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A Poranen

Publications and source records attributed to A Poranen.

15 recordsLinked to original sources
PubMed2001

Gain of chromosome 3 and loss of 13q are frequent alterations in pituitary adenomas.

Genetic changes underlying the tumorigenesis of pituitary adenomas (PA) are poorly characterized. To search for characteristic genomic imbalances involved in PA, we examined 38 cases: 12 hormone-secreting (HS) and 26 non-functioning (NF) PA, by comparative genomic hybridization. The most frequent DNA copy number change in both kinds of tumors was loss of 13q. Gains of chromosomes 3, 7 and 14, 6p, and 20q were more frequent in HSPA than in NFPA. These data indicate that the 13q region may harbor tumor suppressor genes determining the tumorigenesis of PA and gain in chromosome 3 may be related to hormone secretion. These findings provide a basis to search for candidate diagnostic markers of HSPA.

Adenoma↗
PubMed1999

Ovarian hyperstimulation caused by gonadotroph adenoma secreting follicle-stimulating hormone in 28-year-old woman.

Ovarian hyperstimulation caused by a gonadotroph adenoma in premenopausal women has been described only twice before this report. A 28-yr-old woman presented with menstrual disturbances and pelvic pains that began after stopping the use of contraceptive pills. Transvaginal ultrasound revealed enlarged ovaries with multiple cysts. The patient had elevated serum estradiol (up to 2900 pmol/L; normal, 80-300 pmol/L in the follicular phase) and inhibin (6.4 kU/L; normal, 0.5-2.5 kU/L) levels. Serum LH was appropriately suppressed (0.6 IU/L), but serum FSH varied from 4.9-8.1 IU/L. Both gonadotropins as well as the free alpha-subunit showed a paradoxical response to the stimulus by TRH. A nuclear magnetic resonance study unraveled a pituitary tumor, 12-14 mm in diameter, extending up to the suprasellar cistern. After pituitary surgery, all hormone values normalized, and the patient resumed regular ovulatory cycles. In immunostaining, 20-30% of the cells of the tumor stained positively for FSHbeta. We conclude that a gonadotropin-producing adenoma must be considered in the differential diagnosis of a patient presenting with large multicystic ovaries and high estradiol levels in the absence of exogenous gonadotropins.

Adenoma↗
PubMed1994

Hyponatremia after transsphenoidal surgery for pituitary tumors.

We studied the incidence of postoperative hyponatremia in 91 consecutive patients (44 males and 47 females; age, 45 yr; range, 12-76) operated on transsphenoidally for pituitary tumors. A postoperative serum sodium concentration less than 135 mmol/L (the lowest, 109 mmol/L) was observed in 32 (35%) patients. Hyponatremia occurred most commonly in patients operated on for Cushing's disease (11 of 18 patients; 61%). Hyponatremia was symptomatic in 18 (56%) of the patients. Neither the size nor the operability of the tumor or transient postoperative polyuria predicted the development of hyponatremia. Hyponatremia was first observed on the sixth or seventh postoperative day. The patients were treated with water restriction and by increasing the hydrocortisone replacement dose in the case of ACTH deficiency, and recovery took place, on the average, within 5 days. High urinary osmolality and plasma arginine vasopressin concentration during hyponatremia in a subgroup of study patients with these measurements indicated that inappropriate vasopressin secretion was involved in the pathogenesis of hyponatremia. In conclusion, postoperative hyponatremia after transsphenoidal surgery is common and may put the patients at increased risk of severe hyponatremic symptoms. Therefore, all patients should be screened for serum electrolytes for 1 week after transsphenoidal surgery.

Adenoma↗
PubMed1989

The treatment of spontaneous intracerebral hemorrhage. A prospective randomized trial of surgical and conservative treatment.

In a prospective study, 52 patients with a spontaneous supratentorial intracerebral hematoma (ICH) were randomly assigned to receive emergency surgery or conservative treatment within 48 hours after the bleed. Patients with a decreased level of consciousness and/or a severe neurological deficit were admitted to the study. The overall mortality rate at 6 months was 42%: 10 (38%) of the 26 patients in the conservative group and 12 (46%) of the 26 in the surgical group. Six (20%) of the 30 survivors at 6 months were able to conduct their activities of daily living independently: five (31%) of the 16 patients in the conservative group and one (7%) of the 14 in the operative group. These differences are not statistically significant. The mortality rate of semicomatose or stuporous patients (Glasgow Coma Scale score 7 to 10) was statistically significantly lower in the surgical group (none of the four patients) than in the conservative group (four of five patients) (p less than 0.05); however, all surviving patients in this subgroup were severely disabled. The study suggests that surgical treatment of this category of patients with ICH does not offer any definite advantage over conservative treatment. In semicomatose or stuporous patients, surgery may improve the length of survival, but the quality of life remains poor.

Adolescent↗
PubMed1988

Acute surgery for intracerebral haematomas caused by rupture of an intracranial arterial aneurysm. A prospective randomized study.

In a randomized prospective study, 15 patients with an intracerebral haematoma caused by an intracranial aneurysm were treated concervatively and 15 operated on as an emergency. Mortality was 12/15 (80%) in the conservative group and 4/15 (27%) in the surgical group. The difference is statistically significant. The deaths in the conservative group were caused by both the primary haematoma and rebleeding. The results suggest that intracerebral haematomas caused by rupture of an intracranial aneurysm should be evacuated immediately, and that the aneurysm should be clipped at the same operation.

Adolescent↗
PubMed1987

Surgery of incidental intracranial aneurysms.

