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Biomedical subjects

E Peperkamp

Publications and source records attributed to E Peperkamp.

12 recordsLinked to original sources

Endophthalmitis: incidence, therapy and visual outcome in the period 1983-1992 in the Rotterdam Eye Hospital.

From 1983 to 1992, 134 patients were treated for clinically suspected endophthalmitis. 61% of this endophthalmitis population consisted of cases that were referred to our clinic. In this nine year period antibiotic treatment was carried out according to three consecutively used guidelines. These three treatment schemes differed in antibiotic spectrum and mode of antibiotic delivery. In 68 patients we performed vitrectomy on account of clinical deterioration under antibiotic treatment. We did not find significant differences in visual outcome between the three treatment groups. The incidence of endophthalmitis following cataract or vitreous surgery did not change throughout the study period. There was however a dramatic decrease in incidence of post-traumatic endophthalmitis following the introduction of a prophylactic antibiotic treatment scheme consisting of fortified gentamicin and cefazolin eyedrops, and intravenously and subconjunctivally administered gentamicin, cefazolin, and clindamycin. In 55 of 68 cases in which vitrectomy was performed in conjunction with intravitreal antibiotics, a vitreous or anterior chamber specimen was cultured. 36 patients had a positive culture result. In the group with positive culture result 42% had better visual acuity in the post-treatment period than before treatment. In the group with a sterile culture result 79% had better vision after treatment.

Anti-Bacterial Agents

Plasma prorenin as an early marker of microvascular disease in patients with diabetes mellitus.

To test the hypothesis that a high plasma prorenin can be used as an early marker of microvascular complications in patients with diabetes mellitus plasma prorenin was measured in 44 patients with urinary albumin excretion between 30 and 300 mg/24 h (microalbuminuria) and 120 patients with urinary albumin excretion below 30 mg/24 h (normoalbuminuria). A high plasma prorenin was associated with diabetic retinopathy, particularly the proliferative type, serum creatinine and the 24 h urinary albumin excretion rate. Plasma prorenin was not correlated with age, duration of diabetes, glycosylated hemoglobin, blood glucose, and blood pressure. The association between elevated plasma prorenin and retinopathy remained significant after adjustment for serum creatinine and albumin excretion. Independent of the presence or absence of microalbuminuria, the mean plasma level of prorenin was not above normal in patients without retinopathy and was 2 to 3 times normal in patients with proliferative retinopathy. Thus retinopathy appears to be an important determinant of abnormally high plasma prorenin. Angiotensin converting enzyme (ACE) was elevated in the patients with diabetes mellitus as compared to control subjects but the plasma levels of ACE in diabetics with normoalbuminuria was not significantly different from the group with microalbuminuria. Plasma prorenin was not associated with ACE. A plasma level of prorenin of 225 mU/L had a sensitivity of 0.84 and a specificity of 0.82 for detecting the presence of microalbuminuria.

Adult

Analysis of local antibody production in the vitreous humor of patients with severe uveitis.

We analyzed the local antibody production in vitreous humor samples collected during vitrectomy in patients with severe vision-threatening uveitis. In 24 patients, paired serum and undiluted vitreous humor samples were collected and tested for antibodies against Toxoplasma gondii, herpes simplex virus, varicella-zoster virus, cytomegalovirus, Epstein-Barr virus, and Toxocara canis. Total IgG and the Goldmann-Witmer coefficient were determined. The initial diagnosis of ocular toxoplasmosis could be confirmed in six of the seven patients. The seventh patient showed a local antibody production against herpes simplex virus. One of the three patients with chronic panuveitis at initial diagnosis showed a local antibody production against T. gondii. These last two findings resulted in a change in medical treatment. Analysis of local antibody production in vitreous humor samples is a valuable diagnostic tool.

Animals

Retinal folds through the macula.

In a series of 137 consecutive conventional primary retinal detachment repairs we postoperatively found retinal folds through the macula in four cases (2.8%). All four patients had presented with an acute, bullous, superior detachment, and had been treated with an encircling band, drainage of subretinal fluid, injection of an air/gas mixture, cryocoagulation, and a radial buckle to close the largest retinal tear. Redundant retina (created by the encircling band and possibly by stretching in the bullous detachment) became folded either by compression by the gas-bubble in the recumbent patient, or by a steam roller action of the bubble when the patient sat up. In acute bullous detachments, we try to avoid this complication by using an air/gas bubble which is not greater than necessary to tampon the retinal break, and by positioning the patient in such a way that residual subretinal fluid is pressed away from the posterior pole.

Follow-Up Studies

High plasma prorenin in diabetes mellitus and its correlation with some complications.

