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 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.

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.

[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.

[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.

Intrasphenoidal rathke cleft cyst.

Symptomatic Rathke cleft cysts (RCC) are reported in the sellar and suprasellar regions, but no case of sphenoidal RCC has been reported. We report a case of sphenoidal RCC in a 41-year-old man. The lesion was revealed by headaches and diplopia. Symptoms disappeared transiently after a spontaneous rhinorrhea but relapsed 4 months later. MR imaging showed a cystic sphenoidal lesion, isointense on T1-weighted images (WI) with peripheral gadolinium enhancement and hyperintense on T2 WI. The patient underwent surgery through a transrhinoseptal approach. The wall of the sphenoid sinus was paper-thin. The cyst contained a motor-oil-like fluid and communicated widely with the nasal fossa. Its wall was partially extracted. Symptoms and signs ceased after surgery. MR imaging performed 1 year later showed the disappearance of the sphenoidal cyst. Embryological origin of RCCs is discussed. The hypothesis of a continuum between the different epithelial cystic lesions of the sellar and parasellar region is discussed. Imaging has an important impact on the diagnosis; nevertheless, the specific characterization remains difficult.

[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.

[Sellar hemangiopericytoma. A case report]. / Hémangiopéricytome sellaire. A propos d'un cas.

Primary central nervous system hemangiopericytoma is rare, accounting for less than 1% of primary central nervous system tumors. Diagnosis is histological. Treatment is surgical excision, followed by radiotherapy. Long-term follow-up is mandatory for these tumors with a high potential for recurrence and metastasis. The sellar location is very rare, and can be confused with pituitary adenoma. We report the case of a patient presenting a sellar hemangiopericytoma, who underwent surgery via a transsphenoidal approach, then right frontal craniotomy followed by radiotherapy. There was no recurrence at one year follow-up.

[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.

[Aneurysmal bone cyst of the cranial base treated by partial resection and calcitonin injection. A case report]. / Kyste anevrysmal de la base du crane. à propos d'un cas traité par exérèse partielle et injection de calcitonine.

STUDY DESIGN: First published report of a cranial aneurysmal bone cyst (ABC) treated successfully with intralesional injection of calcitonin. OBJECTIVES: To describe a safe and effective treatment method for ABCs of the cranial base. SUMMARY OF BACKGROUND DATA: ABC is a rare form of dystrophic pseudotumor. Less than 100 cases involving the skull have been reported in the literature, most of them localised in the cranial vault. Cranial base locations are rare and difficult to treat. We selected this treatment after a very rapid recurrence of the lesion following a partial resection. Method. - After a partial resection of a 10 cm petro-occipital ABC that encased the vertebral artery and the lower cranial nerves, an Ommaya reservoir was implanted with a catheter tip inside the ABC. Repeated intralesional injections of calcitonin were performed through the reservoir. RESULTS: Shrinkage of the cyst occurred with disappearance of its heterogeneous cystic content and ossification of its walls. There was no complication and the lesion remains quiescent at a 3 year follow-up. CONCLUSION: We reviewed the pertinent literature concerning percutaneous treatment of ABC. The percutaneous intralesionnal injection of calcitonin was reported in the literature only in 3 publications reporting 9 cases that did not involve the skull. This treatment seems safe and effective, worthy in cranial base ABCs that are difficult to resect completely.

Mesenchymal extraskeletal chondrosarcoma of the orbit. Report of a case and review of the literature.

BACKGROUND: Extraskeletal mesenchymal chondrosarcoma (MCS) is relatively uncommon. Orbital location is extremely rare: only 16 cases have been reported until now. We report a case of extraskeletal mesenchymal chondrosarcoma in a 27-year-old man and review the literature on its manifestations and management. CASE REPORT: This patient had a 2-year history of progressive proptosis of the right eye. Skull X-ray and CT scan showed intraorbital calcification and a large lesion in the upper right orbit. He was operated three times because of recurrence of the tumor. The last recurrence was observed to have extension to the intracranial region, detected on MRI and CT scan. This secondary extension of the tumor to the intracranial region has not been previously reported. Immunohistochemical analysis for S-100 protein showed focal positivity. CONCLUSION: Mesenchymal chondrosarcoma of the orbit is rare, and secondary extension to the intracranial region has not previously been reported.

