The nigrostriatal system in the presymptomatic and symptomatic stages in the MPTP monkey model: a PET, histological and biochemical study

Parkinson's disease (PD) is diagnosed when striatal dopamine (DA) loss exceeds a certain threshold and the cardinal motor features become apparent. The presymptomatic compensatory mechanisms underlying the lack of motor manifestations despite progressive striatal depletion are not well understood. Most animal models of PD involve the induction of a severe dopaminergic deficit in an acute manner, which departs from the typical, chronic evolution of PD in humans. We have used 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) administered to monkeys via a slow intoxication protocol to produce a more gradual development of nigral lesion. Twelve control and 38 MPTP-intoxicated monkeys were divided into four groups. The latter included monkeys who were always asymptomatic, monkeys who recovered after showing mild parkinsonian signs, and monkeys with stable, moderate and severe parkinsonism. We found a close correlation between cell loss in the substantia nigra pars compacta (SNc) and striatal dopaminergic depletion and the four motor states. There was an overall negative correlation between the degree of parkinsonism (Kurlan scale) and in vivo PET ((18)F-DOPA K(i) and (11)C-DTBZ binding potential), as well as with TH-immunoreactive cell counts in SNc, striatal dopaminergic markers (TH, DAT and VMAT2) and striatal DA concentration. This intoxication protocol permits to establish a critical threshold of SNc cell loss and dopaminergic innervation distinguishing between the asymptomatic and symptomatic parkinsonian stages. Compensatory changes in nigrostriatal dopaminergic activity occurred in the recovered and parkinsonian monkeys when DA depletion was at least 88% of control, and accordingly may be considered too late to explain compensatory mechanisms in the early asymptomatic period. Our findings suggest the need for further exploration of the role of non-striatal mechanisms in PD prior to the development of motor features.

[Bladder malformations in a model of myelomeningocele. Preliminary report]

PURPOSE

To describe the presence of bladder malformations in a surgically induced model of myelomeningocele (MMC).

METHODS

A MMC like defect was created in the mid gestation using the previously described model in sheep. Bladders were examined macroscopically and histopathological changes were assessed using H-E.

RESULTS

Non prenatally corrected animals presented dilated bladders and separation between muscle bundles. Those malformations were not found in corrected animals or controls.

CONCLUSIONS

Some bladder changes can be described in a surgically-induced model of MMC. These changes could be prevented using open fetal surgery.

[Prenatal techniques to prevent central nervous system malformations in the surgically induced model of myelomeningocele]

AIM

To describe central nervous system malformations in the surgically induced model of Myelomeningocele (MMC) and their prevention using different prenatal treatments.

METHODS

MMC was surgically created in 33 fetal lambs. Fifteen did not undergo fetal repair (group A). Of the lambs that did undergo repair, 10 were repaired with open two layer surgical closure (group B), 5 with fetoscopic coverage using bioglue (group C) and 3 fetoscopically using a patch (group D). All procedures were recorded and lamb brains and spinal cords were examined grossly and microscopically in coronal sections for structural organization anomalies. Histopathological changes were assessed using HE and S-100 neural marker.

RESULTS

Hydrocephalus, Arnold-Chiari type II (AC-II) malformation and some neuronal migration disorders were observed in group A. Brains from group B and D were not hydrocephalic and had neither cell migration disorders nor hindbrain herniation. Group C presents mild degrees of hydrocephalus and AC-II. In group C lumbar lesion was covered by fibrous tissue.

CONCLUSIONS

Some of the central nervous system abnormalities observed in human disease are present in the surgically induced model of MMC. In this model avoidance of fluid drainage using open fetal surgery limits malformation severity.

Brain malformations in the sheep model of myelomeningocele are similar to those found in human disease: preliminary report

PURPOSE

To examine if brain malformations, similar to those which account for cognitive disorders seen in human disease, are present in an ovine model of myelomeningocele (MMC).

METHODS

An MMC-like lesion was surgically created in 16 fetal lambs between 60 and 80 days of gestation. Ten did not undergo fetal repair (group A), 2 were repaired with an open two-layer closure (group B), 2 with open bioglue coverage (group C) and 2 with fetoscopic coverage (group D). Lambs were killed and their brains were examined. Two brains from normal unoperated lambs served as controls.

