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Biomedical subjects

H Beekhuis

Publications and source records attributed to H Beekhuis.

At least 19 recordsLinked to original sources
PubMed2001

Amniotic membrane transplantation in the management of conjunctival malignant melanoma and primary acquired melanosis with atypia.

AIM: To evaluate the efficacy of amniotic membrane transplantation (AMT) for the management of conjunctival malignant melanoma and primary acquired melanosis (PAM) with atypia. METHODS: Four consecutive patients with histologically proved invasive, primary conjunctival malignant melanoma were treated with wide surgical excision and AMT. Amniotic membrane grafts were harvested and processed under sterile conditions according to a standard protocol. The grafts were sutured to the margins of the surface defect. In one case, AMT was combined with a corneoscleral graft. RESULTS: A satisfactory result and rapid postoperative recovery with few, transient side effects was noted in three patients with limbal/epibulbar melanomas. In another patient with an extensive lesion, involving the epibulbar, forniceal, and palpebral conjunctiva, AMT following wide excision was complicated by symblepharon formation and restricted ocular motility. Monitoring of local recurrence was facilitated by the transparency of the thin graft in all cases. The postoperative follow up time varied between several months and 3 years. In one case, local recurrence of PAM was observed and treated using topical mitomycin. CONCLUSIONS: AMT is a useful technique for the reconstruction of both small and large surface defects that result from the surgical excision of conjunctival malignant melanoma and PAM. This method facilitates wide conjunctivectomy, although its role in repairing larger defects involving the fornix or palpebral conjunctiva still needs to be established. The transparency of amniotic membrane allows for monitoring of tumour recurrence, which is-together with superior cosmesis-an advantage over thicker (for example, buccal) mucous membrane grafts.

Administration, Topical↗
PubMed2000

Tissue damage after single high-dose intraoperative irradiation of the canine liver: evaluation in time by means of radionuclide imaging and light microscopy.

To establish the tolerance of liver tissue to single high-dose intraoperative irradiation, the histopathological changes in the canine liver after single high-dose intraoperative irradiation were investigated by means of radionuclide imaging and light microscopy. Intraoperative irradiation at doses of 0, 10, 20, 25 or 30 Gy was applied to a part of the liver of 25 beagles. Radionuclide imaging using (99m)Tc-sulfur colloid was performed at several times during follow-up. Elective humane killing was done 3 months and 1, 2, 3 and 5 years after irradiation. Light microscopy was used to identify histopathological alterations. There was no morbidity or mortality during a maximal follow-up of 5 years. In 40% of the animals, a region of diminished uptake was observed at the irradiation site. The regions of diminished uptake of the radiopharmaceutical agent became smaller with time. Light microscopic examination revealed severe parenchymal fibrosis, liver cell atrophy, and bile duct proliferation at the irradiated area 1 to 2 years after irradiation. At 3 and 5 years, vascular changes with endothelial proliferation and focal arteriolar hyalinosis were observed. This study demonstrates that intraoperative irradiation of a part of the liver in the canine model can be applied safely. Light microscopy confirmed that histological damage was not always accompanied by diminished uptake of the radiopharmaceutical agent at the irradiation site.

Animals↗
PubMed1996

Fc-receptor function after human splenic autotransplantation.

Mononuclear phagocytic function was studied using the Fc-receptor test in 24 patients who underwent splenectomy, ten of whom underwent splenic autotransplantation. All patients undergoing autotransplantation had mononuclear phagocyte system (MPS) activity at the transplantation sites. In eight of the 14 patients who did not undergo autotransplantation there was also scintigraphic MPS activity indicative of ectopic splenic tissue. Although the Fc-receptor test showed delayed and monoexponential blood clearance in all patients after splenectomy, there were no significant differences between the patient groups. Autotransplantation of small amounts of splenic tissue after splenectomy provides some MPS activity but is inadequate for blood clearance.

Adolescent↗
PubMed1996

Angiotensin-converting enzyme inhibition-induced changes in hippurate renography and renal function in renovascular hypertension.