[Chemodectoma of the orbit. Apropos of a case and review of the literature]. / Chémodectome de l'orbite. A propos d'un cas et revue de la littérature.

The clinical, follow up and diagnostic features of a case of chemodectoma (paraganglioma) of the orbit are reviewed. 30 cases are reported in the literature. Chemodectoma may arise in any area of the body where non chromaffin paraganglion structures are situated. These are localized in the orbit of the chimpanzee but not in the orbit of man. Malignant behavior of chemodectoma has been a controversial subject, with most authors considering them to be benign tumors. Some authors have diagnosed locally recurrent and infiltrative tumors as malignant. The authors report one case of chemodectoma of the orbit. A 5 year old child has had right exophthalmos. She was treated by tumorectomy. The follow-up is marked by recurrence of the tumor and infiltration of the right hemi-face.

[Solitary plasmacytoma of the cranial vault. Case report and review of the literature]. / Plasmocytome solitaire de la voûte crânienne. A propos d'un cas et revue de la littérature.

We report a case of solitary plasmacytoma of the cranial vault. A 58-year-old man presented with a frontal soft tissue mass. X-Ray of the skull showed a lytic lesion of the frontal bone. CT scan showed the lesion extending intra and extracranially and cerebral angiography allowed embolization of afferent arteries. Complete removal of the lesion was performed without additional radiotherapy. Two years after surgery the patient is alive, and asymptomatic. Until 1997, 35 cases of solitary plasmacytoma of the cranial vault are reported, of which only five had frontal localisation. Solitary plasmacytoma of the cranial vault has a good outcome but progression towards a multiple myeloma is possible and deserves clinical and biological follow-up.

[A symptomatic choroid plexus cyst in the lateral ventricle]. / Kyste symptomatique du plexus choroïde du ventricule latéral.

Choroid plexus cyst is generally small and a relatively common finding at autopsy. Huge and symptomatic cysts are rare. Few cases are reported in the literature. We report one case of symptomatic choroid plexus cyst of the right lateral ventricle in a six month baby who presented with epilepsy. Cerebral CT scan and MRI showed a large cyst in the right lateral ventricle compressing the adjacent structures. Total removal of the cyst has been performed by a parieto-temporal approach. The course was uneventful.

[Cerebral aspergillotic granuloma. Apropos of a case and a review of the literature]. / Granulome aspergillaire cérébral. A propos d'un cas et revue de la littérature.

The authors report a case of aspergillus granuloma of the brain, in a 28 year old woman, simulating a meningioma. Preoperative diagnosis of aspergilloma is difficult. However, it may be suspected in a patient who has associated pulmonary and paranasal sinus fungal infection. Peroperatively it may be confused with a brain tumour. The lesions usually are in the frontal lobes. Diagnosis can be made only by surgical biopsy with identification of fungal elements. Granuloma induce a good host response, and a high capacity to elaborate antibodies.

[Cerebral stereotactic biopsy and surgery: Report of 100 cases]. / La biopsie et la chirurgie cérébrales en conditions stéréotaxiques: a propos de 100 observations.

OBJECTIVE: To report the results of the use of the stereotactic techniques in the management of intra cranial lesions. MATERIALS AND METHODS: Between july 1994 and march 1998, we carried out 117 stereotactic procedures of whom only 100 cases were analyzed. All the procedures were achieved after a CT scan. Patients were separated in two groups: (A) stereotactic biopsy (91 patients), (B) surgery with laser guidance (9 patients). The mean age in group A was 38 years (2-75 years) versus 27 years (11-66 years) in group B. The sex-ratio was 1.3. RESULTS: In the group A, the correct pathological diagnosis was obtained in 91.2% of cases. Glial tumors was the frequent histopathological variety of tumor (67.47%). Only one patient was operated after biopsy for a bilateral meningioma of the anterior 1/3 of the falx. There was only one death (1.09%) and 3.29% of transitory complications. In the group B, all patients were operated with laser guidance. Thirty seven per cent of patients underwent radiotherapy after the stereotactic biopsy or surgery. CONCLUSION: Stereotactic biopsy is a reliable method for the histopathological diagnosis of deep-seated brain lesions. Surgery with laser guidance is a useful alternative for the management of small deep-seated lesions or lesions located in functional areas.