PubMed Health⌕ Search

Biomedical subjects

M Poza

Publications and source records attributed to M Poza.

At least 37 records · Page 2Linked to original sources
PubMed2001

[Training of neurosurgery residents].

It is not a trivial matter to think about the topic of training neurosurgeons in Spain. To raise the question, I review the requirements in several countries. I comment on the process of selection, the length of training, the control of quality in the training program and the opportunities for clinical research in hospitals and in basic neurosciences. I express my opinion against a compulsory final exam. I propose that residents should inform the local or regional Health and Education Authorities about the dedication of staff members to training of postgraduate doctors and that this report should be taken into account and compensated economically in a proportional way to their efforts.

Internship and Residency↗
PubMed2001

Analysis of canthaxanthin and related pigments from Gordonia jacobaea mutants.

A collection of 43 mutant strains of the bacterium Gordonia jacobaea was obtained by means of ethyl methanesulfonate treatment, and the strains were selected for their different pigmentation with respect to the wild-type strain. None of the mutants showed auxotrophy. They all showed good genetic stability and a growth rate similar to that of the parental strain. Canthaxanthin and other carotenoids from these mutants were extracted with acetone and ethanol and separated by high-performance liquid chromatography (HPLC). These HPLC analyses, together with spectrophotometric detection at 480 nm, revealed variations in the pigment contents of the different mutant strains.

Actinomycetales↗
PubMed2001

Characterization of a broad pH range protease of Candida caseinolytica.

AIMS: The study of a protease secreted by Candida caseinolytica for use in future industrial applications. METHODS AND RESULTS: Growth of Candida caseinolytica on a medium containing milk induced a rapid production of an extracellular enzyme able to hydrolyse casein. The crude extract was applied to both Sephacryl S-200 and DEAE-Biogel A columns, obtaining one peak of activity showing a molecular mass of approximately 30 kDa and three active peaks, respectively. These four peaks showed the same biochemical parameters. In all cases, an extremely broad pH range of action was determined. CONCLUSIONS: Candida caseinolytica secretes high levels of an extracellular protease when grown either in rotary shakers or in batch-fermenters. SIGNIFICANCE AND IMPACT OF THE STUDY: The biochemical properties of this enzyme suggest its possible industrial application in the brewing industry, in the formulation of certain type of detergents and in the fur and leather industries, among others.

Candida↗
PubMed2000

Ventriculopleural shunting with new technology valves.

Ventriculoperitoneal shunting constitutes the standard procedure for draining cerebrospinal fluid (CSF) in children with hydrocephalus. Ventriculoatrial and ventriculopleural shunting are alternative methods of CSF drainage, which have gained less acceptance. Ventriculopleural shunts are seldom used owing to justified fears of pneumothorax and symptomatic effusions of CSF. The addition of an antisiphon device to standard shunt systems seems to have prevented CSF pleural effusion. From 1988 to 1998, we treated each of six hydrocephalic children with a ventriculopleural shunt. In five cases we used new-technology valves designed to prevent the effects of siphoning with current differential pressure valves. Peritoneal adhesions, recent peritonitis, ascites, and obstruction of a previous ventriculoatrial shunt were the indications for pleural shunting. After a mean follow-up period of 2.5 years all shunts were functioning adequately. Only one patient showed transient symptoms of CSF overdrainage, which were corrected by up-grading the valve setting with the magnet. A late death was unrelated to the pleural shunting procedure. The use of valves of a new design designed to prevent overdrainage seems to account for the satisfactory outcomes observed in this series. We suggest that ventriculopleural shunting should be considered as the preferred alternative to peritoneal drainage in children with intra-abdominal adhesions or with a history of recent peritoneal infection.

Child↗
PubMed2000

Penetrating craniocerebral injury from an underwater fishing harpoon.

