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Biomedical subjects

I Schafer

Publications and source records attributed to I Schafer.

10 recordsLinked to original sources
PubMed2001

Sensitivity and positive predictive values of presurgical clinical diagnosis of excised benign and malignant skin tumors: a prospective study of 835 lesions in 778 patients.

This article reports on the sensitivity and positive predictive value of clinical diagnosis of benign and malignant skin tumors by expert plastic surgeons in an Israeli clinic. Most published reports have focused on the sensitivity of clinicians' diagnoses, a general measure of the physician's skill that does not predict the rate of accuracy of a physician's diagnoses. Our study of 835 lesions in 778 patients, one of the largest Israeli series, assesses the clinical diagnosis of malignant and benign skin tumors and is one of the few that provide information on the positive predictive value, the measure that is of interest to both physicians and patients. The majority of tumors were benign (56.8 percent), 31.6 percent were malignant, and 11.6 percent were premalignant. Among the 474 benign lesions, 46 percent were nevi. The most common nevi subclass was compound nevi (53 percent), 9 percent of the nevi were dysplastic, and 5 percent were blue nevi. The most common malignant tumor was basal cell carcinoma, accounting for 78 percent of malignant tumors. Although sensitivity for clinical diagnosis of malignancy was 91.3 percent, the positive predictive value for clinical diagnosis of malignancy was 71.3 percent. The sensitivity rate for clinically diagnosing premalignant tumors was 42.3 percent, whereas the positive predictive value for these diagnoses was higher (64.1 percent). The sensitivity rate for diagnosis of all benign lesions was 85.9 percent, and the positive predictive value was 94.2 percent. The sensitivity rate for diagnosis of all nevi was 87.6 percent, and the positive predictive value was 85.7 percent: i.e., only seven of the 218 pathologically proven diagnoses of nevi (3.2 percent) were falsely diagnosed as malignant lesions. Even more interestingly, five of the 223 clinical diagnoses of nevi (2.2 percent) were pathologically proven to be malignant melanomas, and seven were found to be premalignant lesions (3.1 percent). It was concluded that publications which report only on the sensitivity neglect to provide information of interest regarding the positive predictive value. Often, positive predictive value is qualitatively different from the sensitivity, and thus relying only on the sensitivity may lead to incorrect evaluation of a clinical judgment, which may result in erroneous surgical decisions.

Adolescent↗
PubMed2000

On low-level tritium measurements with LSC Quantulus

Low-level measurements of 3H have been made with the "Quantulus" liquid scintillation counter (LSC) using different scintillation cocktails together with selected types of counting vials. Comparisons were made between counters at the underground laboratory "Felsenkeller" (110 m water equivalent) and in an above ground laboratory (0 m water equivalent) of the TU Freiberg. In the underground laboratory, the background is strongly influenced by the beta-decay of the 220Rn-daughter 212Pb (T(1/2) = 10.6 h) from the laboratory air, stimulating luminescence irradiation in the vial. The effective background count rate in the 3H-window (having subtracted the "luminescence effect") in the underground laboratory is two times lower than that in the above ground laboratory due to the better shielding of cosmic rays.

Journal Article↗
PubMed2000

Disseminated granuloma annulare following erythema multiforme minor.

A 44-year-old woman presented with erythema multiforme minor followed by disseminated granuloma annulare 4 weeks later. The patient was not taking any medication and had no history of herpes simplex infection. Involvement of a delayed-type hypersensitivity reaction in the pathogenesis of these two well known disorders, as suggested by immunological investigations, may explain their concurrence in our patient. The substitution of the erythema multiforme minor lesions by an eruption of disseminated granuloma annulare at the same sites suggests the possibility of a Koebner phenomenon or an isotopic response.

Adult↗
PubMed1999

Effects of bupivacaine on human erythrocytes submitted to stress and evidence for an interaction between bupivacaine and flumazenil.

