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J Mandel

Publications and source records attributed to J Mandel.

At least 37 records · Page 2Linked to original sources
PubMed1981

A multilaboratory-evaluated reference method for the determination of serum sodium.

We carried out a statistically designed, multilaboratory study to evaluate a flame atomic emission spectroscopic (FAES) method for serum sodium as a Reference Method. definitive values for the serum pools for the study, with sodium in the 110-160 mmol/L range, were determined at the National Bureau of Standards by an ion-exchange/gravimetry method. The multilaboratory FAES results were judged against the preselected performance criteria for the Reference Method: maximum imprecision 1.5 mmol/L, maximum bias 2.0 mmol/L. The standard error of a single laboratory's performance of the method varied with concentration from 0.46 to 0.86 mmol/L with a maximum bias of 1.0 mmol/L; thus, the criteria were satisfied. The cooperating laboratories performed the method with either manual or semi-automated pipetting. Although both modes of pipetting satisfied our acceptability criteria, only the method with semi-automated pipetting is described here as the Reference Method. The statistical results indicate that the precision criterion can be fulfilled with fewer than four replicate analyses.

Humans↗
PubMed1980

DAWN: a second look--its impact on minorities and public policy.

Though various indicators yield different statistics about the minority component of drug problems, Blacks and Hispanics dominate opiate statistics of major data systems. This dominance increases when major consequences--chemotherapy, arrest and, especially, imprisonment--are measured. Drug Abuse Warning Network (DAWN) figures were cited as the exception, but this was due to weaknesses in DAWN reporting and its analysis by experts. Excluding unreliable and unrepresentative crisis center mentions, estimating the Hispanic component of "White" DAWN mentions, and separating opiates from other drugs, the DAWN statistics are very similar to CODAP and arrest statistics. "Hard drugs" remain an essentially minority phenomena.

Black or African American↗
PubMed1980

Statistics blur minority distinctiveness.

In their study of the success of drug treatment, Sirotnik and Roffe blurred and probably minimized racial and ethnic distinctions. Their problem was trying to compare Whites, Blacks, and Chicanos with a statistic requiring two-art or scalar variables. Of non-Blacks (compared to Blacks), 29% were Chicanos, and of non-Browns (compared to Chicanos), 32% were Blacks. Nonetheless, of nine variables significantly associated with "staying in treatment," five were blackness, brownness, or synonymous with them. A format with only percentages would enable analysis to see substantive results clearly and in more detail.

Ethnicity↗
PubMed1980

Total serum cholesterol by isotope dilution/mass spectrometry: a candidate definitive method.

We describe a highly accurate and precise method for determination of total cholesterol in serum by isotope dilution/mass spectrometry. The method was developed for a Study Group of the Committee on Standards of the American Association for Clinical Chemistry, for use in establishing the accuracy of a candidate reference method for total cholesterol, and fulfills their criteria for a definitive method. Cholesterol-d7 is added to serum, with the weight ratio of cholesterol-d7 to total serum cholesterol kept near to 1:1. The esters are hydrolyzed and the cholesterol is separated and converted into the trimethylsilyl ether derivative for measurement by combined gas chromatography/mass spectrometry. The intensity ratio of the molecular ions at m/z 465 and 458 is measured for each sample and for two calibration mixtures, according to a prescribed bracketing protocol. A weight ratio for the sample is obtained by linear interpolation of the ion-intensity ratios, and the total cholesterol is then calculated. The method was applied four times over several weeks to each of five serum pools. Statistical analysis involving consideration of both replication error and variability between weeks gave a coefficient of variation for a single measurement of 0.36%. The absence of interferences in the method was demonstrated by measurements at several other masses.

Carbon Radioisotopes↗
PubMed1980

The parameterization of predictive value for multisite screening.

In the design of a medical screening program, it is standard practice to employ the parameters of sensitivity and specificity of the test, together with the population disease prevalence, in order to obtain the predictive values of the test. Multiphasic screening, i.e. the use of two or more tests on the same occasion to screen for more than a single disease, has stimulated the need for a formulation of the joint predictive value of these tests employed in combination. In this communication a parameterization of joint predictive value is presented in the context of multisite cancer screening. The resulting parameters are related to the separate disease prevalences, as well as to the sensitivities and specificities of the separate tests, under the assumption of statistical independence among cancer screens.

Humans↗
PubMed1978

Statistical evaluation of CAP survey results for calcium, potassium, and blood urea nitrogen.

Throug the use of the statistical technic known as the linear model, a complete analysis has been made of data obtained in the Colleg of American Pathologists Survey of 1975 for calcium, potassium, and blood urea nitrogen (BUN). The analysis allows a separation of laboratories into core and non-core categories. It also allows for determination of the reproducibility of each analytic technic involved in this survey. For Ca and K, the results obtained by each analytic method were compared with the results obtained by the National Bureau of Standards through use of the definitive method. For BUN, the comparison was made with the average of values for all laboratories and all methods.