Weapon injuries other than gunshot wounds or low-velocity stab wounds to the head are extremely rare. We report the case of a 6-year-old girl who sustained a penetrating craniocerebral injury after being accidentally shot with an underwater fishing harpoon. This mechanism of injury seems to share characteristics of both high- and low-velocity projectiles. We discuss the management of this unusual injury in a child, remarking that foreign body removal in these cases must be carried out following the original direction of the projectile trajectory. We review the current literature on craniocerebral injuries caused by similar objects, especially those occurring in children.

Basal Ganglia↗
PubMed2000

Isolation and taxonomic study of a new canthaxanthin-containing bacterium, Gordonia jacobaea MV-1 sp. nov.

This article describes the isolation and taxonomic study of a coryneform isolate of a new Gordonia species (G. jacobaea), strain MV-1, which accumulates several carotenoids, including the ketocarotenoid trans-canthaxanthin. Identification of this new isolate by morphobiochemical methods did not allow unambiguous taxon assignment, but sequencing of the 16S rRNA gene clearly pointed to the genus Gordonia, Gordonia sputi being the closest fit. Differences in certain transversions/transitions in otherwise very well-conserved sequences of the described Gordonia species supported the proposal of this new taxon. The fact that both the best growth and best pigmentation were obtained with glucose, an inexpensive carbon source and at an industrially suitable temperature, suggests that this new bacterial strain may have good potential for the industrial production of canthaxanthin.

Actinomycetales↗
PubMed1999

Raised intracranial pressure in minimal forms of craniosynostosis.

Most cases of craniosynostosis are diagnosed during early infancy, but occasionally craniosynostosis evolves with minimal cranial involvement and goes unnoticed until late childhood. Seemingly these mild forms of craniosynostosis cause few, if any, symptoms of neurological involvement. We describe the cases of a 9-year-old girl and a 6-year-old boy who presented with evident signs of raised intracranial pressure (ICP), together with a negligible skull deformity. We have termed these cases as occult craniosynostosis. Differential diagnosis in our patients was established against known causes of benign intracranial hypertension. Bilateral expanding craniotomies afforded total relief from the symptoms and signs of raised ICP. Neurosurgeons treating children with symptoms and signs of benign intracranial hypertension should be aware of the possibility of minimal forms of craniosynostosis evolving with marked manifestations of raised ICP.

Child↗
PubMed1999

Development of a middle fossa arachnoid cyst. A theory on its pathogenesis.

The progression of congenital arachnoid cysts has seldom been documented. We report the case of a child who was diagnosed with arrested hydrocephalus at the age of 13 months. Neuroimaging studies performed when the girl was 22 months old showed the appearance of an arachnoid cyst in the right middle fossa, while the previously enlarged ventricles seemed to have decreased in size. To the best of our knowledge, the paradoxical expansion of an arachnoid pouch following a reduction in the size of the ventricular system has not previously been documented. We advance the hypothesis that the development of some cases of arachnoid cyst might be pathogenically related to impaired CSF dynamics associated with pre-existing hydrocephalus. We also briefly review the pertinent literature on the formation and evolution of congenital cerebral arachnoid cysts.

Arachnoid Cysts↗
PubMed1998

Avulsed lumbar vertebral rim plate in an adolescent: trauma or malformation?

Avulsion of lumbar vertebral rim plate is an uncommon lesion, seen specially in young adults. Its occurrence in pediatric age is very infrequent. As with intervertebral disc herniation in children, an accurate diagnosis may be often delayed due to concerns for neoplasm, infection, and spondylolisthesis. We report a 15-year-old boy with symptoms and myelographic details of disc protrusion. Plain radiographs, computerized tomography of the lumbar spine, and operative findings showed that the cause of root compression was a slipping of the entire disc together with the posterior rim plate at the L4-5 space. Pertinent literature on the subject is briefly reviewed. The proposed mechanism for apophyseal ring fracture is a combination of two factors: congenital insufficiency of the rim plate and injury to the lumbar spine.

Adolescent↗
PubMed1997

Atretic cephalocele in the adult.

