PubMed Health⌕ Search

Biomedical subjects

R Danis

Publications and source records attributed to R Danis.

8 recordsLinked to original sources
PubMed2000

Gamma knife radiosurgery as a primary treatment for prolactinomas.

OBJECT: The purpose of this study was to estimate the efficacy of gamma knife radiosurgery (GKS) in controlling tumor growth and endocrinopathy associated with prolactinomas. METHODS: Between 1993 and 1997, 164 of 469 patients with pituitary adenomas treated by GKS harbored prolactinomas. The dose to the tumor margin ranged from 9 to 35 Gy (mean 31.2 Gy), and the visual pathways were exposed to a dose of less than 10 Gy. The mean tumor diameter was 13.4 mm. The mean follow-up time for 128 cases was 33.2 months (range 6-72 months). Tumor control was observed in all but two patients who underwent surgery 18 and 36 months, respectively, after GKS. Clinical cure was achieved in 67 cases. Clinical improvement was noted with a decrease in the hyperprolactinemia after GKS. Nonetheless, in 31 (29%) of 108 patients who were followed for more than 2 years no improvement in serum prolactin levels was demonstrated, although this could be normalized by bromocriptine administration after treatment. Nine infertile women became pregnant 2 to 13 months after GKS and all gave birth to normal children. There was no visual deterioration related to GKS. Five women experienced premature menopause. In these patients there was subtotal disappearance of the tumor and an empty sella developed. CONCLUSIONS: Gamma knife radiosurgery as a primary treatment for prolactinomas can be safe and effective both for controlling tumor growth and for normalization of prolactin hypersecretion. A higher margin dose (> or = 30 Gy) seemed to be associated with a better clinical outcome. Gamma knife radiosurgery may make prolactinomas more sensitive to the bromocriptine.

Humans↗
PubMed1996

Retinal blood flow during dynamic exercise.

BACKGROUND: Exercise acutely lowers intraocular pressure (IOP) and raises arterial pressure. We wondered whether the resultant increase in ocular perfusion pressure would alter retinal blood flow. METHODS: To investigate this question, 11 healthy volunteers each performed progressive cycle ergometer exercise until exhaustion was reached in 5-10 min. Immediately after exercise, retinal blood flow and arteriovenous passage time were determined by video fluorescein angiography. Ten other volunteers performed repeated episodes of cycle ergometer exercise at approximately 60% of the maximal aerobic capacity, immediately prior to estimates of macular leukocyte velocity and density via blue-field stimulation. RESULTS: Progressive exercise lowered IOP and elevated calculated ocular perfusion pressure. Within the retinal circulation, this exercise tended to raise mean dye velocity, as it significantly narrowed the superior temporal artery and vein; as a result, calculated retinal blood flow was unchanged. Simultaneously, retinal arteriovenous passage time was substantially shortened. Blue-field simulation showed that exercise increased macular leukocyte velocity while leaving leukocyte density unchanged. CONCLUSIONS: These results show that the normal retinal hemodynamic response to increases in perfusion pressure on dynamic exercise includes vasoconstriction that normalizes flow and faster capillary and overall retinal blood transit.

Adult↗
PubMed1996

Retinal blood flow indices in patients infected with human immunodeficiency virus.

AIMS/BACKGROUND: Abnormal blood flow dynamics are believed to contribute to the development of retinal microvascular disease in patients infected with human immunodeficiency virus (HIV). In this study, the scanning laser ophthalmoscope (SLO) was used, combined with fluorescein angiography, to measure retinal blood flow indices in HIV seropositive patients. METHODS: Arteriovenous passage time (AVP) and perifoveal capillary blood flow velocity (CFV) were measured in 23 HIV infected patients and 23 control subjects with SLO fluorescein angiography. RESULTS: No significant difference in AVP was found between the two groups. However, CFV was significantly reduced in HIV infected patients (p = 0.013). CONCLUSION: Patients infected with HIV show abnormal haemodynamics at the level of the perifoveal capillaries.

Adult↗
PubMed1986

Sodium homeostasis in infants with biliary drainage procedures.

We studied biliary excretion of sodium and chloride in 17 infants with external bile drainage through a "biliostomy" and describe four additional children who became ill from sodium depletion following external biliary drainage procedures for biliary tract anomalies. In the 17 infants, the mean +/- SD bile sodium concentration was 122 +/- 15 mEq/L. The mean +/- SD serum sodium concentration was low (132 +/- 7 mEq/L) (normal, 138 to 145 mEq/L). The mean +/- SD bile volume was 388 +/- 317 mL/day at one year following surgery (range, 40 to 1,000 mL/day). In the four children, clinical manifestations of sodium depletion (lethargy, anorexia, dehydration, and malnutrition) necessitated hospital admission. At that time, the serum sodium concentration ranged from 109 to 129 mEq/L, and the simultaneous urinary sodium concentration ranged from 0 to 5 mEq/L. Although dietary sodium was normal, biliary losses exceeded dietary intake, resulting in salt and water depletion despite renal conservation. Children with biliary drainage procedures are at risk for sodium depletion and should be monitored closely and supplemented accordingly until biliostomy closure is performed.

Bile↗
PubMed1984

Optic atrophy and the Wyburn-Mason syndrome.

A 14-year-old girl developed impaired vision and optic atrophy of the left eye as a manifestation of an orbital and parachiasmal arteriovenous malformation. Despite the lack of a retinal arteriovenous malformation, this condition appears to be a variant of the Wyburn -Mason syndrome, representing a vascular dysgenesis of the orbit and midbrain resulting in focal arteriovenous communications without interposed capillaries.

Adolescent↗