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Biomedical subjects

H M Brink

Publications and source records attributed to H M Brink.

9 recordsLinked to original sources

Punctal and canalicular stenosis associated with systemic fluorouracil therapy. Report of five cases and review of the literature.

Ocular side effects of systemic fluorouracil include excessive lacrimation, due to punctal and canalicular stenosis and fibrosis. Obstruction of the tear ducts after systemic therapy with fluorouracil is more frequent than is assumed. Five patients with breast cancer and punctal or canalicular stenosis are presented. Although complaints of epiphora usually resolve two weeks after cessation of systemic therapy, local antibiotics and steroids may be indicated. In patients with persisting complaints, and patients treated with fluorouracil for a prolonged period of time, prophylactic intubation of the tear ducts with silastic tubes has been advocated. (Conjunctivo)dacryocystorhinostomy may be unavoidable.

Aged↗

[Chronic recurrent polychondritis].

In a 71-year-old woman suffering from recurrent fever, dry cough, pain during sighing, hoarseness and later severe inflammation of the cartilage of both auricles 'relapsing polychondritis' was diagnosed. This is a rare disease of cartilage and connective tissue. Most frequent symptoms are inflammation of the auricles and nasal septum, joint disorders and inflammation of eye structures, larynx and trachea. The aetiology may be autoimmunity. The clinical diagnosis can be confirmed by a cartilage biopsy. The disease is recurrent and causes substantial morbidity and mortality. Therapy consists of NSAIDs, steroids, and sometimes immunosuppressive agents.

Aged↗

Uveal melanomas diagnosed in the 6 months after lens-implant surgery.

During a five-year period uveal melanoma was diagnosed in 11 patients in the 6 months after lens-implant surgery. Pre-operatively all but one of the patients had bilateral senile cataract. The tumours were remarkably large and localised in the periphery rather than in the posterior pole (mean maximum tumour diameter 12.5 mm); they were therefore present at the time of surgery. An adequate pre-operative diagnostic ultrasound examination had not been performed in any of the patients. A plea is therefore made for the performance of an echographic examination in all eyes with opaque media in order to exclude solid lesions or other pathology in the vitreous cavity.

Aged↗

The electro-oculogram in uveal melanoma. A prospective study.

The electro-oculogram in 52 patients with a suspected malignant melanoma of the choroid or ciliary body was plotted in a diagram constructed for the differential diagnosis of malignant melanoma, metastasis, naevus and retinal detachment. Thirty-one patients were diagnosed as suffering from malignant melanoma on clinical grounds (19 histologically confirmed). Twenty-six were classified correctly as a melanoma using our EOG probability score. Rupture of Bruch's membrane and tumor localization were of no influence on the EOG classification. Accompanying retinal detachment lowered the Lp/Dt-ratio significantly without affecting the Dt, as was also the case in tumors with a prominence equal to or greater than 6 mm when compared with smaller tumors. However melanomas were still classified correctly in the majority of the patients by means of EOG. We conclude that an acceptable differentiation can be made between melanomas, retinal detachments and naevi. Melanomas cannot be differentiated from choroidal metastases.

Choroid Neoplasms↗

Radiotherapy of choroidal metastases.

With binocular indirect ophthalmoscopy, fluorescin angiography and ultrasonography 68 choroidal metastases in 52 eyes of 39 patients were diagnosed. The primary tumors were mainly breast cancer (81%) and lung cancer (10%). After radiation treatment the visual acuity improved in 17 eyes (38%), stabilized in 15 eyes (33%), whereas in 13 eyes (29%) deterioration could not be prevented (seven eyes unknown). Regression of the lesions or its accompanying secondary retinal detachment was seen in 78% of the eyes treated. Acute transient side effects of radiation therapy were kerato-conjunctivitis (nine patients) and acute glaucoma in one patient. No cataractous changes of the lens were observed in the post radiation period (one to 42 months). Irradiation of choroidal metastases can contribute to improvement of the quality of life with a treatment scheme of 30 Gy in ten daily fractions.

Adolescent↗

Glomerular filtration in the isolated perfused kidney. I. Sieving of macromolecules.

The permeability of the glomerular capillary wall to neutral macromolecules was studied in isolated perfused rat kidneys. Pluronic F108 (BASF, Wyandotte, MI, USA), a polyoxyethylene-polyoxypropylene block copolymer of mol weight approximately 14,000, was used as plasma expander. Pore theory was applied to the fractional clearances of Pluronic F108 and dextran (mol weight 19,400) molecules measured both as a function of glomerular filtration rate. Using the pore model of Verniory et al. [30] the effective pore radius (60.9 A) and the ratio of total pore area and pore length (4.0 cm/nephron) were estimated, and a hydraulic permeability coefficient KF (0.036 nl/s . mm Hg) was calculated. There was no significant difference between the fractional clearance of Pluronic F108 obtained with different Pluronic F108 concentrations over the range 15-35 g/l, hence with largely differing osmotic pressures. It was concluded that the sieving properties of the glomerular membrane of the isolated perfused rat kidney are not detectably different from those in the intact rat, at least in the case of uncharged macromolecules.

Animals↗

Glomerular filtration in the isolated perfused kidney. II. Glomerular hemodynamics.

Glomerular hemodynamics were studied of isolated perfused kidneys of 12-wk-old normotensive (NR) and spontaneously hypertensive (SHR) rats, using Pluronic F108 (BASF, Wyandotte, MI, USA) as a plasma expander. Glomerular filtration rate (GFR), proximal tubular hydrostatic pressure (PT) and glomerular capillary hydrostatic pressure (PGC) were approximately linearly related with renal perfusion pressure. PGC measured directly by micropuncture was comparable to PGC calculated from other parameters of glomerular dynamics using pore theory. We conclude that GFR in isolated kidneys perfused with Pluronic F108 is lower than in vivo, mainly as a result of an increase in PT. This rise in tubular pressure is due to an increased urine flow rate and an elevated tubular fluid viscosity. The difference in glomerular dynamics between NR and SHR kidneys is the result of an increased preglomerular vascular resistance in SHR, possibly due to an adaptive hypertrophic reaction to a sustained hypertension.

Animals↗

Instantaneous measurement of glomerular filtration rate in the isolated perfused rat kidney.

In perfusion studies on the isolated cellfree perfused rat kidney, the glomerular filtration rate (GFR) can be controlled if the GFR can be measured instantaneously. This paper reports on a GFR meter which opens this possibility. Vitamin B12 is used as a marker for the GFR. A bubble flow meter determines urine flow rates ranging from 10 up to 200 microliter-min-1. A fiberoptic colorimeter measures vitamin B12 concentrations in the urine up to 400 mg-l-1. The flow meter and the colorimeter are described in detail. The reliability of vitamin B12 as a marker for the GFR is demonstrated and, moreover, the identity of GFR values obtained with the GFR meter and those from B12 spectrophotometry is demonstrated.

Animals↗