Plasma prorenin is abnormally high, whereas renin is normal or even low, in many patients with long-standing diabetes mellitus complicated by microvascular disease. Nephropathy or autonomic neuropathy has been put forward as a cause. We found that in 223 consecutive diabetics prorenin correlated positively with serum creatinine, the presence of macroalbuminuria (greater than 250 mg/L), and the presence of diabetic retinopathy, particularly the proliferative type. This correlation did not depend on the presence of neuropathy or whether the patient was receiving insulin. It was also independent of sex, age, duration of diabetes, blood pressure, and blood levels of glucose and hemoglobin-A1c. The association between elevated prorenin and retinopathy remained significant after adjustment for creatinine and the presence of macroalbuminuria. Of the whole group of diabetics 94 consecutive patients were assessed for the presence of microalbuminuria (30-300 mg/24 h). Independently of the presence of micro- or macroalbuminuria, the mean level of prorenin was not above normal in the patients without retinopathy and was 2-3 times normal in those with proliferative retinopathy. Thus, retinopathy appears to be a more important determinant of abnormally high prorenin than nephropathy. In addition, the renal vein to artery ratio of prorenin in 7 diabetics with both advanced nephropathy and proliferative retinopathy was not elevated, despite the high peripheral venous prorenin level and the impaired renal perfusion. Thus, the abnormally high prorenin level in these patients could not be explained by abnormal secretion by the kidneys. Finally, prorenin was not high in 16 nondiabetics with loss of sympathetic activity due to chronic autonomic neuropathy, which indicates that in the absence of diabetes, this type of autonomic failure is not sufficient to cause the high prorenin levels seen in diabetics. Our findings are evidence that abnormally high plasma prorenin levels in diabetics are not an immediate consequence of altered glucose metabolism. This abnormality is related to the development of microvascular disease in the eye and kidney and is at least in part due to decreased clearance of prorenin from the circulation, increased production from extrarenal sources, or both.

Albuminuria

Renin, prorenin, and immunoreactive renin in vitreous fluid from eyes with and without diabetic retinopathy.

Renin, prorenin, and immunoreactive renin were present in vitreous and subretinal fluid of eyes from subjects with and without diabetic retinopathy. Renin substrate, albumin, transferrin, and immunoglobin G were also found in these ocular fluids. In many samples renin levels were close to the detection limit of the assay. The levels of renin substrate, albumin, transferrin, and immunoglobulin G varied widely among ocular fluid samples, but in each individual sample the levels were, relative to each other, similar to those in plasma. In contrast, the prorenin level in ocular fluid was up to 100 times higher than expected on the basis of the plasma protein content of ocular fluid. Moreover, there was little difference in prorenin concentrations between samples with low and high plasma protein contents. Prorenin, relative to albumin and other plasma proteins, was higher in vitreous fluid from eyes with proliferative diabetic retinopathy complicated by traction retinal detachment than in eyes of nondiabetic subjects with spontaneous retinal detachment. It appears that prorenin (and possibly renin) in ocular fluid is controlled by an active and specific process, possibly local synthesis within the eye. In view of the vascular actions of angiotensin II, an intraocular renin-angiotensin system may play a role in diabetic retinopathy.

Adult

Basal iridectomy at 6 o'clock in the aphakic eye treated with silicone oil: prevention of keratopathy and secondary glaucoma.

In the aphakic eye, with intact iris diaphragm, silicone oil has frequently caused a pupillary block. In this situation aqueous humour accumulates behind the iris and forces silicone oil through the pupil into the anterior chamber. An iridectomy at the 6 o'clock position can effectively prevent this pupillary block. The iridectomy allows free passage of aqueous to the anterior chamber which remains free of silicone oil. No permanent contact with silicone oil and the cornea is established, and development of keratopathy is prevented. The effect of this iridectomy in 62 eyes with intact iris diaphragm in patients in Rotterdam (35 cases) and Nagoya (27 cases) is demonstrated. Only in 6.5% of the cases was silicone oil present in the anterior chamber at the end of the follow-up period of 7 months.

Aphakia, Postcataract

Immune electron microscopy and a cultural test in the diagnosis of adenovirus ocular infection.

Immune electron microscopy (IEM) and virus isolation in cell culture were compared in the diagnosis of adenovirus ocular infection during an outbreak of the disease in 1979. Eleven of 14 patients with a keratoconjunctivitis clinically indicative of adenovirus infection had IEM evidence of adenovirus infection or had the virus isolated from ocular swabs. The IEM was positive in 8 patients. Virus as isolated from 10 patients. IEM was positive in one culture negative patient. Since IEM provides a rapid and sensitive method for the detection of adenovirus in human tears, it may be a valuable diagnostic tool for the clinician.

Adenoviridae Infections

Experiences with laser trabeculopuncture.

54 eyes with glaucoma simplex and 21 eyes with secondary chronic glaucoma were treated once by laser trabeculopuncture and followed up for at least 1 year. The results in the first group were encouraging, in the second group disappointing. L.T.P. appears to be a technique with which, in the majority of cases of glaucoma simplex, a sustained moderate decrease in pressure can be obtained.

Follow-Up Studies

Incidence of cataracts in rhesus monkeys treated with whole-body irradiation.

The incidence of cataract formation was investigated in rhesus monkeys exposed to different doses of whole-body irradiation. Application of 850-900 rad (8.5-9 Gy) caused cataracts in 17% of the monkeys within 3 years after treatment; after 10 to 15 years, incidence increased to 100%. "Young" lenses showed a significantly lower incidence than "adult" lenses, although no differences in the stage of cataractogenesis could be demonstrated. Sex differences did not play a role in incidence and severity of cataracts. Lower doses (400 rad or 4 Gy) did not cause cataracts. In view of the close similarity between monkeys and humans, these results indicate that a single dose of 850-900 rad, sometimes employed in the treatment of acute myeloid leukemia in children, carries a strong risk of cataract development.

Animals