Detection of local metabolic changes after progressive and stepwise reduction of renal blood flow in pigs

PURPOSE

Vascular complications after renal transplantation causing initially only partial renal ischemia can be difficult to discover in time to save the kidney. Our aims were to design an animal model allowing progressive and stepwise reduction of the arterial renal blood flow (RBF) and to investigate whether microdialysis could detect the subsequent metabolic changes.

MATERIALS AND METHODS

Eight pigs were used. Two microdialysis catheters were placed, one in the lateral renal cortex, the other just outside the renal capsule. Baseline measurements were obtained at steady state. Five injections of 100 mu-polyvinyl alcohol (PVA) particles were administered once every hour through an angiographic catheter placed in the renal artery to cause the RBF to gradually decline. The glomerular filtration rate (GFR) was estimated by (51)Cr-EDTA.

RESULTS

One diseased animal was excluded. GFR, RBF, and all metabolites measured by microdialysis remained stable during 2 hours of baseline measurements (ANOVA; P > .05). Within 30 minutes, the first injection of PVA particles caused a reduction of RBF to 40 +/- 13% of the baseline flow (t test; P < .001 vs baseline). Significant changes in cortical lactate and glutamate as well as extracapsular glutamate were also seen, at indicating ischemia (n = 7). Cortical glucose changed 60 minutes after baseline (n = 7).

CONCLUSION

Acute, stepwise renal blood flow reduction was achieved by injection of PVA particles. An early warning of developing ischemia is provided by microdialysis. This technique could be clinically valuable because it could be instrumental in improving survival of transplanted kidneys suffering from postoperative ischemia.

In vivo efficacy and pharmacokinetics of voriconazole in an animal model of dermatophytosis

The standard treatment for tinea capitis caused by Microsporum species for many years has been oral griseofulvin, which is no longer universally marketed. Voriconazole has been demonstrated to inhibit growth of Microsporum canis in vitro. We evaluated the efficacy and tissue pharmacokinetics of oral voriconazole in a guinea pig model of dermatophytosis. Guinea pigs (n = 16) were inoculated with M. canis conidia on razed skin. Voriconazole was dosed orally at 20 mg/kg/day for 12 days (days 3 to 14). The guinea pigs were scored clinically (redness and lesion severity) and mycologically (microscopy and culture) until day 17. Voriconazole concentrations were measured day 14 in blood, skin biopsy specimens, and interstitial fluid obtained by microdialysis in selected animals. Clinically, the voriconazole-treated animals had significantly less redness and lower lesion scores than untreated animals from days 7 and 10, respectively (P < 0.05). Skin scrapings from seven of eight animals in the voriconazole-treated group were microscopy and culture negative in contrast to zero of eight animals from the untreated group at day 14. The colony counts per specimen were significantly higher in samples from untreated animals (mean colony count of 28) than in the voriconazole-treated animals (<1 in the voriconazole group [P < 0.0001]). The voriconazole concentration in microdialysate (unbound) ranged from 0.9 to 2.0 microg/ml and in the skin biopsy specimens total from 9.1 to 35.9 microg/g. In conclusion, orally administered voriconazole leads to skin concentrations greater than the necessary MICs for Microsporum and was shown to be highly efficacious in an animal model of dermatophytosis. Voriconazole may be a future alternative for treatment of tinea capitis in humans.

Intestinal microdialysis--applicability, reproducibility and local tissue response in a pig model

BACKGROUND AND AIMS

Microdialysis has been applied to the intestinal wall for the purpose of monitoring local ischemia. The aim of this study was to investigate the applicability, reproducibility and local response to microdialysis in the intestinal wall.

MATERIALS AND METHODS

In 12 pigs two microdialysis probes were inserted into the ileal wall, one in the peritoneal cavity and one in the psoas muscle. Relative recovery was measured for all probes by the no net flux method. Metabolic measurements of glucose, lactate and glycerol were performed over six hours. The ileal wall segments containing the probes were processed for histological examination.

RESULTS

Large intra- and inter-group differences in the relative recovery were found between all locations. Absolute values of metabolites showed no significant changes during the study period. The lactate in blood was 25-30% of the intra-tissue values. A severe inflammatory reaction was seen in the ileal wall around all probes.

CONCLUSION

Measurement of the relative recovery is essential for valid measurements of metabolites when using microdialysis. The inflammatory reaction around the probe in the intestinal wall is likely to affect metabolism and measurements hereof. Therefore intestinal wall microdialysis seems confined to experimental research, and future studies should consider the intra-peritoneal approach.

[Hurricane-related orthopedic surgical admissions to an emergency department in December 1999]

INTRODUCTION

On 3 December, 1999, at 15.00 pm, hurricane Adam struck Esbjerg (Denmark). Wind velocity exceeded 33 m/s, the strongest hurricane ever recorded in Denmark during the last century. This article describes and analyses the orthopaedic impact of the hurricane on a local hospital in Esbjerg.

MATERIALS AND METHODS

We examined retrospectively all the patients treated at the Emergency Department from 3 pm on 3 December and for the following 24 hours. For comparison, we used the records of all patients treated at the Emergency Department in the same time interval on the first three Fridays in December from 1994 to 1998.

RESULTS

No hurricane-associated deaths were recorded, but the number of patients treated on 3 December was significantly higher than that recorded in the period 1994-1998 (159 versus 74, p < 0.001). The main diagnosis was similar to that of the previous years, but more people sought treatment at the Emergency Department. Sixty-eight percent of the recorded injuries were injuries to the upper and lower extremities and 22% to the head and neck.

DISCUSSION

Hurricanes can lead to substantial morbidity and mortality. Early warning is the most effective way of reducing death and injury. People should seek cover and follow the instructions given by the news media. Educational programmes for the medical staff of the Emergency Department should be made available.

[Baker's cysts in children. A retrospective study at the hospitals in the county of Rebe from 1992 to 1998]

Popliteal cysts or Baker's cysts in childhood is a rare disease usually found by the parents. The purpose of this study is to study the recurrence rate after primary surgical resection and conservative treatment of the cysts. We retrospectively found 20 children with Baker's cysts treated at Ribe Amts Hospitals during the period 1992-1998. Thirteen patients were treated conservatively and seven had a surgical resection of the cysts performed. Of the 13 conservatively treated patients the cysts was still present in six patients (46%). In seven patients the cysts had disappeared within nine months. In the surgically treated group the cysts recurred in three patients (43%). Surgical intervention for Baker's cysts in children should only be performed after thorough consideration, due to a high recurrence rate.