RESULTS

Thirteen lambs died in utero (81%). Two lambs in group A and 1 in group B were delivered at term. Group A brains showed hydrocephalus and extensive areas of polymicrogyria. There was also an extensive denudation of the ependymal lining under the polymicrogyric areas and the corpus callosum was thinner than normal. No hindbrain herniation was observed. Brains from group B and the control did not show any of these abnormalities.

CONCLUSIONS

Some of the central nervous system abnormalities associated to MMC in human patients are also found in the uncorrected fetal lamb model of MMC but not in the only survivor to intrauterine coverage. Further studies are necessary to ascertain if these abnormalities can be prevented by coverage of the defect.

Phospholipid hydroperoxide glutathione peroxidase (PHGPx) expression is downregulated in poorly differentiated breast invasive ductal carcinoma

Phospholipid Hydroperoxide Glutathione Peroxidase (PHGPx) is the only known enzyme able to reduce lipid peroxides bound to cell membranes. Moreover it has been involved in apoptosis and can influence intracellular signaling. To investigate the possible relationship between PHGPx and human cancer we have quantified PHGPx expression levels by real-time quantitative PCR and immunohistochemistry in tissue samples of human breast invasive ductal carcinoma from 34 patients compared with their own controls of benign breast tissue. PHGPx expression levels were compared with the clinical and pathological data of these patients. The results showed that PHGPx expression levels are downregulated in poorly differentiated (grade 3) breast invasive ductal carcinoma (P = 0.0043). PHGPx expression levels decreased gradually with tumor grade from grade 1 to grade 3. We also found a downregulation of PHGPx in cases that showed p53 accumulation compared with cases without p53 immunostaining (P = 0.0011). PHGPx was also downregulated in cases without progesterone receptors (PR) immunostaining compared with cases with PR immunostaining (P = 0.0165). Grade 3, p53 immunostaining and absence of PR immunostaining are poor prognostic factors. These results suggest that PHGPx downregulation could be related with a poorer prognosis in breast invasive ductal carcinoma.

Immunohistochemical expression of p53, Bcl-2, COX-2, C-erb-B2, EPO-R, beta-catenin, and E-cadherin in non tumoral gastric mucous membrane

Different authors have investigated the immunohistochemical expression of some proteins in the adenocarcinoma of the stomach, including cell cycle regulators proteins like p53 and Bcl-2; growth factors (c-erb-B2 and EPO-R); angiogenesis-related markers such as COX-2 and cellular adhesion molecules (beta-catenin and E-cadherin). While these proteins have been studied in gastric adenocarcinoma, their immunophenotyping in non tumoral gastric mucous membrane remains unexplored. In the present study, we investigated the expression, function and behavior of these proteins in normal gastric mucous membrane to contribute to gain further knowledge on the significance of their loss or overexpression in malignant gastric tumors.

The oncogene BRAF V600E is associated with a high risk of recurrence and less differentiated papillary thyroid carcinoma due to the impairment of Na+/I- targeting to the membrane

The oncogene BRAF(V600E) is the most frequent genetic event in papillary thyroid carcinoma (PTC) but its prognostic impact still remains to be elucidated. We evaluated a representative series of 67 individuals with PTC who underwent total thyroidectomy. BRAF-positive tumours correlated with early recurrences (32% vs 7.6%; P=0.02) during a median postoperative follow-up period of 3 years. Interestingly, within the recurrences, a significant majority had negative radioiodine ((131)I) total body scans, predicting a poorer outcome as treatment with (131)I is not effective. This last observation led us to investigate the role of BRAF(V600E) and the MEK-ERK pathway in thyroid dedifferentiation, particularly in Na(+)/I(-) symporter (NIS) impairment, as this thyroid-specific plasma membrane glycoprotein mediates active transport of I(-) into the thyroid follicular cells. A subset of 60 PTC samples was evaluated for NIS immunoreactivity and, accordingly, we confirmed a significant low NIS expression and impaired targeting to membranes in BRAF-positive samples (3.5% vs 30%; P=0.005). Furthermore, experiments with differentiated PCCl3 thyroid cells demonstrated that transient expression of BRAF(V600E) sharply impaired both NIS expression and targeting to membrane and, surprisingly, this impairment was not totally dependent on the MEK-ERK pathway. We have concluded that BRAF(V600E) is a new prognostic factor in PTC that correlates with a high risk of recurrences and less differentiated tumours due to the loss of NIS-mediated (131)I uptake.

