Severe caffeine intoxication in a preterm neonate.
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Apnea↗
Biomedical subjects
H T Jongejan
Publications and source records attributed to H T Jongejan.
Potentiated nephrotoxicity of cisplatin when combined with amikacin comparing young and adult rats.
We compared the nephrotoxic interaction between cisplatin (CP) and amikacin (AM) in young and adult rats, using different dosage combinations. Following a single i.v. dose of CP, AM was administered s.c. for 14 days. The dose of CP was chosen to cause a 20%-50% fall in the glomerular filtration rate (GFR), while a dose of AM was chosen that had only a minimal effect on GFR. In adult rats, a decrease in GFR to 60% of the control value after CP alone was seriously aggravated by a non-toxic AM course given during 2 weeks after CP. In this combination, the GFR per 100 g body weight was reduced to 30% of control at week 2, which rose to 40% of control at week 15. In young rats, a non-toxic AM course did not aggravate the CP-induced impairment in GFR. However, when the dose of AM was increased to cause a 20% reduction in the GFR, the nephrotoxicity was potentiated. When measured at week 2, the GFR per 100 g body weight was 40% of control after the combined treatment compared with 80% of control after CP alone. As in adult rats, there was only a partial recovery of the GFR. In conclusion, in both adult and young rats, a course of AM following a single injection of CP potentiated CP-induced nephrotoxicity.
Aging↗
Potentiation of cis-diamminedichloroplatinum nephrotoxicity by amikacin in rats.
The nephrotoxic interaction between cis-diamminedichloroplatinum (CDDP) and amikacin (AMI) was studied in rats. Following a single dose of CDDP (5 mg/kg i.v.), AMI (60 mg/kg s.c.) was given for 14 days. When given alone CDDP caused a 40% fall in the glomerular filtration rate (GFR), whereas AMI alone had no effect on GFR. This nonnephrotoxic course of AMI potentiated the CDDP-induced fall in GFR. Only a limited recovery of renal function was observed during a 15-week follow-up period.
Amikacin↗
Radiation nephropathy in young and adult rats.
The effects of bilateral kidney irradiation were compared in young and adult rats. During a 1 year period after a single dose of 0, 7.5, 10, 12.5, or 15 Gy on both kidneys, renal function (glomerular filtration rate and effective renal plasma flow), urine composition, and systolic blood pressure were measured periodically. The first changes after irradiation were observed in the glomerular filtration rate and urine osmolality. One month after 10, 12.5, and 15 Gy, glomerular filtration rate (GFR) and urine osmolality had declined below control values in the young rats. After this initial decline, renal function increased at control rate or even more during the third and fourth month after irradiation but decreased progressively thereafter. In the adult rats, GFR and urine osmolality started to decrease 3 months after 10, 12.5, and 15 Gy. A rise in systolic blood pressure and proteinuria started 2-3 months after 12.5 and 15 Gy in both age groups. Early changes in the glomerular filtration rate with a drop in urine osmolality in young rats, occurring during a period of rapid renal development indicated an irradiation-induced inhibition of glomerular and tubular development. Although renal function deteriorated at a later time in adult rats, dose-response relationships obtained in young and adult rats did not show significant differences.
Aging↗
Interaction of cis-diamminedichloroplatinum and renal irradiation on renal function in the young and adult rat.
The interaction between single low doses of cis-diamminedichloroplatinum(II) (c-DDP) and renal irradiation (7.5, 10, 12.5 Gy) on renal function and systolic blood pressure (SBP) was investigated in young (3-4 weeks old, BW 45-65 g) and adult rats (over 12 weeks old, BW 230-290 g). The glomerular filtration rate (GFR) and effective renal plasma flow (ERPF), plasma creatinine, urea and SBP were measured over 24 weeks. Changes in ERPF, plasma creatinine and urea concentrations paralleled GFR changes, but tended to be less pronounced. In young rats, BW and GFR were 10-20% below control values after c-DDP administration (5 mg/kg BW). Irradiation caused a dose-dependent drop in GFR, starting 4 weeks after irradiation in young rats. When c-DDP was given immediately after irradiation to the young rats, the loss of renal function was more pronounced than after either treatment modality alone. Dose-effect curves for a greater than 25% reduction of the GFR relative to controls (ml/min) after 24 weeks gave an ED50 of 9.8 Gy for irradiation alone and 4.6 Gy for irradiation followed by c-DDP. After correction for the drug effect, dose-effect curves were similar for renal irradiation given alone or followed by c-DDP administration in young rats. In adult rats, c-DDP (2.5 mg/kg BW) or irradiation alone did not significantly alter renal function during the follow-up period. Only 12.5 Gy in combination with c-DDP, caused a significant reduction in GFR after 16 weeks in adult rats. In adult rats data were too limited for probit analysis.(ABSTRACT TRUNCATED AT 250 WORDS)
Age Factors↗
Hypertension after bilateral kidney irradiation in young and adult rats.
