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Biomedical subjects

M C Pike

Publications and source records attributed to M C Pike.

At least 307 records · Page 17Linked to original sources
PubMed1976

Depression of macrophage function by a factor produced by neoplasms: a merchanism for abrogation of immune surveillance.

The possibility that macrophages mediate surveillance against the development of neoplasms has been reciving increasing support. The acquisition, by neoplastic cells, of the capacity to subvert macrophage function may be an important mechanism by which they escape destruction by the host and become established tumors. Indeed, animals implanted with syngeneic neoplasms developed depressed macrophage migratory ability in vivo and chemotactic responsiveness in virto. It therefore seemed plausible that neoplasms might be capable of producing inhibitors of macrophage function. The present report describes the identification of such a low molecular weight (6,000 to 10,000), heat-stable inhibitor of murine macrophage accumulation in vivo and chemotaxis in vitro. The inhibitor of macrophages was present in four different murine neoplasms, but not present in normal liver, spleen, or inflammatory exudate cells and did not affect PMN chemotaxis in vitro. When given with low numbers of neoplastic cells, the inhibitor increased both the frequency of tumor development and rate of tumor growth. By producing inhibitors of macrophage function, neoplasms may escape initial host surveillance mechanisms.

Animals↗
PubMed1976

Generalisations of two tests for the detection of household aggregation of disease.

Two statistical tests have been suggested to detect household aggregation of disease. Mathen and Chakraborty [1950] proposed counting the number of households, Z, in which there were no cases of the disease, and Walter [1974] proposed counting the number of pairs, N, of cases within households. As originally formulated, both of these methods suffer from the limitation that it is assumed, in the null case, that all members of the population, who are assumed to be susceptible, are at equal risk to disease. In this paper we generalise these tests to the situation in which different population strata are at different risks to disease. Formulae are given for the first four moments of Z. The revised Walter's test is shown to be a special case of a test of Pike and Smith [1974] which enables the expectation and variance of N to be directly evaluated. A similar relationship is noted between Walter's test and Knox's [1964] test for space-time clustering. A further test statistic is suggested: the number of cases, T, in households containing two or more cases.

Brazil↗
PubMed1975

Elevated serum levels of estrogen and prolactin in daughters of patients with breast cancer.

Demographic risk factors in sisters and daughters of 150 patients with breast cancer were compared to those of controls. Plasma hormone levels in 36 teen-age daughters of patients and 31 controls were also studied to ascertain whether an "abnormal" hormone pattern underlies these risk factors. The patients' sisters had, on the average, menarche four months earlier and first full-term pregnancy 12 months later than the controls. The patients' daughters did not show these differences -- apparently owing to low fertility in the patients with early menarche. The patients' daughters had higher 22d-day estradiol-plus-estrone levels than controls (24.4 vs. 19.1 ng per 100 ml, P less than 0.05). Sixth-day prolactin was also elevated (19.0 vs. 14.2 ng per 100 ml, P less than 0.05). About half the patients' daughters could clearly be distinguished from the controls' daughters by means of the sixth-day information on both estrogens and prolactin. Hypersecretion of these hormones may be important factors in breast cancer.

Adolescent↗
PubMed1975

Reserpine and breast cancer in a retirement community.

In an attempt to confirm three reports suggesting a causal link between rauwolfia antihypertensive drugs and female breast carcinoma, all cases of such cancer appearing among the residents of an affluent retirement community were compared with controls chosen from a roster of all women in the same community. Most residents use a single care facility, and patterns of hypertension diagnosis, rauwolfia and other drug use, and medical-care-system patronage were abstracted from medical records. The prevalence of recorded rauwolfia use among the controls were 20 per cent, and that of other drug use was correspondingly high. The risk ratio for rauwolfia use was estimated to be 1.2 (95 per cent confidence interval, 0.7 to 2.2). Risk ratios between 1.0 and 2.0 were also found for other drug use and for measures of care-system patronage. These results do not support the hypothesis that reserpine causes breast cancer.