UNLABELLED: We studied the mechanism of angiotensin-converting enzyme (ACE) inhibition-induced changes in hippurate renography of the poststenotic kidney. METHODS: Ten male mongrel dogs, six with unilateral and four with bilateral renal artery stenosis, were equipped with renal artery blood flow probes and catheters in the aorta, atrium and both renal veins. RESULTS: Enalaprilat (10 mg intravenously) in conscious dogs with renal artery stenoses produced changes in all stenotic (n = 11) but not in nonstenotic kidney 123I-hippurate renograms (n = 6). Renographic changes correlated significantly with initiation of intrarenal 131I-hippurate retention, a decrease in mean arterial pressure (MAP), renal extraction of 131I-hippurate and 125I-iothalamate (r = 0.68, r = 0.62, r = 0.84, r = 0.83, respectively) but not with renal blood flow changes (r = 0.34). Furthermore, renal uptake of 131I-hippurate and 125I-iothalamate decreased in stenotic kidneys with a grade II renogram (-52 +/- 11% and -79 +/- 6%, respectively). Iodine-125-hippurate autoradiograms of stenotic kidneys during ACE inhibition showed tracer retention mainly in the proximal tubular cells. Results during osmotic diuresis supported our findings. CONCLUSION: Angiotensin-converting enzyme inhibition-induced hippurate retention curves of poststenotic kidneys appear to result from a sequence of events. A decrease in MAP combined with efferent vasodilation leads to a decrease in intraglomerular capillary pressure. This decrease in pressure causes a decrease in glomerular filtration rate and proximal tubular urine flow. This decrease in turn hampers tubular hippurate transit and transport across the luminal membrane, leading to intrarenal hippurate retention and, in more severe cases, decreased renal hippurate uptake.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1995

Iodine-131 Hippuran for the estimation of renal plasma flow: requirements for radiochemical purity.

For many years iodide-131 Hippuran has been used as a tracer to measure effective renal plasma flow (ERPF). Because of the low renal clearance of free 131I-iodide and the inability to count it separately from 131I-Hippuran, free 131I-iodide will lower the calculated 131I-Hippuran clearance, resulting in a lower estimated ER-PF. This study was performed to establish the maximum allowable radiochemical impurity of free 131I-iodide in 131I-Hippuran preparations for ERPF measurements in continuous clearance studies. A known amount of 123I-iodide was added to the (131I-iodide-free) 131I-Hippuran solution used for continuous infusion clearance studies in nine patients. 123I-iodide activity was used because it can be counted separately from 131I-Hippuran in the infusion solutions and plasma samples while it behaves exactly like 131I-iodide, so that the results obtained with 123I-iodide can be extrapolated to 131I-iodide. After performing the clearance studies, the ERPF was calculated firstly with 131I-Hippuran activity only (= true ERPF) and secondly including the free radioactive iodide activity (= false ERPF) in the clearance formula. As expected, if free 131I-iodide is present in the infusion solution, its concentration in plasma will be highest at the end of the clearance study. The 131I-iodide concentration in plasma relative to the 131I-Hippuran concentration will be higher in patients with high ERPF values.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1995

Noninvasive measurement of intrarenal blood flow distribution: kinetic model of renal 123I-hippuran handling.