The mechanism of a rise in blood pressure after kidney irradiation is unclear but most likely of renal origin. We have investigated the role of the renin-angiotensin system and dietary salt restriction in the development of systolic hypertension after bilateral kidney irradiation in young and adult rats. Three to 12 months after a single X-ray dose of 7.5 or 12.5 Gy to both kidneys of young and adult rats, the systolic blood pressure (SBP) and plasma renin concentration (PRC) were measured regularly. A single X-ray dose of 12.5 Gy caused a moderate rise in SBP and a slight reduction in PRC in both young and adult rats. A dose of 7.5 Gy did not significantly alter the SBP or PRC during the follow-up period of 1 year. In a second experiment, the kidneys of young rats received an X-ray dose of 20 Gy. Subsequently, rats were kept on a standard diet (110 mmol sodium/kg) or a sodium-poor diet (10 mmol sodium/kg). On both diets, SBP started to rise rapidly 3 months after kidney irradiation. Sodium balance studies carried out at that time revealed an increased sodium retention in the irradiated rats compared to controls on the same diet. In rats on a low sodium intake, there was neither a delay nor an alleviation in the development of hypertension. Compared to controls, the PRC tended to be lower in irradiated rats up to 4 months after irradiation. Subsequently, malignant hypertension developed in all 20 Gy rats, resulting in pressure natriuresis, stimulating the renin-angiotensin system. Our findings indicated that hypertension after bilateral kidney irradiation was not primarily the result of an activation of the renin-angiotensin system. Although there were some indications that sodium retention played a role, dietary sodium restriction did not influence the development of hypertension.
Age Factors↗
Nephrotoxicity of cis-platin comparing young and adult rats.
The effect of Cis-platin on the glomerular filtration rate and effective renal plasma flow was determined using a radioisotope clearance technique in young (3 wk old) and adult (more than 12 wk old) rats. Cis-platin was administered intravenously in dosages ranging from 2.5 to 10 mg/kg body weight, either as a single dose or fractionated over 5 consecutive days. Following either dose regimen, identical total doses of Cis-platin caused less severe nephrotoxicity in young rats than in adult ones. In adult rats fractionated dosage significantly reduced nephrotoxicity. This was not observed in young rats. The difference in nephrotoxicity between young and adult rats was due to the renal handling of Cis-platin. After a single dose of 5 and 7.5 mg/kg body weight, platinum concentrations were measured in urine and renal tissue. During the first 2 days after Cis-platin administration, up to 60% of the amount of platinum injected was excreted in the urine of both age groups. There was a marked difference, however, in renal platinum concentration between the two groups. In young rats renal platinum concentration was only 63 and 49% of that in adult rats after 5 and 7.5 mg/kg body weight, respectively. We believe that this is due to the comparatively larger renal mass in relation to body weight in the young animals. Relatively more renal tissue provides at least partial protection against nephrotoxic drugs in these young rats.
Aging↗
Click-evoked oto-acoustic emissions in very-low-birth-weight infants: a cross-sectional data analysis.
For the purposes of studying the phenomenon of evoked oto-acoustic emissions (EOAEs) in very-low-birth-weight (VLBW) infants, and the conditions affecting the utility of EOAE ear screening in this population, click EOAEs were repeatedly recorded in ears of 144 VLBW infants, at different postconceptional ages of the infants and at two different test sites, i.e. in the neonatal high-care unit (ward), or at the neonatal outpatient clinic. The postconceptional age of the infants examined in the ward was 30-49 weeks and 37-66 weeks for the infants examined at the outpatient clinic. Overall 840 recording attempts were done. In the ward 86% of these attempts (388) were successful against 60% (of 452 attempts) at the outpatient clinic. In the latter group of infants the success rate of recording was only 33% at the corrected age of 6 months, which is significantly less than the 66% until the corrected age of 3 months. For a cross-sectional analysis of age effects one ear of each successfully recorded infant was selected. Analysis of the 127 successful recordings revealed that the EOAE prevalence was 71% in the ward (54% for infants receiving extra oxygen per naso) and 91% at the outpatient clinic. Compared with healthy newborns, VLBW infants are much more difficult to test, especially at the outpatient clinic. However, the EOAE prevalence at this test site is the highest and approaches that in healthy newborns. At the outpatient clinic response levels of EOAEs recorded approach levels found in healthy newborns. The higher success rate of recording in the ward and the lower EOAE prevalence are two counteracting factors as to the utility of EOAE-based ear screening of VLBW infants.
Cross-Sectional Studies↗