Contrast MR of the brain after high-perfusion cardiopulmonary bypass.

PURPOSETo study the efficacy of contrast MR imaging in the evaluation of central nervous system complications in the cardiopulmonary bypass patient and attempt to explain their pathophysiology based on the MR appearance and the cardiopulmonary bypass protocol.METHODNineteen patients were prospectively studied with contrast MR examinations the day before and 3 to 7 days after cardiopulmonary bypass, to determine the nature, extent, and number of new postoperative MR abnormalities. Cardiopulmonary bypass parameters used in our institution included: membrane oxygenation, arterial filtration with a pore size of 25 microns, and a relatively high perfusion rate to produce a cardiac index of 2.0 to 2.5 L/min per m2.RESULTSThe preoperative noncontrast MR examination showed age-related changes and/or signs of ischemia in 60% of patients on the day before surgery. However, there was no abnormal enhancement or new T2 abnormalities on any postoperative MR examination to suggest hypoperfusion or emboli. None of the 19 patients developed overt neurologic deficits postoperatively. Review of the cardiopulmonary bypass protocol used indicated significant variations in technique at different institutions.CONCLUSIONContrast MR imaging demonstrated no new abnormalities in patients after cardiopulmonary bypass performed with strict in-line arterial filtration and relatively high perfusion. MR imaging is feasible in the early postoperative period after cardiopulmonary bypass and may offer a convenient method for evaluation of the neurologic impact of technical factors associated with cardiopulmonary bypass.     

Growth, metabolic and endocrine responses of broiler cockerels given a daily subcutaneous injection of natural or biosynthetic chicken growth hormone

The effects of daily injection of natural chicken growth hormone (ncGH) or recombinant-derived chicken growth hormone (rcGH) on growth, heat production rate, plasma hormone levels and body composition were determined in rapidly growing broiler chickens. Beginning at 3 wk of age, eight broiler chickens were given a daily injection of either bicarbonate buffer (control), 100 or 200 micrograms ncGH/kg body wt, or 200 micrograms rcGH/kg body wt for 14 d. Blood samples were taken preinjection and 4 h postinjection on d 7 and 14 of chicken growth hormone (GH) treatment. Compared to preinjection levels, plasma GH levels at 4 h postinjection were significantly (P less than 0.05) elevated by daily injection (per kg body wt) of 100 micrograms ncGH (2.3-fold), 200 micrograms ncGH (5.5-fold) or 200 micrograms rcGH (6.4-fold). Although exogenous chicken GH treatment failed to increase body weight gain, ncGH injections did increase (P less than 0.05) body fat content to 117% that of the control group. Daily injection of chicken GH did not alter plasma levels of immunoreactive insulin-like growth factor-I (IGF-I), thyroid hormones, insulin, glucagon or glucose. Feed efficiency, heat production rate and respiratory quotient were also not affected by chicken GH treatment. Plasma levels of nonesterified fatty acids were elevated (P less than 0.05) by treatment with 200 micrograms ncGH/kg body wt. In contrast to domestic mammals, it is apparent that exogenous chicken GH can not be used to increase lean body mass or improve productive efficiency in chickens. Our results indicate that exogenous chicken GH exerts a strong lipogenic, rather than lipolytic, action in rapidly growing broiler cockerels.     

PAF antagonism in vitro and in vivo by aglafoline from Aglaia elliptifolia Merr.

Aglafoline, isolated from Aglaia elliptifolia Merr, inhibited in a selective and concentration-dependent manner the aggregation and ATP release reaction induced in washed rabbit platelets by PAF (platelet-activating factor). The IC50 values of aglafoline, BN52021 and kadsurenone on PAF (3.6 nM)-induced platelet aggregation were about 50, 12 and 18 microM, respectively. Aglafoline also inhibited [3H]PAF (3.6 nM) binding to washed rabbit platelets with an IC50 value of 17.8 +/- 2.6 microM. The concentration-response curve of PAF-induced platelet aggregation was shifted to the right by aglafoline with pA2 and pA10 values of 5.97 and 5.04, respectively. Although thromboxane B2 formation caused by collagen and thrombin was partially suppressed by aglafoline, thromboxane B2 formation caused by ionophore A23187 and arachidonic acid was not affected. Aglafoline inhibited the [3H]inositol monophosphate formation caused by PAF but not that caused by collagen or thrombin in the presence of indomethacin (20 microM). The cAMP content of washed rabbit platelets was not affected by aglafoline. Rat femoral intravenous administration of aglafoline (10 mg/kg) did not affect blood pressure. However, aglafoline (10 mg/kg) both prophylactically and therapeutically antagonized PAF (2.5 micrograms/kg)-induced hypotensive shock in rats. Intravenous PAF (30 ng/kg) caused severe bronchoconstriction in guinea pigs. This effect was completely blocked by aglafoline. This implies aglafoline is an effective PAF antagonist not only in vitro, but also in vivo.     

Cerebral ischemia: evaluation with contrast-enhanced MR imaging

Eighty patients with a total of 82 ischemic lesions were examined with contrast-enhanced MR imaging 1 hr to 1 month after onset of symptoms. The studies were reviewed retrospectively to determine the presence of arterial enhancement and the patterns of parenchymal enhancement. Arterial enhancement was often detected on the initial MR examination (45%), was frequently demonstrated in cortical infarction (86%), in some cases preceded the development of signal changes on T2-weighted images, and resolved by 11 days. The presence of arterial enhancement appeared to be a better indicator of clinical severity than was the presence of proximal vessel occlusion on MR or angiographic studies. Two patterns of parenchymal enhancement were seen: progressive enhancement and early and/or intense enhancement. In patients with the progressive pattern, parenchymal enhancement on postcontrast T1-weighted images was rarely seen before 7 days, while signal abnormalities on T2-weighted images were intense during the first few days. The early and/or intense enhancement pattern was usually present within the first 3 days, approximated or exceeded the area and intensity of signal changes on T2-weighted images, and was usually associated with minimal or reversible neurologic sequelae (except when located in or near a watershed zone), suggesting a lesser degree of ischemic insult than was associated with the progressive pattern.(ABSTRACT TRUNCATED AT 250 WORDS)     

Hemangioma of the uterine cervix: sonographic and MR diagnosis

We present a case of cavernous hemangioma involving the cervix and lower uterine segment in a 30-year-old patient. Demonstration of findings on sonography and magnetic resonance characteristic for hemangioma led to cancellation of planned surgical resection for the clinically suspected uterine neoplasm.     

Spinal subarachnoid tumor seeding from intracranial metastasis: MR findings

We describe the magnetic resonance findings in two cases of spinal subarachnoid seeding from an intracranial metastatic lesion. Magnetic resonance imaging techniques using T1 and intermediate T1-T2 pulse sequences improve anatomical definition of the spinal cord-thecal sac and allow for optimal contrast to define metastatic deposits in the subarachnoid space. Heavily T2 weighted pulse sequences do not appear to be useful in the diagnosis of subarachnoid metastases.