A new technique for noninvasive measurement of intrarenal blood flow distribution over cortex and medulla is proposed. The technique involves analysis of 123I-labeled hippuran renography, according to a kinetic model that describes the flow of 123I-hippuran from the heart (input) through the renal cortex and medulla to the bladder (output). The method is validated and compared with the standard microsphere injection technique in anesthetized dogs. Changes in intrarenal blood flow distribution were induced by infusion of placebo (n = 6), angiotensin I (n = 5), or atrial natriuretic factor (n = 5). Baseline percentage medullary blood flow in the left kidney was 12 +/- 1% of total renal blood flow measured with microspheres and 15 +/- 1% with renography. During infusion of the placebo, medullary blood flow decreased slightly compared with baseline, as measured with both methods, by 2 +/- 6 (microspheres) and 1 +/- 8% (renography). Infusion of angiotensin I caused a marked fall in medullary blood flow by 42 +/- 11 (microspheres) and 57 +/- 8% (renography). In contrast, infusion of atrial natriuretic factor caused a small rise in medullary blood flow as measured with both methods (9 +/- 3 and 12 +/- 11%, respectively). The absolute and percent changes in medullary blood flow measured with renography correlated with those measured with microspheres (left kidney: r = 0.67, P = 0.005; r = 0.71, P = 0.003, respectively; right kidney: r = 0.62, P = 0.01; r = 0.68, P = 0.004, respectively). We conclude that the proposed kinetic model of renal 123I-hippuran handling can be used to measure changes in intrarenal blood flow distribution and, because of its noninvasive character, may be of use in clinical studies.

Angiotensin I↗
PubMed1995

Esophageal hypomotility in primary and secondary Raynaud's phenomenon: comparison of esophageal scintigraphy with manometry.

UNLABELLED: Esophageal motility was assessed by manometry and scintigraphy in 25 patients with primary Raynaud's phenomenon and 24 patients with secondary Raynaud's phenomenon as part of a connective tissue disorder. METHODS: For each scintigraphic study, transit time was evaluated after three separate swallows. Scintigraphy was abnormal if transit time was longer than 15 sec for two or three measurements. RESULTS: In the case of primary Raynaud's phenomenon, manometry was normal in 24 of 25 patients. A similar ratio was found with scintigraphy. In the case of secondary Raynaud's phenomenon manometry was abnormal in 15 of 24 patients, while scintigraphy was abnormal in 13 of 24 patients. Considering manometry as gold standard, overall sensitivity of scintigraphy was 86%, specificity 89%, positive predictive value 75% and negative predictive value 94%. CONCLUSION: Esophageal dysfunction is common in patients with connective tissue disorders but rare in patients with primary Raynaud's phenomenon. Esophageal scintigraphy is a useful noninvasive initial screening test for esophageal dysfunction in patients with Raynaud's phenomenon.

Adolescent↗
PubMed1994

Role of vagal dysfunction in motility and transit disorders of jejunal Roux limb after Roux-en-Y gastrojejunostomy.

After a Roux-en-Y gastrojejunostomy patients frequently complain about abdominal pain, fullness, nausea and vomiting, ie, the Roux-en-Y syndrome. Stasis in the Roux limb due to disordered motility is known to be a cause of these complaints. The aim of the present study was to determine whether vagal denervation contributes to the development of motility disturbances and stasis in the Roux limb. Forty-seven patients with a Roux-en-Y gastrojejunostomy after partial gastrectomy were studied. A truncal vagotomy had been performed in 26 of these 47 patients. Transit through the Roux limb was evaluated by radionuclide studies, motility in the Roux limb was studied by manometry, and vagal function was tested by measuring the pancreatic polypeptide response to an insulin-induced hypoglycemia (PP test). On the basis of the PP test patients were classified as having (1) normal, (2) moderately impaired, and (3) severely impaired vagal function. The PP test showed that two of the 26 patients subjected to vagotomy had a moderately impaired vagal function, the other 24 all had a severely impaired vagal function. In the patients not subjected to a vagotomy, vagal function was disturbed in 11 of the 21 patients. Motility disturbances were not observed more frequently in patients with either moderately or severely impaired vagal function than in patients with normal vagal function. Stasis in the Roux limb was seen even more frequently in patients with a normal vagal function than in patients with a severely impaired vagal function.(ABSTRACT TRUNCATED AT 250 WORDS)

Anastomosis, Roux-en-Y↗
PubMed1993

Transit disorders of the gastric remnant and Roux limb after Roux-en-Y gastrojejunostomy: relation to symptomatology and vagotomy.

