The effect of gender and age on growth hormone replacement in growth hormone-deficient patients.

We analyzed the effect of growth hormone replacement therapy (36 months) analyzed at a dose adjusted to maintain serum insulin-like growth factor-I level between the median and the upper end of the age-related reference range on bone mineral density, body composition, and carbohydrate metabolism with respect to gender and age in 20 adult patients (9 women, 11 men, mean age: 43 years, range: 21-61 years). The lumbar and femoral T-score was increased after 12 and after 18 months of therapy respectively in men (p < 0.001 and p = 0.002), but did not changed significantly in women. The increase of femoral T-score was greater in young men (< or = 45 years, n = 6) than old men (> 45 years, n = 5, p < 0.001). Body fat was lower in men than in women after 6 months (p = 0.002). The waist/hip ratio only decreased in women (p = 0.044). The waist circumference decreased in both genders after 6 months of therapy (p < 0.001), but more markedly in females than in males (p < 0.05). The sum of skinfold thicknesses was reduced in males after 6 months of therapy (p < 0.001). Changes in body composition parameters measured were independent of age. The glycosylated hemoglobin increased without sex or age difference after 12 months of initiation of therapy (p < 0.001), but fasting glucose and insulin levels did not change during the therapy. Our results indicate that the effect of growth hormone replacement on bone mineral content in adults is age- and gender-dependent, gender dependent on body composition, but independent of age and gender on carbohydrate metabolism.

Is it useful to measure supratentorial ICP in the presence of a posterior fossa lesion? Absence of transtentorial pressure gradients in an animal model.

Previous studies with animal models of supratentorial ICP elevation have demonstrated a pressure gradient between the supratentorial and the infratentorial compartments. The present study was designed to investigate the possible presence of such a gradient in the case of infratentorial ICP elevation. An inflatable infratentorial balloon catheter was implanted in seven domestic pigs. The infratentorial ICP (ICPi) was measured in the left cerebellar hemisphere, and the supratentorial ICP (ICPs) was measured in the left cerebral hemisphere. The corresponding pulse amplitudes (ICPi-PA, ICPs-PA) were recorded in both compartments, and the cerebral perfusion pressure (CPP) was calculated. ICPi and ICPs values prior to balloon inflation were 4.4 (SD 2.2) and 4.1 (SD 2.3) mm Hg, respectively, and increased to 63.1 (SD 32.6) and 62.3 (SD 28.1) mmHg after balloon inflation. ICPi-PA rose from 3.1 (SD 0.43) to 12.8 (SD 8.0) mmHg, and ICPs-PA rose from 3.2 (SD 0.63) to 13.0 (SD 7.1) mmHg. CPP decreased from 86.1 (SD 12.0) to 55.4 (SD 14.6) mm Hg. The paired difference between ICPi and ICPs values was 0.44 (SD 1.96) mmHg, and the paired difference of ICP amplitudes was 0.03 (SD 1.19) mmHg. All these differences in infratentorial and supratentorial values were statistically not significant. In conclusion, infratentorial ICP elevation in the presented pig model leads to a uniform ICP elevation in the intracranial space without development of a considerable pressure gradient below and above the tentorium. In the low pressure part of the ICP curve, cerebrospinal fluid connects the compartments and contributes to the pressure equilibrium. The early obstruction of the foramen magnum by intruding cerebellar tissue seems to isolate the infratentorial from the spinal compartment. In the high-pressure part of the curve, the upwards cerebellar transtentorial herniation takes over the pressure transfer, and the whole intracranial space can be considered as a single compartment in the pig.

Continuous monitoring of the partial pressure of oxygen in cerebral venous blood.

OBJECTIVE: Clinical oxygen monitoring in the injured brain is somewhat difficult. However, ischemia is one of the major factors responsible for secondary tissue damage after head injury or subarachnoid hemorrhage. Therefore, the aim of the present study was to investigate the value of continuously monitoring the partial pressure of oxygen in cerebral venous blood (PcvO2) during changes in intracranial pressure (ICP). METHODS: In eight domestic pigs with Clark type probes placed in the posterior third of the superior sagittal sinus, PcvO2 was continuously registered while ICP was stepwise elevated by an inflatable balloon placed below the tentorium. Arterial blood pressure was continuously monitored, cerebral perfusion pressure (CPP) was calculated, and arterial partial carbon dioxide pressure and partial pressure of oxygen were registered intermittently. RESULTS: The mean intraparenchymal ICP before the start of balloon inflation was 5 +/- 1 mm Hg, the mean CPP was 80 +/- 15 mm Hg, and the mean PcvO2 was 36 +/- 3 mm Hg. At maximum ICP elevation, CPP decreased to 20 +/- 12 mm Hg, PcvO2 decreased to 10 +/- 6 mm Hg, and ICP increased to 90 +/- 10 mm Hg. Strong linear correlations between ICP and PcvO2 and between CPP and PcvO2 were revealed, and mean correlation coefficients of 0.89 for ICP/PcvO2 and 0.73 for CPP/PcvO2 were calculated. CONCLUSION: The present study demonstrates that polarographic PcvO2 monitoring in the superior sagittal sinus is a reliable method for the early detection of reduced CPP during ICP elevation. This technique is capable of registering the global oxygen supply and oxygen consumption of the brain. It seems superior to jugular venous oxymetry and is better suited for clinical use because of a somewhat low artifact susceptibility.

Iatrogenic aortocaval fistula secondary to intervertebral disc surgery. A case report.

A case of iatrogenic aortocaval fistula is presented. The fistula arose in association with lumbar disc surgery. Its presence was immediately suspected and was promptly confirmed by aortography. Sudden deterioration of the patient's condition necessitated surgical correction of the fistula before the elected date. The successful corrective operation is described and some preventive recommendations are made.