Ethical dilemmas in today's nuclear medicine and radiology practice.

Throughout history, societies have developed their own codes of ethics, including those pertaining to the practice of medicine. In the United States, physicians have adopted a set of ethics based on religious values and historical teachings. We, as physicians, have been presented several codes of ethics, including the American Medical Association Code of Ethics and the American College of Radiology Code of Ethics. Over time, we have learned to appropriately apply these codes to our daily practice. With the advent of new technologies in imaging, we may lose sight as to the transfer of these principles to reflect current conditions. Recent history has shown a trend of new technology leading to potential misuse of this technology and further leading to stricter governmental regulations. It is the purpose of this review to give guidelines for dealing with new technologies, such as PET imaging, and we describe a radiologist's ethical responsibility in a doctor-patient relationship. A historical review of medical ethics will lead to discussions about various issues affecting radiologists and nuclear physicians. To be sure, not all ethical situations are black and white, and therefore there are many gray areas. The opinions expressed in this article are those of the authors and are based on extension of already established rules of ethical conduct.     

Loss of cables, a novel gene on chromosome 18q, in ovarian cancer.

Cables, a cyclin-dependent kinase (cdk) interacting protein, has recently been identified and mapped to human chromosome 18q11. Cables appears to be primarily involved in cell cycle regulation and cell proliferation. Overexpression of Cables in Hela and other cell lines inhibits cell proliferation and tumor formation. We hypothesize that loss of Cables expression is associated with ovarian cancer. To test our hypothesis, we examined Cables expression in the four most common subtypes of ovarian carcinomas: serous, endometrioid, mucinous, and clear cell. In addition, mucinous and serous borderline tumors were also included. Loss of Cables expression was observed at high frequency in ovarian serous (11 of 14 cases, 79%) and endometrioid (5 of 10 cases, 50%) carcinomas. In contrast, strong Cables staining was detected in all clear cell carcinomas (10 cases) and mucinous tumors (5 carcinomas and 5 borderline tumors). The majority of serous borderline tumors (11 of 14 cases, 79%) showed positive Cables staining, with the rest showing focal loss of Cables expression. Furthermore, RT-PCR revealed the lack of Cables mRNA in a human ovarian cancer xenograft. No correlation was noted between loss of Cables and histologic grade, tumor stage, and survival. In conclusion, our results indicate that loss of Cables is common in ovarian serous and endometrioid carcinomas and imply that Cables may be involved in the pathogenesis of these two types of ovarian carcinomas.     

Pinhole collimator scintigraphy in differential diagnosis of metastasis, fracture, and infections of the spine

The informational gains obtained by the use of pinhole collimator scintigraphy (PCS) have been well documented. The present study has been undertaken to prospectively investigate its efficacy in diagnosing several commonly occurring spinal diseases. Patient material consisted of metastatic cancer (39 vertebrae), compression fractures (33 vertebrae), tuberculous spondylitis (17 vertebrae), and pyogenic spondylitis (six vertebrae). PCS findings were characterized in terms of localization, appearance, and homogeneity of abnormal radionuclide accumulation. Thus, metastatic cancer manifested as diffusely or focally homogeneous accumulation within the vertebral body or as a typical short-segmental accumulation along the end-plate, whereas compression fracture manifested as characteristic board-like accumulation along the entire length of end-plates. Tuberculous spondylitis, on the other hand, revealed homogeneous accumulation throughout the vertebral body, and pyogenic spondylitis revealed accumulation at the end-zone of opposing vertebral bodies giving sandwich-like appearance. The disk space at the affected level was not narrowed in the former two diseases but it was narrowed in the latter two. It was concluded that PCS may be useful in differentiating metastatic cancer, compression fracture, tuberculous spondylitis, and pyogenic spondylitis.     

Impaired vagal heart rate control in coronary artery disease.

Heart rate variation in deep breathing, a sensitive non-invasive measure of cardiac parasympathetic activity, was measured in 63 patients with coronary artery disease, in 22 patients with atypical chest pain, and in 20 healthy symptom free volunteers. There was significantly less heart rate variation in deep breathing in the patients with coronary artery disease than in the healthy subjects. Twenty patients (32%) with coronary artery disease had lower than normal variation in heart rate. The patients with chest pain showed an intermediate heart rate response to deep breathing. Sinus arrhythmia in the patients with coronary artery disease was not related to the functional class, medication, number or location of narrowed vessels, or to the left ventricular ejection fraction, and end diastolic pressure. These results suggest that impairment of the parasympathetic nervous function is common in coronary artery disease.     

Urological manifestations of isolated iliac artery aneurysms

Three patients with iliac artery aneurysms were seen at our institution with the chief complaints owing to urological manifestations. Iliac artery aneurysms may present with a transrectally palpable mass, hematuria, bladder outlet obstruction, ureteral obstruction, retroperitoneal fibrosis or renal failure. Any such manifestations may bring the aneurysm to the attention of a urologist before diagnosis.     

Cobalt-dependent potentiation of net inward current density in Helix aspersa neurons.

A low concentration of transition metal ions Co2+ and Ni2+ increases the inward current density in neurons from the land snail Helix aspersa. The currents were measured using a single electrode voltage-clamp/internal perfusion method under conditions in which the external Na+ was replaced by Tris+, the predominant external current carrying cation was Ca2+, and the internal perfusate contained 120 mM Cs+/0 K+; 30 mM tetraethylammonium (TEA) was added externally to block K+ current. In the presence of Co2+ (3 mM) or Ni2+ (0.5 mM) inward Ca2+ currents were stimulated normally by voltage-dependent activation of Ca2+ channels. There was a 5-10% decrease in the rate of rise of the inward current. The principal effect of Co2+ and Ni2+ in increasing the current density seems to be a decrease in the rate at which the inward currents decline during a depolarizing voltage pulse. The results may be due to a decrease in a voltage-dependent or Ca(2+)-dependent outward current and/or an inhibition of Ca2+ channel inactivation. Outward current under these conditions (zero internal K+) was significant and most likely due to Cs+ efflux through the voltage-activated or Ca(2+)-activated nonspecific cation channels. Co2+ is an extremely effective blocker of this outward current. These results are not an artifact of internal perfusion or the special ionic conditions. Intracellular recording of unperfused neurons in normal Helix Ringer's solution showed that the Ca(2+)-dependent action potential duration was increased significantly by low concentrations of Co2+. This result is consistant with the Co(2+)-dependent increase in inward (depolarizing) current seen in voltage-clamp experiments.     

Paraffinoma in the urinary bladder: CT findings.

A case of a paraffinoma in the urinary bladder is presented. Plain radiography and intravenous urography showed a low attenuation filling defect in the urinary bladder, and CT demonstrated a lobulated fat-attenuation mass floating in the urinary bladder.     

手术对晚期卵巢癌患者机体免疫功能的影响

本文对12例晚期卵巢癌患者术前、术后的免疫功能分别进行了研究,以15例健康女性为对照。结果表明,卵巢癌患者的天然杀伤细胞活性及 T辅助细胞减低,T 抑制细胞增多,T 辅助细胞与 T 抑制细胞比值下降,与对照组相比,差别具有显著性。经瘤细胞减灭术后,机体免疫功能有不同程度的恢复,但总 T 淋巴细胞改变不明显。