Patients after Roux-en-Y gastrojejunostomy frequently complain of upper abdominal pain, fullness, nausea and vomiting. This study was performed to clarify the relationship of this Roux-en-Y syndrome to transit disorders in the gastric remnant and Roux limb, and to vagal status. Using a questionnaire, 35 of 66 patients operated on between 1976 and 1987 were judged to suffer from the Roux syndrome. Gastrojejunal transit was studied by scintigraphy with a solid test meal in 61 patients, 34 of whom were symptomatic. The median (interquartile range) gastric half-emptying time was longer in symptomatic than in asymptomatic patients (79 (43-146) versus 56 (27-79) min, P < 0.05), and in patients with a bilateral vagotomy than in those without a vagotomy (94 (43-225) versus 59 (31-77) min, P < 0.05). Stasis in the Roux limb was observed in 18 of 28 symptomatic and in only three of 27 asymptomatic patients (P < 0.01). The median (interquartile range) fraction of activity emptied from the stomach and remaining in the Roux limb at 60 min was 54 (39-60) per cent in symptomatic patients and 33 (21-40) per cent in those without symptoms (P < 0.01). Stasis in the Roux limb was not related to vagal status. No relationship between slow gastric emptying and Roux-limb stasis was found. Slow gastric emptying, Roux-limb stasis or a combination of both was found in 30 of 34 symptomatic and in only nine of 27 asymptomatic patients (P < 0.01). It is concluded that both slow gastric emptying and Roux-limb stasis can be interpreted as causing the Roux syndrome. Vagotomy seems to be the major cause of slow gastric emptying, but it is not related to stasis in the Roux limb.

Adult↗
PubMed1993

Manometric and scintigraphic studies of the relation between motility disturbances in the Roux limb and the Roux-en-Y syndrome.

After a Roux-en-Y gastrojejunostomy, patients frequently complain of abdominal pain, fullness, nausea, and vomiting. This so-called Roux-en-Y syndrome is caused by slow gastric emptying, Roux-limb stasis, or both. The pathogenesis of these transit disorders is unknown. The aim of the present study was to investigate whether slow gastric emptying and Roux-limb stasis can be attributed to motility disturbances in the Roux limb. Thirty-seven patients with a Roux-en-Y gastrojejunostomy after partial gastrectomy were studied, 26 of whom had the Roux-en-Y syndrome and 11 who did not. Gastrojejunal transit was evaluated by radionuclide studies, and motility in the Roux limb was studied by manometry. Thirteen patients had slow gastric emptying, and 14 had stasis in the Roux limb. Slow gastric emptying, Roux-limb stasis, or a combination of both was found in 20 of 26 symptomatic patients and in only 4 of 11 asymptomatic patients (p < 0.05). The basic motor patterns, the interdigestive motor cycle, and the fed state were present in most patients. However, motility disturbances were present in 34 of the 37 patients. Motility disturbances were observed significantly more frequently in patients with symptoms than in those without, and also in patients with Roux-limb stasis than in those without, but no relation was found between motility disorders and slow gastric emptying. Aberrant propagation of the migrating motor complex and the absence of the fed state were the only motility disorders that were not observed in patients with normal Roux-limb transit. Of the various recorded motility disturbances, these two probably represent the more serious motility disturbances. The results of our study indicate that Roux-limb stasis is caused by motility disorders in the Roux limb. They also indicate that Roux-limb stasis is not responsible for slow gastric emptying, since there is no correlation between motility disorders in the Roux limb and slow gastric emptying.

Abdominal Pain↗
PubMed1993

Changes in refraction after retinal detachment surgery corrected by extended wear contact lenses for early visual rehabilitation.

The encircling band used in conventional retinal detachment surgery creates a circular indentation of the eye and thus may increase the anterior-posterior axial length. The myopia induced by encircling elements in retinal detachment surgery varies between 0 and 3 D. In a series of 25 patients, the average change in refraction after surgery was -2.25 D. To achieve early visual rehabilitation, patients were fitted with extended-wear soft contact lenses 7 to 10 days after surgery. The patients were followed for up to 6 months and contact lenses were exchanged according to changes in refraction. Visual rehabilitation using extended-wear lenses was immediate and excellent. The contact lenses were tolerated well. Two patients developed a minor corneal infiltrate under the soft lens and were withdrawn from the study.

