The double puncture: an effective percutaneous technique for removing complex, multiple renal calculi

Percutaneous nephrostolithotomy, which can require a double puncture, is presently the method of choice in our institution for the removal of renal stones. Patients that underwent this procedure were evaluated to identify the possible reasons for the double puncture. Of 200 patients evaluated, 14 needed a second tract. The three variables that determined whether a second puncture was needed, in order of importance, were number and size of the stones, with second tracts needed in patients with multiple stones and staghorn calculi; anatomical variations of the renal collecting system itself, with bifid systems the most significant anatomic variation; and the dexterity of the radiologist in performing the puncture and the ability of the urologist to extract the stone. Second tracts were needed more frequently in patients who presented with stones in both the lower and middle poles of the collecting systems.     

Oral complications of cancer therapies. Pretherapy interventions to modify salivary dysfunction

Salivary gland dysfunction is a common side effect of cancer therapies. Salivary secretions are reduced rapidly after starting head and neck radiotherapy. Salivary gland dysfunction has also been linked to bone marrow transplantation and to cytotoxic chemotherapy. Salivary gland stimulation during radiation has been suggested as a means of reducing radiation damage. Results of an ongoing study investigating the effects of pilocarpine on radiation-induced salivary gland dysfunction suggest that parotid function was preserved, but not submandibular/sublingual function. Also, patients receiving pilocarpine had less frequent oral complaints. Further research is necessary to develop means of preventing or alleviating the salivary side effects of cancer therapies.     

Dose distribution following selective internal radiation therapy

Selective Internal Radiation Therapy is the intrahepatic arterial injection of microspheres labelled with 90Y. The microspheres lodge in the precapillary circulation of tumor resulting in internal radiation therapy. The activity of the 90Y injected is managed by successive administrations of labelled microspheres and after each injection probing the liver with a calibrated beta probe to assess the dose to the superficial layers of normal tissue. Predicted doses of 75 Gy have been delivered without subsequent evidence of radiation damage to normal cells. This contrasts with the complications resulting from doses in excess of 30 Gy delivered from external beam radiotherapy. Detailed analysis of microsphere distribution in a cubic centimeter of normal liver and the calculation of dose to a 3-dimensional fine grid has shown that the radiation distribution created by the finite size and distribution of the microspheres results in an highly heterogeneous dose pattern. It has been shown that a third of normal liver will receive less than 33.7% of the dose predicted by assuming an homogeneous distribution of 90Y.     

The preservation of red cell antigens at low ionic strength

Low-ionic-strength saline (LISS) techniques permit a safe and substantial reduction in incubation time and have therefore become the method of choice for antibody detection and compatibility testing in many transfusion laboratories. Consequently, the supply of reagent red cells (RBCs) in a low-ionic-strength preservative solution would remove the daily need for laboratories to wash and resuspend cells in LISS before use. However, the storage of fresh RBCs at low ionic strength in the presence of aminoglycoside antibiotics can cause a rapid loss of certain antigens, possibly as a result of the release of proteolytic enzymes from contaminating white cells. This article describes a low-ionic-strength solution that achieves preservation of antigens on liquid nitrogen-frozen-thawed RBCs for 21 days' storage at 4 degrees C.     

Visually perceived eye level and perceived elevation of objects: linearly additive influences from visual field pitch and from gravity

Observing a pitched visual field (i.e. tilted around a horizontal axis in the observer's frontal plane) results in large changes in the elevation visually perceived to correspond to eye level (VPEL) and in the perceived elevation and size of stationary objects viewed against the field. With topforward pitch (top toward observer) VPEL lies above true eye level and objects appear smaller and lower; with topbackward pitch VPEL lies below true eye level and objects appear larger and higher. Oscillation of the pitched field induces synchronous perceived oscillation of elevation of a stationary target viewed against the field. Typical VPEL settings deviated from true eye level by 20 degrees with the field pitched at 40 degrees, although some individuals mislocalized by as much as 40 degrees. VPEL varied linearly with visual field pitch with individual slopes for the relation between VPEL and visual field pitch ranging from +0.42 to +0.78 (avg = +0.56). The linear correlation (r) between VPEL in darkness and against an erect visual field was +0.91. The two relations--VPEL vs visual field pitch, VPEL in darkness vs VPEL in the erect illuminated visual field (slope approximately equal to 0.5)--are both accurately predicted by the linear model: VPEL = kvV + kbB; in which V is the influence of visual field structure and B is the influence of the body-referenced mechanism which combines information regarding the orientation of the head relative to gravity, the position of the eye in the orbit, and the vertical location of the image on the retina; kv and kb are the relative weights of V and B with kv + kb = 1. In an illuminated field kv = kb approximately equal to 0.5; in the dark kv = 0, kb = 1.     

