A model for determination of total body protein synthesis based upon compartmental analysis of the plasma [15N] glycine decay curve

A model for whole body glycine nitrogen flux based on the compartmental analysis of plasma [¹⁵N] glycine decay curves is described and used for the measurements of (1) total body glycine nitrogen flux and the components of this flux in three healthy young adults and (2) total body protein synthesis based on the conversion of ¹⁵N to excretory products, ie, the sum of urinary [¹⁵N] urea and ¹⁵NH₃ and the amount of labeled urea remaining in the body at five hours following administration of [¹⁵N] glycine. The mean glycine nitrogen flux was 3.93 ± 0.42 mg N · kg^?1 · h^?1 (SEM). The major components of this flux are de novo synthesis of glycine, which accounts for 18% to 27%, and release from protein breakdown, which accounts for 62% to 73%. The outward pathways of glycine from the total body free glycine pool are conversion to other amino acids and oxidation to excretory end products (30% to 42%) and incorporation into protein, which accounts for 45% to 61% of glycine N loss from the metabolic pool. The mean rate of total body protein synthesis as determined by compartmental analysis was 3.56 g protein · kg^?1 · day^?1. The results that were obtained for protein synthesis and whole body glycine kinetics accord well with previous studies in normal adults, using the stochastic model.     

An appraisal of the efficacy and substantivity of the new high-potency sunscreens

Sarcoidosis in children less than 6 years of age is a rare occurrence. Affected patients, however, have a characteristic triad of involved organs—skin, joints, and eyes. Cutaneous changes usually take the form of asymptomatic eczematous or infiltrated plaques and papules. Swollen synovium produces articular changes which are much more visible than symptomatic—pain is minimal and range of motion is usually not substantially impaired. Involvement of the eye may produce much more severe and permanent damage, however. Chest and joint x-rays are usually normal.     

Social skills training and endogenous depression

The clinical response to social skills training was studied in four women with definite endogenous depression (melancholia) to ascertain if a behavioral intervention could be effective with more severe and pervasive affective syndromes. Three of four patients responded to social skills training, although both patients available for longitudinal follow-up relapsed within 24 months post-treatment. Implications for research and practice are discussed.     

Stress and cancer: The state of the art: Part 2

This paper reviews the evidence for specific personality and ego-defensive characteristics of cancer patients. The stress of loss and depression when combined with these personality factors seems to increase vulnerability to clinical cancer. A blind statistical sorting of cancer patients versus matched control patients on psychological items alone yielded results that bear promise for future psychological screening procedures. Three possible psychosomatic intervening processes are reviewed in order to provide suggestions for more specific research into the effects of personality and the stress of depression on vulnerability to cancer: relevant neurologic, endocrine, and immunologic data are reviewed in this perspective.     

The effect of phenytoin on the action potential of a vertebrate spinal neuron

The effect of phenytoin (PTN) 20 microgram/ml was tested on the passive membrane properties and the action potential of the dorsal cells in the spinal cord of the river lamprey. Dorsal cells are primary sensory neurons with no synaptic input, and thus allow examination of membrane properties in the absence of contaminating synaptic currents. PTN did not affect the resting membrane potential and slightly raised the input resistance. However, it greatly raised the threshold voltage and current for activation of action potentials by intracellularly injected current. It also reduced the maximum rate of rise of the action potential, the spike overshoot and the spike undershoot, while increasing the spike duration. In contrast to findings in other vertebrate sensory neurons, dorsal cell action potentials were blocked in zero sodium or tetrodotoxin, and not affected by zero calcium or 1 mM manganese. Thus they PTN on dorsal cells is that it partially blocks the activated sodium conductance increase of the action potential. Because a long delay was observed for maximal effect of PTN and for washout, it is postulated that the drug may require partitioning into the lipid membrane, or entry into the cell for its pharmacological action.     