Adult↗
PubMed1993

Distribution of exogenous surfactant in rabbits with severe respiratory failure: the effect of volume.

The transient effect of surfactant therapy that is observed in some patients might, at least in part, be explained by a nonhomogeneous distribution. Therefore, we investigated the distribution of a surfactant preparation (Alvofact, 45 g/L) that is used clinically. Rabbits with severe respiratory failure were treated with this surfactant at a dose of 100 mg/kg body weight, and the distribution of surfactant was determined by the use of 141Ce-labeled microspheres that were mixed with the surfactant. Fifteen min after surfactant administration, the rabbits were killed, and the lungs were removed and divided into 200 pieces. The radioactivity per mg lung tissue was determined in each piece. We found that the endotracheal instillation of this surfactant preparation results in a nonhomogeneous distribution. However, a significantly improved distribution was obtained when this dose of surfactant (100 mg/kg body weight) was diluted with normal saline to a concentration of 6.25 g/L. The consequence of the administration of this dose was an intratracheal fluid administration of 16.0 mL/kg body weight. The distribution was also nonhomogeneous after the administration of a small-volume (2.4 mL/kg body weight), low-concentration surfactant preparation (6.25 g/L). We conclude that a surfactant preparation with clinical application is distributed nonhomogeneously in the lungs after endotracheal administration. The distribution can be significantly improved by increasing the fluid volume in which the surfactant is suspended.

Animals↗
PubMed1992

Changes in renal function induced by ACE-inhibition in the conscious two-kidney, one-clip Goldblatt hypertensive dog.

In order to study why the diagnostic sensitivity of 123I-hippurate renography for a renal artery stenosis is improved by angiotensin converting enzyme (ACE-) inhibition we used the model of the conscious chronically instrumented two-kidney, one-clip Goldblatt hypertensive dog. Urine flow (UV), renal blood flow (RBF), glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were measured (with constant infusion of 125I-iothalamate and 131I-hippurate, respectively) for both kidneys separately before and after a bolus injection of a mild unilateral renal artery stenosis (approximately 30% reduction of RBF). During ACE-inhibition, there were remarkable falls in poststenotic GFR (from 37 +/- 5 to 4 +/- 2 ml/min, p less than 0.05), ERPF (from 111 +/- 13 to 21 +/- 10 ml/min, p less than 0.05) and UV (from 0.86 +/- 0.15 to 0.075 +/- 0.045 ml/min, p less than 0.05), whereas RBF of the poststenotic kidney slightly increased (from 193 +/- 18 to 237 +/- 27 ml/min, p less than 0.05). The concentration of hippurate and thalamate in the blood remained remarkably constant while the excretion of the tracers by the poststenotic kidney diminished and renal retention of 123I-hippurate was seen on the renogram. In 2 dogs, the experiments were repeated during mannitol infusion. In that situation, there was a much smaller decrease of poststenotic UV and GFR whereas ERPF even showed a small increase comparable to the RBF changes.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1991

Cisapride in treatment of Roux-en-Y syndrome.

