Five hundred eighty-six consecutive frozen-section consultations performed during a I-year period were studied prospectively in order to assess the accuracy of the method and develop a quality control mechanism. The overall accuracy was 97.1%. The accuracy of the method with breast lesions was 97.9%. Specimens from the gastrointestinal tract and thyroid were incorrectly interpreted in 5% of the cases. The accuracy for lymph node specimens was 96.2%, with more than 50% consulted out of curiosity. The authors conclude that frozen section of lymph node is not recommended. Most of the errors were sampling errors made by the pathologist. The authors therefore conclude that in clinically suspected malignancy, more than one sample must be examined in order to decrease the false-negative diagnosis in frozen section.Cancer 57:377-379,1986.HE FROZEN-SECTION TECHNIQUE is now a well-es-T tablished procedure for rapid diagnosis of specimens.This procedure serves the surgeon by providing diagnosis, tissue recognition, and extent of resection, and thus helps in the making of therapeutic decisions. Because the diagnosis made by the pathologist from frozen section may have serious consequences for the treatment of the patient, a high degree of accuracy is mandatory and quality control is important. The surgeon constitutes a critical component of the diagnostic effort by his selection of the tissue from which the frozen section is done. No pathologist can overcome the handicap of being handed the wrong tissue. Consequently, both the surgeon and the pathologist must be advised of the other's problems and limitations if frozen-section conclusions are to give maximum service. The current study was undertaken in order to assess the accuracy of frozen section in a routine surgical pathologic service. Materials and MethodsA prospective survey was made of all surgical specimens diagnosed by frozen section at the Pathology Institute of Meir General Hospital in the course of 1 year. During this time, 7,073 specimens were received for surgical pathologic diagnosis, 586 of which were submitted for frozen-section diagnosis also. This group was a selected one in which preoperative histologic diagnosis of cancer was not made. Specimens in which preoperative diagnosis of cancer was made with biopsy specimens were excluded. Material for frozen section received from the surgical suites is examined immediately by the pathologist. The material is frozen with the use of a standard stainless steel heat sink built into the machine (American Optical Cryostate, Buffalo, NY) and is then sectioned and stained with hematoxylin and eosin. After a few minutes of preparation, the slides are transferred to the pathologist for microscopic examination. After consultation with another senior pathologist, the final diagnosis of the frozen section is established. The rest of the specimen is then fixed and stained by a routine histopathologic technique. The final pathologic diagnoses from the paraffin-block sections were recorded separately, and at the end of this s...

The effect of 2 urease inhibitors, hydroxyurea and thiourea, on experimental ascending pyelonephritis by P. mirabilis was studied in mice undergoing water diuresis. It was found that hydroxyurea significantly diminished the number of bacteria in the kidneys, the severity and number of lesions as well as the number of excreted bacteria. Thiourea, a weaker inhibitor, was less effective. The drugs prevented the establishment of infections but did not eliminate already existing ones. The mechanisms of hydroxyurea action were studied, as this drug also inhibits DNA synthesis. Hydroxyurea did not prevent infections by (urease-negative) E. coli, and selectively suppressed P. mirabilis in a mixed infection with E. coli.

Analysis of heart rate variability (HRV) is a promising diagnostic technique due to the noninvasive nature of the measurements involved and established correlations with disease severity, particularly in inflammation-linked disorders. However, the complexities underlying the interpretation of HRV complicate understanding the mechanisms that cause variability. Despite this, such interpretations are often found in literature. In this paper we explored mathematical modeling of the relationship between the autonomic nervous system and the heart, incorporating basic mechanisms such as perturbing mean values of oscillating autonomic activities and saturating signal transduction pathways to explore their impacts on HRV. We focused our analysis on human endotoxemia, a well-established, controlled experimental model of systemic inflammation that provokes changes in HRV representative of acute stress. By contrasting modeling results with published experimental data and analyses, we found that even a simple model linking the autonomic nervous system and the heart confound the interpretation of HRV changes in human endotoxemia. Multiple plausible alternative hypotheses, encoded in a model-based framework, equally reconciled experimental results. In total, our work illustrates how conventional assumptions about the relationships between autonomic activity and frequency-domain HRV metrics break down, even in a simple model. This underscores the need for further experimental work towards unraveling the underlying mechanisms of autonomic dysfunction and HRV changes in systemic inflammation. Understanding the extent of information encoded in HRV signals is critical in appropriately analyzing prior and future studies.

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A 17-year-old girl with refractory, but nonmalignant, hypertension and hypokalemia is presented. A state of primary hyperreninism and secondary hyperaldosteronism was found to exist, together with a renin-producing Sertoli cell ovarian tumor. Upon removal of the tumor, this patient attained both a normotensive and a normokalemic state. A brief review is given of renal and nonrenal renin-producing tumors.