The ferret as a model for endogenous synthesis and metabolism of N-nitrosamines

We have begun to evaluate the ferret as a model for studying gastric nitrosation and nitrosamine metabolism. Jugular cannulation allows convenient dosing and sampling of blood, and this technique has been used to study clearance of N-nitrosodimethylamine (NDMA) after intravenous, intraperitoneal and intragastric administration. NDMA metabolism can be inhibited by 4-methylpyrazole for up to 24 h; the accumulation of endogenously-synthesized NDMA can therefore be observed in animals following pretreatment with this compound. We have studied endogenous NDMA synthesis in animals dosed with dimethylamine and nitrite and in animals to which no NDMA precursors were administered.     

Focal physiological uncoupling of cerebral blood flow and oxidative metabolism during somatosensory stimulation in human subjects.

Coupling between cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) was studied using multiple sequential administrations of 15O-labeled radiotracers (half-life, 123 sec) and positron emission tomography. In the resting state an excellent correlation (mean r, 0.87) between CBF and CMRO2 was found when paired measurements of CBF and CMRO2 from multiple (30-48) brain regions were tested in each of 33 normal subjects. Regional uncoupling of CBF and CMRO2 was found, however, during neuronal activation induced by somatosensory stimulation. Stimulus-induced focal augmentation of cerebral blood flow (29% mean) far exceeded the concomitant local increase in tissue metabolic rate (mean, 5%), when resting-state and stimulated-state measurements were obtained in each of 9 subjects. Stimulus duration had no significant effect on response magnitude or on the degree of CBF-CMRO2 uncoupling observed. Dynamic, physiological regulation of CBF by a mechanism (neuronal or biochemical) dependent on neuronal firing per se, but independent of the cerebral metabolic rate of oxygen, is hypothesized.     

Stress and heart disease: evidence of associations between unemployment and heart disease from the OPCS Longitudinal Study

The OPCS Longitudinal Study has been used to study both overall and cause-specific mortality patterns in 1971-1981 among men and women directly or indirectly affected by unemployment in April 1971. Groups studied included men seeking work in 1971, the wives of men seeking work in 1971 and other women in the same households as a man seeking work in 1971. The findings of this project are summarized here and attention is focused on mortality from circulatory diseases, in particular ischaemic heart disease. The study provides evidence which could be seen as supporting hypotheses about relationships between stress and overall mortality, with a marked excess for suicides. The evidence with respect to ischaemic heart disease is positive but less convincing with excess mortality from this cause principally occurring among younger unemployed men and among the wives of men who were seeking work in 1971. Given the sharp contrasts in the pattern and levels of unemployment between 1971 and 1981 it is difficult to extrapolate from these findings to the present day.     

Anatomy of the accident scene: a prospective study of injury and mortality

This study of the accident scene focuses on the effects of vehicular deformity and restraint devices on occupant injury. In 500 patients evaluated in a Level I trauma center, seatbelts significantly reduced the likelihood of individuals' requiring the trauma center (P less than 0.0001). Seatbelts also significantly reduced the mortality rate of those who were transported to the trauma center (P less than 0.04). Dashboard intrusion correlated with pelvic (P less than 0.001) and femur (P less than 0.03) fractures, closed head injuries (P less than 0.001), and intraabdominal injuries (P less than 0.02). Steering wheel deformity correlated with pelvic fractures (P less than 0.001) and closed head injuries (P less than 0.005). Windshield violation correlated with closed head injuries (P less than 0.014) and spinal fractures (P less than 0.03). Irreparable vehicles correlated with pelvic (P less than 0.0001) and femur fractures (P less than 0.01), closed head injuries (P less than 0.0001) and intra-abdominal injuries (P less than 0.0001). The authors conclude that a careful examination of the accident scene for specific mechanisms of injury can lead to better prehospital care, more rapid and consistent diagnosis of injury, and improved patient outcome. Further prospective studies should accumulate data that will improve prehospital care, alert physicians to possible injury, increase community awareness of injury prevention, and improve vehicle construction.