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Biomedical subjects

R Dias

Publications and source records attributed to R Dias.

At least 37 records · Page 2Linked to original sources
PubMed1997

Scrotal fixation: a different surgical approach in the management of the low undescended testes.

OBJECTIVES: To evaluate the feasibility of using the scrotal approach in patients with undescended testes. METHODS: Over an 18-month period, 165 patients were diagnosed to have 208 undescended testes. Of these, 28 were nonpalpable. RESULTS: At exploration, 7 testes were abdominal, 33 were canalicular, 165 were in the region of the external ring/pubic tubercle, and 1 was perineal. There were 2 cases of unilateral monorchism. The operative procedure performed was as follows: orchiectomy for 6 abnormal testes, orchiopexy for 142, and scrotal fixation (SF) for 58. (In this series, 9 patients were converted from SF to an orchiopexy at the time of the initial operative procedure.) SF involves a scrotal incision extending down to the tunica vaginalus. The cord is then mobilized from below, after which the testis is placed in an extra-dartos pouch. CONCLUSIONS: Our study has shown that there are a significant number of undescended testes that lie in the region of the pubic tubercle, lack a hernial sac, and can be managed by a scrotal mobilization alone. Based on our experience with SF, we have used a simple classification of undescended testis that has therapeutic and prognostic justifications.

Child↗
PubMed1997

Contrasting effects of excitotoxic lesions of the prefrontal cortex on the behavioural response to D-amphetamine and presynaptic and postsynaptic measures of striatal dopamine function in monkeys.

The effects of excitotoxic lesions of the prefrontal cortex on behavioural, neurochemical and molecular indices of dopamine function in the caudate nucleus were studied in the marmoset. The lesion, which encompassed both the lateral and orbital regions of prefrontal cortex, made the animals more sensitive to the performance disrupting effects of the dopamine releasing drug, D-amphetamine, in a variation of the object retrieval task. Specifically, following drug administration, the lesioned marmosets were less able to gain access to food reward in the minimum number of responses. Analysis of the nature of the errors suggested that the deficit was not due to inhibition of a prepotent response as the lesioned monkeys were just as likely to make a detour reach to the unopened side of the box as a direct "line-of-sight" reach into the unopened front of the box. Rather, the data indicated a general disorganization of behaviour. The enhanced behavioural responsiveness to manipulations increasing presynaptic dopamine function was accompanied by neurochemical changes indicating a reduced responsiveness, as revealed by in vivo microdialysis. Thus, in lesioned animals, whilst there were no effects on baseline levels of extracellular dopamine in dorsolateral caudate, evoked release, both to systemic D-amphetamine and to a local depolarizing pulse of potassium ions, was attenuated. These opposite effects of the prefrontal cortex lesion on behavioural and neurochemical indices of striatal dopamine function occurred in the absence of any changes in striatal dopamine receptors of the D1 and D2 subtype, as determined both by radioligand binding assays and measurements of messenger RNA using in situ hydridization techniques. These data provide further insight into the interactions between prefrontal cortex and striatal dopamine function in the non-human primate. In particular, when taken in the light of our previous studies they indicate that following prefrontal manipulations, concurrence between behavioural and neurochemical indices of striatal dopamine function depends, critically, on the behavioural task. These findings are discussed with respect to the growing body of evidence implicating abnormalities in frontostriatal neurotransmission in complex disorders such as schizophrenia.

Analysis of Variance↗
PubMed1996

Dissociation in prefrontal cortex of affective and attentional shifts.

The prefrontal cortex is implicated in such human characteristics as volition, planning, abstract reasoning and affect. Frontal-lobe damage can cause disinhibition such that the behaviour of a subject is guided by previously acquired responses that are inappropriate to the current situation. Here we demonstrate that disinhibition, or a loss of inhibitory control, can be selective for particular cognitive functions and that different regions of the prefrontal cortex provide inhibitory control in different aspects of cognitive processing. Thus, whereas damage to the lateral prefrontal cortex (Brodmann's area 9) in monkeys causes a loss of inhibitory control in attentional selection, damage to the orbito-frontal cortex in monkeys causes a loss of inhibitory control in 'affective' processing, thereby impairing the ability to alter behaviour in response to fluctuations in the emotional significance of stimuli. These findings not only support the view that the prefrontal cortex has multiple functions, but also provide evidence for the distribution of different cognitive functions within specific regions of prefrontal cortex.

Affect↗
PubMed1996

Primate analogue of the Wisconsin Card Sorting Test: effects of excitotoxic lesions of the prefrontal cortex in the marmoset.