Blood Urea Nitrogen↗
PubMed1976

Investigating possible effects of abestos in city water: surveillance of gastrointestinal cancer incidence in Duluth, Minnesota.

The recent discovery of over one million asbestos-like fibers per liter of Duluth tap water and the suggestive evidence of a link between certain gastrointestinal (GI) cancers and work exposure to asbestos fibers in the air prompted this study. GI cancer incidence data were gathered for Duluth in the same manner as data previously gathered for comparison cities, Minneapolis and St. Paul. Although some differences in GI cancer incidence occurred among the three cities in 1969-1971, there was no consistent pattern of statistically significant differences observed. The number of GI cancers diagnosed in Duluth residents in 1972 was similar to that in each of the previous three years. This study represents the start of ongoing cancer surveillance in Duluth.

Age Factors↗
PubMedDate not supplied

Are lower penalties a green light for drug users?

It is probable that DAWN reporters have become more thorough over the years and that the police have become more active in the drug arena during the first half of the 1980's. If this is in fact the case, both sets of statistics would suggest that marijuana use has declined while the use of other illegal drugs, for which possession is penalized as heavily as ever, has risen substantially--although not quite so much as the statistics imply. In sum, the two best statistical indicators of drug use in California show that lowering penalties for marijuana possession did not cause a rise in the use of that drug. On the contrary, these indicators point to a stable situation regarding marijuana use in the decade after the implementation of the Moscone Act, while the use of other illegal drugs soared.

Humans↗
PubMedDate not supplied

A spreadsheet for AIDS: estimating heterosexual injection drug user population size from AIDS statistics in San Francisco.

A single-page computer spreadsheet can be used to back-calculate the size of the population at risk from the reported number of AIDS cases and HIV seropositivity levels for that population. However, Cohen (1988:35) has cautioned that "this method requires some heroic assumptions, and is, therefore, fraught with difficulty." Slight variations in the definition of AIDS, in the progression rate, and in reported seropositivity rates used as data in the spreadsheet can make enormous differences in the results obtained through back-calculation. Despite the limitations of the method, an estimate of the possible size of the IDU population can be derived from back-calculation, with careful consideration of ethnographic realities taken into account. In San Francisco, the present authors believe that there were approximately 13,000 heterosexual IDUs as of the end of 1989. Further demographic divisions by ethnicity, age, sex, and even neighborhood could be made using the same techniques, if AIDS cases and seropositivity levels could be obtained for each variable. Table II predicts a cumulative 705 AIDS diagnoses among San Francisco heterosexual IDUs by the end of 1993, or nearly six times as many as reported through 1988. This prediction is based on an assumption of 2.5% seroconversion per year (1989-1993) and on modest progression-rate increments of 5%, 5%, 4%, 3%, and 3% in the eleventh through fifteenth years after HIV infection. Thus, it shows the magnitude of the epidemic that San Francisco will shortly face and emphasizes the need to act vigorously to prevent further HIV contagion among IDUs as well as from them to their heterosexual partners (drug using or not).(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Providing medical marijuana: the importance of cannabis clubs.

In 1996, shortly after the San Francisco Cannabis Club was raided and (temporarily) closed by state authorities, the authors conducted an ethnographic study by interviewing selected former members to ascertain how they had benefited from the use of medical marijuana and how they had utilized the clubs. Interviews were augmented by participant observation techniques. Respondents reported highly positive health benefits from marijuana itself, and underscored even greater benefits from the social aspects of the clubs, which they described as providing important emotional supports. As such, cannabis clubs serve as crucial support mechanisms/groups for people with a wide variety of serious illnesses and conditions. The authors concluded that of the various methods so far proposed, the cannabis clubs afford the best therapeutic setting for providing medical cannabis and for offering a healing environment composed of like-minded, sympathetic friends.

Cannabis↗
PubMedDate not supplied

Epidemiologic study of prostatic cancer: preliminary report.

In a preliminary report on a small fraction of the projected subject population, some evidence in support of both sexual activity and venereal transmission hypotheses is accumulating. Prostatic cancer cases, in contrast to hospitalized and/or neighborhood controls, are beginning to show greater proportions of selected sexual activities compatible with venereal transmission of an infectious agent, such as number of sexual partners, use of prostitutes, prior venereal disease, and genital infections in the spouse. Patients with prostatic cancer also appear to have had higher fertility and more prostatic cancer in blood relatives than controls. Age at first intercourse and at first marriage are lower among the cancer patients than among the controls. Antibody titrations for herpesvirus and cytomegalic virus, although currently not revealing striking disparities in positivity, tend to show higher titers among the cancer cases.

Adult↗