Corticotropin response to combined administration of human corticotropin-releasing hormone and small-dose arginine vasopressin in normal subjects.

Arginine vasopressin (AVP) is known to potentiate corticotropin (ACTH) secretion by human corticotropin-releasing hormone (hCRH), and a combined administration of hCRH and AVP appears useful as a pituitary ACTH reserve test. This study was designed to evaluate the appropriate dose of AVP and its route of administration, for better estimation of pituitary ACTH reserve in humans, when used in combination with a conventional hCRH stimulation test. First, intravenous (IV) doses of hCRH (100 micrograms) and AVP (0, 0.1, and 0.3 U) were administered simultaneously in six normal subjects. Second, IV hCRH was administered with intramuscular (IM) AVP (0, 1.0, 3.0, and 5.0 U) in 10 normal subjects. Blood samples for measurement of plasma ACTH were obtained at 0, 15, 30, 45, 60, 90, and 120 minutes after the hCRH with and without AVP administration. The order of AVP doses was randomly chosen in each subject. The peak plasma ACTH level was 65.0 +/- 16.0 pg/mL (30 minutes) with hCRH alone and 139.5 +/- 35.6 pg/mL (15 minutes) with hCRH plus 0.3 U IV AVP in six normal subjects. Similarly, the peak plasma ACTH level was 43.5 +/- 5.6 pg/mL (30 minutes) with hCRH alone and 116.0 +/- 19.6 (15 minutes) and 96.6 +/- 24.0 pg/mL (15 minutes) with hCRH plus 3.0 and 5.0 U IM AVP in 10 normal subjects, respectively. The hCRH-induced ACTH responses (delta ACTH) with both IV and IM AVP were significantly (P less than .05) greater than the respective control values with hCRH alone. The responses (delta ACTH) were comparable between the two phases of 3.0 and 5.0 U IM AVP.(ABSTRACT TRUNCATED AT 250 WORDS)     

Atrial septal defect repair through limited lateral thoracotomy in children

Objective We have developed a surgical method for atrial septal defect repair through a limited right lateral thoracotomy in which the incision line begins 2 cm caudal from the lower angle of the scapula and ends at the midaxial line, thereby improving patient satisfaction with the cosmetic results of treatment. Methods We performed a retrospective review of 28 patients who underwent isolated atrial septal defect repair through a limited right lateral thoracotomy between January 2002 and August 2004. The mean age and mean body weight at the time of the operation were 85.8 months (range 9–236 months) and 23.0 kg (range 8.0–56.0 kg), respectively. All repaired defects were the ostium secundum type. Results There was no operative or late mortality and no late morbidity after a mean follow-up of 26 months (range 12–41 months). Echocardiography showed no residual shunt in any of the patients. The mean length of the skin incision was 7.8 cm (range 5.0–11.0 cm), and almost all the patients had satisfactory cosmetic results. Conclusion The atrial septal defect repair through a limited right lateral thoracotomy in pediatric patients showed satisfactory surgical results and excellent cosmetic results.     

Effect of tacrolimus and partial hepatectomy on transthyretin metabolism in rats

Liver transplantation, which serves as treatment of familial amyloidotic polyneuropathy (FAP), and domino liver transplantation, which utilizes resected livers from patients with FAP for treatment of liver diseases, may induce changes in transthyretin (TTR), a pathogenic FAP-related protein. To evaluate this possibility, we performed a 70% hepatectomy or administered tacrolimus to Dark Agouti (DA) rats for 7 days and then measured changes in liver TTR mRNA levels and changes in serum TTR concentrations. After hepatectomy, TTR mRNA levels decreased by 77%; at day 3, they returned to preoperative levels. Except for slightly elevated serum TTR concentrations 12 h after operation, serum TTR levels remained unchanged. Thus, partial hepatectomy did not influence serum TTR concentrations. After tacrolimus administration, TTR mRNA declined by 56% 12 h after the experiment started; however, after day 3, a rebound phenomenon occurred until day 7. Tacrolimus may facilitate serum TTR degradation, although production of TTR in the liver also increased. This finding -- that TTR, the source of FAP-inducing amyloid, did not increase after transplantation -- may help post-transplantation treatment of patients who have FAP and other liver diseases.     