Localisation of COX-2 protein is different in breast ductal carcinoma and adjacent non-tumour ductal epithelium

INTRODUCTION

A number of findings suggest that cyclooxygenase-2 (COX-2) is overexpressed in breast tumours. However, there is a lack of consensus in the literature regarding the pattern of expression of this protein in invasive breast ductal carcinoma and in the adjacent non-tumour ductal epithelium. This study compares the expression of COX-2 mRNA and protein in breast ductal carcinoma relative to non-tumour breast tissue.

MATERIAL AND METHODS

We analysed the expression of COX-2 mRNA by quantitative PCR, and COX-2 protein by immunohistochemistry in invasive ductal carcinoma as well as in non-tumour adjacent ductal epithelium from 34 breast biopsies diagnosed as being invasive ductal carcinoma. As control, we analysed expression of COX-2 protein by immunohistochemistry in surgically-resected benign breast lesions.

RESULTS

Our results show that COX-2 mRNA and protein are overexpressed in non-tumour ductal epithelium compared with invasive ductal carcinoma. However, the pattern of the protein expression is different in tumour and non-tumour tissue: COX-2 protein is expressed predominantly in the membrane of the non-tumour ductal epithelium (including in benign breast lesions) while, in invasive ductal carcinoma cells, it is localised in the cytoplasm.

CONCLUSIONS

The non-tumour ductal epithelium adjacent to invasive ductal carcinoma shows a higher COX-2 expression than does the invasive ductal carcinoma. However, the different localisation of the immunohistochemically-detected protein suggests a possible post-translational regulation of the protein.

Neonatal spinal muscular atrophy with multiple contractures, bone fractures, respiratory insufficiency and 5q13 deletion

We present the case of a floppy neonate with marked and generalized weakness, respiratory insufficiency and fetal akinesia deformation sequence. The infant showed multiple joint contractures, two bone fractures and needed mechanical ventilation from birth to death at 16 days of age. Electrophysiological assessment showed electrically unexcitable motor and sensory nerves. Muscle biopsy showed diffuse atrophy of type I and type II fibers. Necropsy confirmed the diagnosis of infantile spinal muscular atrophy (SMA) with severe loss of motor neurons in anterior horns and motor nuclei of brainstem. There were also neuronal loss, gliosis, chromatolysis, ballooned cells, empty cell beds and neuronophagia figures in other brainstem and brain nuclei. Genetic analysis of the patient revealed homozygous deletions of survival motor neuron gene 1 (SMN1) and a single copy of SMN2 in region 5q13. This case confirms that the loss of spinal motor neurons underlies the muscular atrophy in severe cases of 5q SMA. This case also shows that the presence of multiple joint contractures, bone fractures and respiratory insufficiency in SMA in the neonatal period does not necessarily exclude the occurrence of classical deletions in the SMA 5q13 region. Rather, these atypical clinical findings show the extreme severity and prenatal onset of the disease in these SMA cases, which may be related with the occurrence of a single copy of SMN2 gene. More reports of clinically, pathologically and genetically well-documented cases are essential to define the different types of this disease.

Adenomatous hyperplasia of the rete testis. A review and report of new cases

Adenomatous hyperplasia of the rete testis (AHRT) is an uncommon benign lesion that preferentially involves the septal rete testis and mediastinal rete testis. It is usually an incidental finding in surgical specimens from cryptorchidism and testicular tumour. It can be found in autopsy specimens from patients dying with different chronic diseases and newborns with kidney diseases. Since its first description many articles have been published communicating new cases and putting forward some hypotheses on its aetiology and pathogenic mechanisms. Some authors suggest a role for hormonal changes, tumour invasion and action of chemical agents. We think that AHRT should be categorised into two main aetiological categories: congenital and acquired. The cases associated with different kidney and spermatic duct diseases, most cases associated with cryptorchidic testis and some cases associated with testicular germ cell tumour should be included in the congenital group. The remaining cases associated with chemical agents, some hormonal changes (i.e. androgen blockade) and most of the germ cell tumour cases can be considered as acquired AHRT. Differential diagnosis must be established mainly with metastatic adenocarcinoma of prostate to testis and primary adenocarcinoma of the rete testis. Pseudohyperplasia of the rete testis must also be considered in atrophic testes. Here we review the papers published on this subject and report our recent cases.