Pathophysiology of obstructive nephropathy

Summary Obstruction of the urinary tract is a common and often reversible cause of renal failure. Partial chronic obstruction of the urinary tract may lead to progressive atrophy and destruction of nephrons resulting in chronic renal failure; in contrast complete obstruction occurring suddenly may result in the development of acute renal failure. The mechanisms by which obstructive diseases affect renal function are incompletely understood. Much information has been obtained using animals models of obstruction, ranging from studies using whole animal to those using single nephrons. In this review, the effect of either unilateral or bilateral obstruction on renal blood flow, glomerular filtration rate and tubular function is presented. The possible involvement of angiotensin II, thromboxan A₂, macrophage-derived products and platelet-activating factor in the pathophysiology of obstruction is discussed.This work was supported by the Frank Strick Foundation and the Joseph Alexander Foundation.     

The NMDA antagonists, CPP and CGS 19755, lack affinity for central benzodiazepine receptors

CPP (3-(2-carboxypiperazin-4-yl-propyl-1-phosphonic acid), a rigid analog of AP7 (2-amino-7-phosphonoheptanoate), previously shown to be a selective antagonist of the NMDA (N-methyl-D-aspartate) receptor (IC50 = 209 nM) has been reported to be exceptionally active (IC50 = 430 pM) at benzodiazepine binding sites. Re-examination of CPP, and the rigid AP5 analog, CGS 19755 (cis-4-phosphonomethyl-2-piperidine carboxylic acid; 0.001-10,000 nM), showed that, as previously reported, neither compound affected the binding of [3H]flunitrazepam. These compounds are thus selective NMDA receptor antagonists.     

Influence of naproxen therapy on natural killer cytotoxicity and antibody-dependent cellular cytotoxicity against cells infected with herpes simplex virus

Natural killer cytotoxicity (NKC) and antibody-dependent cellular cytotoxicity (ADCC) represent one of the body's primary lines of defense against viral infections, including herpes simplex (HSV). This immune defense system is negatively influenced by prostaglandins. A project was undertaken to evaluate the influence of an antiprostaglandin agent in vivo on these cytotoxic effects against cells infected with HSV. Thirteen subjects without previous histories of clinical herpes simplex infection were studied during menses with and without naproxen therapy. A statistically significant augmentation (p = 0.05) of natural killer-cell function was identified in mononuclear cells during therapy. Subjects with baseline cytotoxicity of less than 45% demonstrated consistent elevations during naproxen therapy. No other significant differences could be found for mononuclear or polymorphonuclear cells with regard to NKC and ADCC. There appears to be a subset of patients who may benefit from immunologic augmentation with antiprostaglandin agents when experiencing herpes simplex virus infection.     

Cribriform variant of papillary thyroid carcinoma

We report a case of papillary carcinoma of the thyroid exhibiting unusual cribriform structures. The thyroid origin of the tumor was confirmed by positive immunostaining for thyroglobulin.     

Breast preserving therapy: shorter treatment duration by the peroperative introduction of iridium guide needles]

In the Deventer Radiotherapeutic Institute from January 1981 through December 1989, 359 patients who had undergone a breast-saving operation were irradiated. Since 1987, iridium guiding needles were introduced peroperatively in 79 of these patients. Subsequently, irradiation was administered. With this method the total duration of treatment was 16 days shorter on average than in patients who postoperatively were treated with iridium or external irradiation; also, the patients treated peroperatively needed only to be anaesthetized once. In addition, better positioning of the needles was possible, reducing the risk of faulty localization. The follow-up was short but the preliminary results of the treatment were good (one local recurrence after an average follow-up of 20 months) and no adverse effect on wound healing was seen.     

Proprioceptive contributions to tactile identification of figures: dependence on figure size

Studies on the recognition of objects or shapes explored by a hand or finger have concentrated on the relative merits of different methods of exploration--in particular, whether the exploring hand or finger is moved by the subject himself (active), is guided by an assistant (passive), or remains stationary with the shape being moved by an assistant (tactile). These factors, together with another variable--the size of the explored shape--were investigated in twelve normal adults whose task, without the aid of vision, was to explore and identify various shapes with the tip of the extended right index finger. Two series of shapes were used, a large (15 cm) and small (3 cm) series, both of which consisted of twelve shapes each being a variant of the letter 'S'. The shapes were outlined as rows of Braille-like dots on a flat surface. Exploration was also tested in the proprioceptive mode, in which the exploring hand was guided by an assistant around a shape which was simply drawn on the surface so as to give a minimum of tactile information. For neither large nor small shapes could we demonstrate differences between active, passive and proprioceptive exploration. For the small shapes, the active, passive and proprioceptive modes gave no advantage over purely tactile assessment. However, for the larger shapes, active, passive and proprioceptive modes allowed better identification than movement of the shape. Thus, purely cutaneous signals appear sufficient for optimal discrimination of small figures but proprioceptive signals, generated by movement, are needed for optimal discrimination of larger figures.