Effects of intraaortic balloon position on renal artery blood flow.

Debate continues over what happens to renal blood flow when intraaortic balloons are adjacent to the renal arteries. Fourteen dogs were prepared by implanting instruments to measure heart rate; right atrial, pulmonary arterial, carotid arterial, and femoral arterial pressures; cardiac index; mixed venous oxygen saturation; urine output; and left and right renal blood flows. A 12-mL intraaortic balloon was inserted through the left (n = 9) or right (n = 5) femoral artery. The position of the balloon was randomized so that it was initially placed in either the control (thoracic) or renal position (at the level of the renal arteries). Intraaortic balloon pumping was performed for 4 hours in each position. In 8 dogs, at least one of the renal arteries had partial occlusion, 23% to 98% decrease in flow (mean decrease, 66%), while the intraaortic balloon was in the renal position. An intraaortic balloon in the renal position results in lower renal blood flow as well as a high risk (57%) of selective renal artery occlusion. Decreased renal blood flow is not apparent using conventional monitoring, as hemodynamics do not change.     

Effects of vanadyl sulfate on osteopenia in streptozotocin-induced diabetic (STZD) rats. Comparison with those of insulin]

The insulin mimetic effects of vanadium salts on glucose metabolism have been well-documented in STZD rats. In this study, the long-term effects of vanadyl sulfate (vanadium) on osteopenia in STZD rats were examined and compared with those of insulin. From 2 days after an intravenous injection of streptozotocin (30 mg/kg), the rats with hyperglycemia (> 300 mg/dl) received either vanadium (0, 0.02, 0.1 or 0.5 mg/ml) in drinking water or daily subcutaneous injections of insulin (0, 0.4 or 4.0 U/day) for 54 days. Their tibiae and femurs were examined by chemical analyses, by contact microradiography and by the method of double tetracycline labeling. Decreases in bone mass, bone density and in the rate of bone formation were observed in STZD rats. Development of these symptoms in the STZD rats with osteopenia was prevented by the administration of either vanadium or insulin in a dose-dependent fashion. The effects of vanadium at a dose of 0.5 mg/ml for preventing bone loss in STZD rats were similar to those of insulin at a dose of 4.0 U/day. These results indicate that vanadium has insulin mimetic effects on osteopenia in STZD rats.     

Left ventricular aneurysmectomy after myocardial infarction--comparative study between true aneurysms and functional aneurysms

Postinfarction left ventricular aneurysms are pathophysiologically divided into true, functional and false aneurysm. On 14 patients treated by aneurysmectomy, we studied the difference of pre- and post-operative cardiac function between true aneurysms (9 patients) and functional aneurysms (5 patients). The aneurysm area, which is expressed as the end-diastolic perimeter (akinetic or dyskinetic area/left ventricular silhouette), was 51.6 +/- 7.7% in the true aneurysms versus 35.7 +/- 6.0% in the functional aneurysms. Preoperatively, patients with a true aneurysm had a more severe clinical status than those with a functional aneurysm (Six of nine patients with a true aneurysm were in New York Heart Association functional class III or IV). Postoperatively, all patients except one with a true aneurysm and one with a functional aneurysm improved in clinical status. Nonaneurysmal EF, that is the function of the nonaneurysmal left ventricle, has a significant correlation to postoperative LVEF (r = 0.57, p less than 0.05). Nonaneurysmal EF was 54 +/- 4% in the true aneurysm group versus 51 +/- 16% in the functional aneurysm group. LVEF improved significantly (p less than 0.05) from 31 +/- 11% preoperatively to 55 +/- 10% postoperatively in the group of true aneurysm, but did not improved significantly from 43 +/- 12% to 50 +/- 9% in the functional aneurysm group. The postoperative akinetic area was 8.1 +/- 9.1% in the true aneurysm group versus 17.8 +/- 11.5% in the functional group. We conclude that larger and more adequate resection of aneurysms improves the cardiac function in the true aneurysm group more than in the functional aneurysm group.