Hydralazine in the long-term treatment of chronic heart failure: Lack of difference from placebo

Although hydralazine improves cardiac performance in patients with chronic left ventricular failure, its long-term clinical efficacy has not been established in controlled trials. We carried out a double-blind randomized trial of hydralazine (200 mg daily in 16 patients) versus placebo (16 patients) in patients with class III and IV symptoms while they were taking digitalis and diuretics. Maximal treadmill exercise time was determined prior to and at 4, 10, 18, and 26 weeks of hydralazine or placebo treatment; average follow-up was 20 weeks. We found no change in body weight, clinical class, resting heart rate and blood pressure, or heart size (by chest x-ray examination and echocardiogram) during treatment in either group. The total number of complicating clinical events was insignificantly fewer in the hydralazine treated group (8 vs 13). Control exercise duration in the hydralazine group averaged 259 ± 21 seconds (SEM), and increased to 347 ± 35 seconds at 4 weeks (p < 0.01) and 421 ± 38 seconds at 26 weeks (p < 0.001). Exercise duration also increased significantly in the placebo group, from 271 ± 30 seconds at control to 340 ± 44 seconds at 4 weeks (p < 0.02) and 339 ± 46 seconds at 26 weeks (p < 0.02). No differences between groups were significant. Left ventricular ejection fraction remained depressed and unchanged in both groups. Thus long-term vasodilator treatment with hydralazine alone is not significantly more effective than placebo in chronic heart failure.     

间皮细胞用作血管假体内腔铺被层可行性的研究

目的 了解间皮细胞抗凝与纤溶作用的强度 ,探讨其在防止腹膜粘连中的作用 ,并为血管假体内腔铺被细胞的选择提供依据。方法 取SD大鼠大网膜、主动脉、皮下结缔组织用作间皮、内皮及成纤维细胞的培养。取三类细胞第三代融合后48h的无血清培养液 ,放射免疫法测定6-酮 -PGF1α(前列环素的代谢产物)的含量 ,发色底物法测定组织型纤溶酶原激活物活性。结果 间皮细胞培养液中6-酮 -PGFlα浓度显著高于成纤维细胞及内皮细胞(P<0.01) ,纤溶酶原激活物活性也高于成纤维细胞(P<0.01) ,但与内皮细胞相比差别无显著性意义(P>0.05)。 结论 间皮细胞具有较强的抗凝作用与纤溶活性 ,在防止腹膜粘连中起重要作用 ,并可能成为血管假体内腔铺被层的理想材料。     

Aneurysmectomy and endocardial resection for ventricular tachycardia: Favorable hemodynamic and antiarrhythmic results in patients with global left ventricular dysfunction

Sixty-two patients underwent aneurysmectomy and endocardial resection for control of recurrent sustained ventricular tachycardia (VT). Forty patients also had coronary artery bypass grafting (CABG) (1.5 grafts per patient). The mean preoperative left ventricular end-diastolic pressure (LVEDP) was 18 ± 8 mm Hg, cardiac index (Cl) was 2.7 ± 0.7 L/min/m², and ejection fraction (EF) was 28 ± 10%. In a subset of 32 patients with clearly demarcated aneurysmal and contracting ventricular sections, the mean EF of the residual contracting section (CSEF) was 35 ± 13%, and 26 of these patients had a CSEF < 45%. There were five operative deaths (8%). No hemodynamic findings distinguished the patients who died during surgery. Patients with an LVEDP above the group mean or an overall EF below the group mean had an operative mortality of 10% and 7%, respectively. In the subgroup of 26 patients with a CSEF < 45%, the operative mortality was 12%. In the surgical survivors as a whole the LVEDP decreased from 17 ± 8 to 14 ± 5 mm Hg (p < 0.005) and the overall EF increased from 28 ± 9% to 39 ± 10% (p < 0.001) while the normal CI did not change. Linear regression analysis revealed that patients with the highest preoperative LVEDPs and the lowest overall EFs were most likely to have improvement in these parameters postoperatively. Patients with a preoperative CSEF < 45% had similar postoperative changes in their LVEDP (17 ± 6 to 15 ± 4 mm Hg) and overall EF (24 ± 7% to 38 ± 11%). In addition, the incidence of inducible VT postoperatively was similar in patients with a preoperative CSEF < 45% (4 of 23) and in the rest of the group (8 of 34, p = NS). We conclude that: (1) patients with ventricular aneurysms and medically refractory VT often have marked dysfunction of the residual contracting LV section; (2) aneurysmectomy and endocardial resection is an effective mode of therapy for VT and can be performed with a low operative mortality in this patient population; and (3) postoperatively the angiographic EF usually increases and the LVEDP often decreases, especially in patients with the most marked preoperative LV dysfunction.