A series of nine patients with an unruptured asymptomatic aneurysm not associated with a ruptured aneurysm is discussed. Three had giant aneurysms. Two patients had bilateral aneurysms of the middle cerebral artery. Five had solitary aneurysms of the middle cerebral artery. One had an aneurysm of the anterior communicating artery. One had an ophthalmic aneurysm. All aneurysms were clipped. Two operations were necessary in the two patients with bilateral aneurysms. There was no mortality and no significant morbidity. Clipping of the aneurysm is recommended for those patients who have no other serious illness that significantly increases the surgical risk. If a combination of pituitary tumor and aneurysm is found, a subfrontal instead of transsphenoidal approach should be considered so as to treat both the tumor and aneurysm at the same operation.

Cerebral Angiography↗
PubMed1983

Electron microscopic identification of trigeminal nerve fibers in the ciliary body and the iris.

The trigeminal nerve fibers in the ciliary body and the iris have been identified electron microscopically by using intra-axonally transported horseradish peroxidase injected into the trigeminal ganglion. The tracer revealed unmyelinated fiber profiles in the stroma of the ciliary body and the iris. These were not found to be associated with any particular organ but rather may terminate as free endings. Large profiles of varicosities contained mitochondria. Thin profiles, containing neurotubules, probably represent axons between the varicosities or endings. An interaction between the sensory and the autonomic peripheral fibers in the anterior uvea is suggested.

Animals↗
PubMed1979

Medullary emergency.

32 patients with symptoms and signs of medullary compression were submitted as emergencies to clinical and radiological examination in our hospital during a 5-year period. None of the patients was able to walk on admission. 27 emergency operations were performed to relieve medullary compression. If a single lesion in plain radiographs was well correlated with clinical symptoms and signs, the myelogram did not reveal crucial information. Young patients--aged 29 years or less--or patients with moderate symptoms on admission usually regained their ability to walk; as well as patients with a negative myelogram. On the other hand, old patients--aged 60 years or more--were only exceptionally able to walk later on. Other unfavourable signs were: a lesion of the thoracic spine, a total block in the myelogram, and a metastatic lesion. Our results of an emergency treatment were not better than the results of unhurried series reported in the literature.

Adolescent↗
PubMed1978

Movement-sensitive and direction and orientation-selective cutaneous receptive fields in the hand area of the post-central gyrus in monkeys.

1. In the hand area of the post-central gyrus of three alert Macaca speciosa monkeys neurones related to cutaneous receptors but not activated by simple touch on the receptive field were recorded using the transdural micro-electrode recording technique. Thirty-six cells were found to have complex cutaneous receptive field properties. These neurones were subdivided into the following three groups. 2. Nine neurones were not activated by punctate stimuli on the receptive fields but responded well to movement along the skin. The activity of these neurones was not affected by the direction of movement; nor was it sensitive to different textures of the moving surface. 3. Eighteen neurones responded to cutaneous movement along the skin surface in a particular direction giving no response to stimulation in the opposite direction and intermediate responses to intermediate directions. Similar responses were evoked from different subparts of the receptive field. 4. Nine neurones responded well to an edge placed on the skin in an optimal orientation or moved along the skin in a direction perpendicular to the edge. A maximal response was produced by stimuli of the same optimal orientation in different parts of the receptive field. The significance of the stimuli to the monkey had only a minor influence on the magnitude of the responses of these neurones and no influence on the receptive field properties. 5. The occurrence of the complex cutaneous cells increased from anterior to posterior within the post-central gyrus and most of them were found in Brodmann's area 2. Thus we postulate that the complex receptive field properties arise as a consequence of cortical processing in a network in which postsynaptic one-way lateral inhibition generates the directional properties of the neurones. 6. The complex cutaneous neurones constituted only 6% of the neurones studied in the hand area of the post-central gyrus. Thus the prevalence of neurones with elongated and direction-selective receptive fields is low in the primary somatosensory cortex in comparison with the visual cortex. These neurones may, however, serve the sterognostic capcity of the hand by contributing information about stimulus motion, orientation and direction of movement on the skin.

Animals↗
PubMed1978

Receptive field integration and submodality convergence in the hand area of the post-central gyrus of the alert monkey.

1. An exploration of the occurrence of different functional cell types was made in the three cytoarchitectural subdivisions (areas 3, 1 and 2) of the hand area of the post-central gyrus of the monkey. The functional properties of 632 cells were studied using the transdural micro-electrode recording method. 2. Over half of the neurones studied (57%) belonged to the class of simple skin neurones that were related either to rapidly adapting (272 neurones) or slowly adapting (seventeen neurones) cutaneous receptors or to both (seventy-one neurones). The simple skin neurones were particularly common in the anterior part of S I where they constituted 60% of the cells. More complicated cutaneous neurones made up 10% of the total sample. They were more common in the posterior part of the gyrus. 3. Altogether ninety-two neurones (15%) were related to subcutaneous or deeper receptors. Another seventy-one neurones (11%) exhibited convergence of skin input and input from deep receptors. A smaller group of forty-seven undamaged neurones (7%) were unrelated to stimuli of the types described above. 4. In tangential electrode penetrations made along the anterior and posterior banks of the gyrus, functional columns were found to be 500 micrometers wide on the average; this width is comparable with that of ocular dominance columns and visual orientation hypercolumns. 5. Correlation of the functional types of cells with cytoarchitecture showed that the complexity of the functional properties of the neurones increased posteriorly. The receptive field size also increased toward posterior. The changes that take place in the functional properties of cells when moving across different cytoarchitectural areas suggests intracortical information processing which leads to handling of larger body regions and more complex combinations of information in the cellular elements of the posterior part of the post-central gyrus.

Animals↗