AIMS: To examine the effects of bupivacaine on erythrocytes submitted to an oxidative stress (AAPH) and to provide evidence for an in vitro interaction between bupivacaine and flumazenil. METHODS: Human erythrocytes were studied with or without AAPH in the presence of different concentrations of bupivacaine (0.15, 0.3, 0.9 and 1.8 mmol l-1 ), or flumazenil (0.16 mmol l-1 ) and with the association of flumazenil and two doses of bupivacaine (0.15 and 0.3 mmol l-1 ). Potassium efflux was measured by flame photometry at T0, and every 30 min for 2 h. RESULTS: In the absence of AAPH, extracellular potassium remained unchanged. Oxidative stress induced a significant increase in extracellular potassium, which was not modified by incubation with flumazenil. Bupivacaine significantly lowered the increase in extracellular potassium in a dose-related fashion. The association with flumazenil blunted the effects of bupivacaine. Discussion In this model, bupivacaine proved effective in protecting erythrocytes against oxidative stress. Flumazenil interacted with bupivacaine and blunted its protective effects.

Anesthetics, Local↗
PubMed1996

Measurement of the maturation parameter by using computer-assisted interactive image analysis may be helpful in the differential diagnosis between compound Spitz nevus and malignant melanoma.

The so-called maturation parameter (MP) (that is, the ratio of the mean nuclear areas in the deep portion and in the superficial portion of a tumor) was measured and calculated using a computer-assisted interactive image analysis system in 29 compound Spitz nevi (SNs) and 37 primary invasive cutaneous malignant melanomas (MMs), of which 16 and 14 lesions, respectively, measured up to 1 mm in Breslow thickness (that is, thin). The MPs of the SNs and MMs were found to be 0.37-0.89 (mean +/- SD, 0.64 +/- 0.1) and 0.81-1.16 (mean +/- SD, 0.96 +/- 0.1), respectively (p < 0.001). The MPs of the subgroups of thin SNs and MMs were 0.56-0.87 (mean +/- SD, 0.67 +/- 0.1) and 0.86-1.10 (mean +/- SD, 0.98 +/- 0.1), respectively (p < 0.001). Most of the SNs and MMs had MP values of < 0.81 and > 0.89, respectively. This pattern of distribution prevailed in the subgroup of thin lesions. Thus, the previously shown difference in MPs between SN and MM for thicker lesions (> or = 1.0 mm) was demonstrated in this study in thin lesions (< or = 1.0 mm) as well. Although a relatively small area of overlap in MP values exists between compound SNs and MMs, including the thin ones, below this area the lower the MP value the more likely the diagnosis is SN, and vice versa.

Cell Nucleus↗
PubMed1994

Hydronephrosis due to fibroepithelial ureteral polyp in a child.

The case of a 5-year-old girl, complaining of left abdominal and flank pain, is reported. The excretory urogram and retrograde pyelography showed an obstruction located at the left upper ureter with hydronephrosis. Exploration revealed a small ureteral polyp obstructing the lumen. The polyp along with the short segment of the ureter was resected. Diagnostic and therapeutic considerations are discussed.

Child, Preschool↗
PubMedDate not supplied

[AIDS help--evaluation of a public health movement].

The "AIDS-Hilfe" movement-more than 80 local groups are presently united in the Federal German organization of the "Deutsche AIDS-Hilfe e. V." -looks back at a more than five years of experience in the fields of prevention for different target groups, counselling, care, PR-work and representation of interests. Central point of the concept of prevention of "AIDS-Hilfe" is the unprejudiced acceptance of people with HIV/AIDS and people at risk: homosexuals, i. v. drug users, prison inmates, haemophiliacs, and people who are not monogamous. A promising AIDS prevention is confronted by various difficulties: there are waves of hysteria, there is a lack of grants from Federal funds, there is moralizing instead of taking effective measures in health policy, there is a tendency to bureaucratize, there is a restrictive legal approach to the problems of AIDS, etc. In contrast to the good results prevention has already achieved in the group of homosexual men, is a farreaching ignorance and inhumanity on the part of political and administrative authorities in matters of drug use and imprisonment. The paradigm of abstinence is responsible for i. v. drug users to contract AIDS, because low-threshold measures, such as needle-exchange programmes and drug-substitution programmes, are refused. To remind the public this fact constantly and to fight for it will be a major concern of the "AIDS-Hilfe" movement. It must always be borne in mind that "principles" are secondary and that human beings must come first.

Acquired Immunodeficiency Syndrome↗