consistent with two minima that correspond to planar cis and trans conformation in the case of the acids (or cis and near-trans forms in the case of the amides). Acrylic acid and acrylamide were predicted to have the cis form as the low and predominant conformation of the molecules. In the case of the methacrylic acid and methacrylamide, the conformational relative stability was predicted to reverse as going from the acrylic to the metha compounds. The trans conformer in methacrylic acid or the near-trans in methacrylamide were predicted to be thermodynamically low energy structures of the molecules. The CCCO rotational barrier was calculated to vary from 4 to 6kcal/mol in the four molecules. The OCOH and OCNH torsional barriers were calculated to be about 13 and 22kcal/mol in the acids and the amides, respectively. The vibrational frequencies of methacrylic acid and methacrylamide were computed at the DFT-B3LYP/6-311+G** level and reliable vibrational assignments were made on the basis of normal coordinate analyses and comparison with experimental data of both molecules in their low energy conformations.

Atypical CT and MRI aspects of an epidermoid cyst.

We report a case of an unusual epidermoid cyst (EC) of the cerebellopontine angle that appeared hyperdense on computed tomography (CT) scanning, hyperintense on T1-weighted MR images and hypointense on T2-weighted magnetic resonance (MR) images. Diffusion-weighted imaging showed a hypointense lesion. We discuss imaging characteristics of ECs, explain the atypical findings in our case and confirm that the signal seen on diffusion-weighted images in the EC is related to a T2 effect.

Detection of cerebral aneurysms in nontraumatic subarachnoid haemorrhage: role of multislice CT angiography in 130 consecutive patients.

PURPOSE: The leading cause of a nontraumatic subarachnoid haemorrhage is rupture of an intracranial aneurysm. The aim of this study was to assess the usefulness of multislice computed tomography angiography (CTA) in identifying and evaluating cerebral aneurysms by comparing it with intra-arterial digital subtraction angiography (DSA) and intraoperative findings. MATERIALS AND METHODS: During a 20-month period (June 2004 and February 2006), 130 patients with a CT diagnosis of nontraumatic acute subarachnoid haemorrhage were prospectively recruited to this study and underwent 16-detector CTA and DSA (57 men, 73 women; mean age 59.5 years). Twenty-five patients who underwent DSA alone postclipping were excluded. CTA and DSA were evaluated by the performing radiologist to assess the presence of one or more aneurysms and their morphological characteristics. RESULTS: CTA detected 133 aneurysms, whereas DSA identified 134: the aneurysm missed by CTA was 2 mm in size. CONCLUSIONS: CTA is fast and relatively noninvasive, and its sensitivity appears similar to that of DSA in detecting and evaluating intracranial aneurysms, even those smaller than 3 mm. This study confirms the value of CTA as the primary imaging technique in subarachnoid haemorrhage, with DSA reserved for selected patients.

[Pituitary apoplexy. Report of 25 patients]. / Apoplexies pituitaires. A propos de 25 patients.

A series of 25 patients with a clinical diagnosis of pituitary apoplexy (PA) is reviewed. It included 14 men and 11 women aged between 20 to 79 years (mean age: 54 years). Twenty-two patients did not know that they had a pituitary tumor when the apoplexy occurred. A precipitating event was found in 3 cases. Symptoms and signs ranged from isolated ocular paresis to a deep coma. Seventeen patients experienced a decrease in their visual acuity. CTscan and MRI showed a pituitary adenoma in all cases, a hemorrhage was also present in 10 out of the 24 CTscans, and in all the 8 MRI performed. Twenty patients underwent surgery; 18 of them by a transsphenoidal approach. A complete recovery of visual acuity was observed in 75% of patients operated within the week following the onset of symptoms, and in 56% of patients operated later on. There was no case of complete visual recovery among the blind patients. Pituitary apoplexy is a clinical concept. It applies only to symptomatic cases. It is generally a complication of a pituitary adenoma which is in most cases unknown. There are different degrees of severity; PA can even be life-threatening. The principal aim of surgery in the acute phase is the improvement of visual prognosis. In our series, blind patients or those with a history of visual loss for more than a week or with a blindness had a poorer prognosis.

[Bone metastasis from a glioblastoma: An unusual course!]. / Métastase osseuse d'un glioblastome: évolution inhabituelle!

Extraneural diffusion of glioblastoma is very unusual. Extracranial metastases generally occur after craniotomy or a long survival time. Metastases usually involve the lungs, pleura, lymph nodes and occasionally the bone. We report herein a case of bone dissemination occurring 18 month after the initial diagnosis and treatment of supratentorial glioblastoma.