Atretic cephaloceles are usually detected at birth. Recently we treated a 38-year-old man with one of these lesions, apparently the first report of this occurrence in an adult.

Adult↗
PubMed1997

Disc protrusion in the child. Particular features and comparison with neoplasms.

Lumbar intervertebral disc herniation, although common in adults, is infrequent in the young, and especially in patients under 17 years old. In this work we review clinical data pertaining to two pediatric groups of patients whose main complaint was low back pain and/or sciatica, trying to identify factors that might contribute to their earlier referral and to the differential diagnosis of protruded disc and spinal neoplasm in this population. Group A comprises 17 youngsters diagnosed as having lumbar herniated nucleus pulposus and group B, 16 children with neoplasms of the lower thoracic and lumbosacral regions. Both groups were similar in sex distribution and symptoms of pain and numbness. However, there was a striking difference in age at presentation. No patient in group A was younger than 11 years, while most of those in group B were in their first decade of life (P = 0.018). The classic clinical onset in the children with herniated discs started with low back pain and sciatica, as in the children with neoplasms, although in subgroup B leg pain tended to be bilateral. The usual examination findings in both groups were spinal rigidity and sensory loss, but motor weakness and impaired reflexes were found to be more frequent in the group with spinal growths (P = 0.02). Children with lumbosacral neoplasms also tended to present with atypical symptoms (acute onset, intracranial hypertension, subarachnoid hemorrhage and abdominal pain), while this was the exception in the group with herniated discs. Plain radiographs of the pediatric spine showed that X-ray examination is still a good tool for diagnosing spinal growths compared with their scant utility in disc herniations (P = 0.001). During the survey we were impressed by the children's apparent good tolerance to pain, which is probably due to the lack of the emotional component of pain in adults and explains their delayed referral for neurosurgical consultation. However, all modalities of treatment seemed to be effective in children, chemonucleolysis and surgery being extraordinarily effective in this age group. Accordingly, we see no reason for long-term conservative therapy in children with lumbar and sciatic pain; on the contrary, we believe these patients should be offered earlier neurosurgical treatment.

Adolescent↗
PubMed1997

Posttraumatic intradiploic arachnoid cyst of the posterior fossa.

We report the case of a 5-year-old girl with an enlarging suboccipital mass, a posttraumatic intraosseous arachnoid cyst. Diagnostic work-up revealed that the lesion consisted of an intradiploic arachnoid cyst and an extra-axial occipital pouch that communicated by way of an osseous and dural defect. Surgical repair was undertaken with good results. A search of the current literature has shown only seven previous reports of leptomeningeal cysts situated at the occipital bones, most of them the result of an antecedent skull fracture. A pathogenetic hypothesis is presented comparing the growth of arachnoid intraosseous cysts and the development of meningocencephaloceles.

Arachnoid Cysts↗
PubMed1997

Primary malignant rhabdoid tumor of the cerebellum.

Malignant rhabdoid tumor (MRT) is a recently described variety of childhood renal neoplasm. MRT arising primarily in the central nervous system (CNS) is still a rather unfamiliar pathological entity and is frequently misdiagnosed as medulloblastoma or primitive neuroectodermal tumor (PNET). We describe a 7-month-old boy who harbored a CNS-MRT that originated within the IV ventricle and invaded the brain stem and the cerebellar hemispheres. After an initial documented good response to chemotherapy the tumor recurred locally 9 months after operation. We discuss clinical and histopathological features distinguishing between PNET/medulloblastoma and MRTs. Current literature on MRT of the CNS is briefly reviewed.

Cerebellar Neoplasms↗
PubMed1997

Extradural dermoid tumours of the posterior fossa.