UNLABELLED: After Roux-en-Y gastrojejunostomy patients frequently complain of upper abdominal pain, fullness, nausea, and vomiting. This Roux-en-Y syndrome is caused by slow gastric emptying, Roux-limb stasis, or both. Treatment of this syndrome is cumbersome. We evaluated the effect of cisapride on complaints and on transit through gastric remnant and Roux limb in 24 such patients. Thirteen of them had slow gastric emptying and 13 had stasis in the Roux limb (two patients had both). Symptoms and transit were evaluated before and after three weeks of treatment using a questionnaire and scintigraphy. Responding subjects continued therapy and were interviewed again after six months. Seven patients with slow gastric emptying and three patients with Roux-limb stasis had enduring symptomatic relief; all exhibited accelerated transit during therapy: mean half gastric emptying time in the seven patients with slow gastric emptying was 204 +/- 89 min before and 111 +/- 59 min during cisapride (P less than 0.05); mean percentage of radioactivity, emptied from the gastric remnant, which remained in the Roux limb at 60 min in the three patients with Roux limb stasis was 74 +/- 4% before and 25 +/- 10% during cisapride (P less than 0.05). In patients without symptomatic response, transit did not improve. CONCLUSION: with cisapride long-lasting symptomatic relief and improved transit is achieved in about 40% of patients with the Roux-en-Y syndrome.

Adult↗
PubMed1991

The mechanism and diagnostic value of angiotensin I converting enzyme inhibition renography.

The effect of angiotensin converting enzyme (ACE) inhibition on the sensitivity of radionuclide renography in the diagnosis of a unilateral renal artery stenosis was tested both in a conscious dog model and in the human situation. ACE inhibition (10 mg enalaprilic acid, intravenously) markedly improved the sensitivity of [123I]hippuran renography in 10 renovascular hypertensive dogs with a mild to moderate unilateral renal artery stenosis from 50 to 100%. This improved sensitivity was due to an ACE-inhibition-induced delayed tracer handling at the stenotic side without an appreciable change in the renographic curve at the contralateral side. A similar phenomenon was observed in 15 hypertensive patients with an angiographically proved unilateral renal artery stenosis. Both [123I]hippuran and 99mTc-diethylenetriaminepentaacetic acid (DTPA) handling was delayed on the stenotic side after oral enalapril treatment. However, only a moderate increase in sensitivity was observed comparing control renograms to ACE-inhibition renograms: from 87 to 93% for hippuran, and from 60 to 86% for DTPA. Eight of these 15 patients underwent either surgery or angioplasty resulting in a successful correction of the stenosis. Hypertension was more or less cured in five patients. Each of these patients had shown an ACE-inhibition-induced change in the renogram at the stenotic side, suggesting that such a response may predict the curability of the hypertension. However, of the three patients that showed no blood pressure change upon successful revascularization, two showed a positive ACE-inhibition renogram. In conclusion, in an ideal setting as obtained in animal experiments, ACE inhibition improves the sensitivity of renographic studies to 100%. However, its value in the clinical setting needs more standardization.

Animals↗
PubMed1991

Effect of positive expiratory pressure breathing in patients with cystic fibrosis.

The effect of positive expiratory pressure breathing, alone and in combination with coughing, was investigated in eight patients with cystic fibrosis. Functional residual capacity and total lung capacity was measured with a body plethysmograph before, during, and immediately after breathing with expiratory pressure of 5 and 15 cm H2O, and after a coughing period. The positive expiratory pressure breathing was carried out five times for two minutes with a two minute interval between each period. Mucus transport was measured in a peripheral lung region and over the whole lung by a radioactive aerosol tracer technique. Clearance measurements were carried out continuously during positive expiratory pressure breathing and during a control period. Two minutes' breathing with an expiratory pressure of 5 and 15 cm H2O caused an increase in mean (SEM) functional residual capacity from 2.6 (0.1) to 3.6 (0.3) and 4.4 (0.5) 1 and an increase in total lung capacity from 5.1 (0.2) to 5.9 (0.3) and 6.9 (0.4) 1. Lung volumes were higher during breathing with an expiratory pressure of 15 cm H2O than with 5 cm H2O; both returned to baseline values immediately after positive expiratory pressure breathing. Spontaneous mucus clearance and mucus clearance by coughing were not influenced by positive expiratory pressure breathing at either expiratory pressure. Thus in patients with cystic fibrosis positive expiratory pressure breathing increases lung volumes in relation to the expiratory pressure imposed; these changes in lung volume did not, however, lead to an improvement of mucus transport.

Adolescent↗