Using a primate analogue of the Wisconsin Card Sort Test, this study demonstrated, for the first time, that lesions of the prefrontal cortex in monkeys produce a qualitatively similar impairment in attentional set-shifting to that seen following prefrontal cortical damage in humans. Although damage to the prefrontal cortex did not disrupt the ability of marmosets, a New World monkey, to maintain an attentional set, it did disrupt their ability to shift an attentional set. It also impaired their performance on discrimination reversal, object retrieval, and spatial delayed response, consistent with the effects of prefrontal damage in Old World monkeys. Comparison of the cognitive processes underlying discrimination reversal, object retrieval, and attentional set-shifting reveals the various types of inhibitory control provided by the prefrontal cortex.

Animals↗
PubMed1986

Hypothalamic proline endopeptidase activity is not changed by various behavioral procedures.

Proline endopeptidase (E.C.3.4.21.26) is an enzyme which cleaves several neuropeptides at the carboxyl-side of proline residues. Some peptide substrates of this enzyme may be found in the rat hypothalamus (thyrotropin releasing hormone, neurotensin, substance P, oxytocin, vasopressin, beta-endorphin). Recent research has shown that the hypothalamic levels of some of these substances (e.g., vasopressin, beta-endorphin) change by a variety of training procedures. We studied the effect of various forms of training on the activity of proline endopeptidase of rat hypothalamus. The present results show that the activity of this enzyme is not altered by electroconvulsive shock or inhibitory avoidance training when measured, 0, 1, or 3 hr after these procedures. Other behavioral procedures (habituation to an open field, two-way active avoidance conditioning, or 1 min of inescapable footshock) also had no effect on hypothalamic proline endopeptidase activity measured immediately after training or test sessions. We conclude that proline endopeptidase probably does not play a regulatory role in the effect of synaptically released hypothalamic neuropeptides on behavior.

Animals↗
PubMed1979

Multilocular cystic disease of kidney.

A case of multilocular cyst of the kidney with calcification is presented and pertinent literature is reviewed. With our present knowledge, a multilocular cyst cannot be clearly differentiated from a malignant renal tumor by preoperative evaluation. Conservative surgery with operative evaluation of the lesion is suggested.

Adenocarcinoma↗
PubMed1979

Amyloidosis of renal pelvis and urinary bladder.

We describe a patient with amyloidosis of renal pelvis and 2 patients with urinary bladder amyloidosis. Clinical presentation in all of the cases mimicked cancer of the respective sites. Clinical diagnosis of amyloidosis is not possible, making biopsy mandatory. Immunology of amyloid formation and treatment of amyloidosis are discussed.

Aged↗
PubMed1978

Aids in diagnosis of suspect ectopic ureters in female patients.

When suspected ectopic ureters cannot be visualized by conventional methods, such as excretory urogram, nephrotomograms, or by intravenous indigo carmine, then direct injection of vaginal, suburethral, or paraurethral "swellings," which are in effect dilated terminal ureters, may confirm the diagnosis.

Catheterization↗
PubMed1978

Malignant fibrous histiocytoma of spermatic cord.

Malignant fibrous histiocytomas are very rare, particularly those related to urogenital organs. We report herein the third known case of this entity involving the spermatic cord. Summary of the previously reported 2 cases is given with recent follow-up. Prognosis is poor.

Aged↗
PubMed1977

Iatrogenic renal artery thrombosis.

Renal calculi were removed from 2 women--in 1 case by renal bisection and in the other by nephrolithotomy. In each case a small bulldog clamp was applied to the renal artery for less than 30 minutes. Both patients suffered renal artery thrombosis necessitating nephrectomy. When the histories of these patients were reviewed the common factor found was oral contraceptives, suggesting that oral contraceptives may predispose to renal artery thrombosis.

Adult↗
PubMedDate not supplied

Aerobic bacteria, Chlamydia trachomatis, Pneumocystis carinii and Cytomegalovirus as agents of severe pneumonia in small infants.

The authors studied 58 infants hospitalized for pneumonia in a semi-intensive care unit. Age ranged from 1 complete to 6 incomplete months. The infants were sent from another hospital in 20 cases and from home in a further 38. Pulmonary involvement, which was alveolar in 46 cases and interstitial in 12, was bilateral in 31 children. The investigation was carried out prospectively on the etiological agents associated with respiratory infection to look for evidence of aerobic bacteria (blood cultures), Chlamydia trachomatis and Cytomegalovirus (serology), and Pneumocystis carinii (direct microscopy of tracheal aspirated material). The following infectious agents were diagnosed in 21 children (36.2%): Aerobic bacteria (8), Chlamydia trachomatis (5), Pneumocystis carinii (3), Cytomegalovirus (3), Cytomegalovirus and Chlamydia trachomatis (1), Aerobic bacteria and Cytomegalovirus (1). Seven cases of infection by Chlamydia trachomatis and/or Cytomegalovirus were diagnosed out of the 12 cases with pulmonary interstitial involvement.

Age Factors↗