Dermoid tumours in children usually occur in two locations: at the anterior fontanelle and on the occipital squama. An exceptional site of origin for a posterior fossa dermoid cyst is the extradural space. There are only six previous cases of this situation reported in the literature. A series of 103 subscalp and calvarial masses in children were reviewed and three children are reported with extradural dermoids of the posterior fossa, which communicated with the skin through midline occipital dermal sinuses. All three children were seen after the rapid growth or the formation of an abscess in a previously noted occipital subcutaneous mass present since birth. Although computed tomography or magnetic resonance imaging showed the dermal sinus and the intracranial tumour, these studies were unable to ascertain the intradural or extradural nature of the tumours, their exact origin only being established at operation. Histopathological study showed preclinical signs of infection in the two patients that had not yet formed an abscess. It is suggested that early neurosurgical treatment of these neoplasms should be done to prevent the development of severe intracranial infection. The previously reported simplicity of surgical removal of occipital extradural dermoids was not confirmed in this series.

Brain Abscess↗
PubMed1997

Iatrogenic intradiploic meningoencephalocele. Case report.

The authors present the case of a 6-year-old girl who developed a right frontal intradiploic meningoencephalocele following an accidental dural tear produced during surgery for craniosynostosis. Although rare, growing skull fractures have been described in at least eight cases following the accidental laceration of the dura mater in the course of craniosynostosis repair. These cases closely resemble those produced by accidental trauma to the growing skull. However, the intradiploic location of a meningoencephalocele following surgery for craniosynostosis has not been documented previously. This patient presented with headache and a frontal tumor of bonelike consistency. Radiographs and computerized tomography scans of the skull revealed an intraosseous cyst, whereas magnetic resonance imaging demonstrated cerebral tissue herniation within the intradiploic tumor. Surgical treatment consisted of duraplasty and cranioplasty, which achieved good functional and cosmetic results. The pathogenesis of this unusual lesion is discussed and compared with the hypotheses advanced for explaining posttraumatic intradiploic cysts.

Child↗
PubMed1996

The child with a cephalocele: etiology, neuroimaging, and outcome.

We report a series of 46 children who were treated for one of the diverse forms of cranium bifidum during a period of 22 years. The purpose of the survey was to investigate pathogenetic factors involved in the development of cranial dysraphism and to analyze clinical and pathological factors that influence the patients' outcome. We also investigated the existence of associated intracranial anomalies, in a systematic way, using modern methods of neuroimaging, and related the findings to the patients' final results. The lesions were classified as encephalocele (n = 15), cranial meningocele (n = 3), atretic cephalocele (n = 26), cranium bifidum occultum (n = 1), and exencephaly (n = 1). There was an excess of the atretic form of cephaloceles in our series, a fact that probably reflects geographical variations described for cephaloceles in general. The location of the lesions was occipital in 29 children, parietal in 16, and temporal and frontobasal in one case each. In seven cases there was parental consanguinity. A familial history of malformations of the central nervous system was encountered in eight instances. Associated systemic abnormalities were present in 23 patients, while central nervous system anomalies were found in 36 children. Cephalocele repair was undertaken on 35 occasions. There were no surgical fatalities in the series. The mean follow-up time was of 7 years. Overall mortality for the whole group was of 17/46 or 36%. Twenty of the 29 survivors had no neurological sequelae, but only 18 children exhibited a competitive intelligence level. A good outcome was found to correlate well with: an average head size at birth, a normal initial neurological condition, operability of the lesions, and an absence of disorders of the neuronal migration. Neurological outcome depended also on the occurrence or not of hydrocephalus, while the intelligence level was mainly related to the absence of cerebral tissue within the sac of the malformation.

Abnormalities, Multiple↗
PubMed1996

Unusual osteolytic midline lesion of the skull: benign osteoblastoma of the parietal bone.

The authors report the case of a 5-year-old girl who presented with a parietal midline sub-scalp lesion. Skull radiographs demonstrated a lytic lesion surrounded by a sclerotic rim that resembled a dermoid cyst of the cranium. Histopathological analysis proved that the lesion was a benign osteoblastoma. As in other calvarial masses of uncertain nature, after diagnostic workup, we recommend surgical excision both for diagnosis and for treatment.

Child, Preschool↗