Aged↗
PubMed1975

The influence of chemotherapy on the prognosis of rhabdomyosarcoma.

A study of 77 consecutive cases of childhood rhabdomyosarcoma treated initially at the Children's Hospital of Los Angeles from 1950 to 1972 demonstrated an impressive improvement in survival of patients when intensive chemotherapy was occurred in Stage II and Stage III disease. Eight out of 9 patients with a primary lesion of the lower extremities developed intra-abdominal disease. A general approach for treatment of Stage II, III, and IV rhabdomyosarcoma is proposed which involves intensive chemotherapy, following biopsy, as the principle treatment, with radiation and surgery used as a adjuvants.

Adolescent↗
PubMed1975

Cancer incidence in the Mexican-American.

Lower incidence rates of cancer for all anatomic sites combined were found in male and female Spanish-surnamed residents of Los Angeles County when compared to other whites. These Mexican-Americans were at lower risk for cancer of the buccal cavity, colon, rectum, larynx, lung, breast, bladder, prostate, and testis, and were at higher risk for cancer of the stomach, gallbladder, liver, and cervix. Immigrant Mexican-Americans had incidence rates most divergent from other whites, whereas indigenous Mexican-Americans had rates between the other two groups. The cancer pattern in Mexican-Americans was generally similar to that in American Indians. These data were most consistent with environmental variations in cause.

Adolescent↗
PubMed1975

Lung cancer and air pollution in southcentral Los Angeles County.

An increased rate of lung cancer has been consistently observed from 1968-1972 among males in southcentral Los Angeles. This excess risk occurs across several social classes and occupational categories. No differential excess of oral cavity, pancreatic, laryngeal and bladder cancer was observed in the same area, lessening the possibility that regional variations in smoking habits accounted for the excess lung cancer. Air sampling has indicated an excess of certain polynuclear aromatic hydrocarbons (PAH) in southcentral Los Angeles. There was a correlation between the geographic distribution of lung cancer cases and the general location of industries which have emitted these PAH. A case-controlled study of smoking, occupational and residential history in the southcentral area is underway.

Adult↗
PubMed1975

Interaction of complex polysaccharides with the complement system: effect of calcium depletion on terminal component consumption.

Complex polysaccharides and lipopolysaccharides can activate the terminal components of complement by either the classical (antibody, C1, C4, and C2) or alternative complement pathways, but the relative importance of either pathway for terminal component consumption in normal serum is poorly understood. Since classical complement pathway function requires both calcium and magnesium ions, whereas the alternative pathway requires only magnesium ions, selective chelation of calcium ions in serum can be used to block the classical complement pathway while leaving the alternative pathway intact. In these studies, ethyleneglycol-bis-(beta-aminoethyl ether)N, N-tetraacetic acid, a potent chelator or calcium, was used to block the classical complement pathway in normal guinea pig serum. Consumption of the terminal complement components by endotoxin, inulin, and zymosan in such serum was strikingly depressed when compared to serum containing an intact classical complement pathway. These studies demonstrate that in normal serum, both the classical and alternative complement pathways participate in the consumption of the terminal complement components by complex polysaccharides and lipopolysaccharides.

Animals↗
PubMed1975

Quantification of mouse macrophage chemotaxis in vitro: role of C5 for the production of chemotactic activity.

Delineation of the mechanisms of macrophage accumulation at local tissue sites will further our understanding of immunologically mediated host resistance to infectious and neoplastic diseases. Since mice are frequently used for the study of immune function, we developed a method for the quantification of mouse macrophage chemotaxis in vitro. By this method it was found that the fifth component of complement is necessary for the production of chemotactic activity in mouse serum by inflammatory agents such as endotoxin or aggregated gamma globulin. The majority of macrophage chemotactic activity produced by these agents in mouse serum can be attributed to a low-molecular-weight (ca. 15,000) chemotactic factor. The data suggest that this factor is the biologically active cleavage product of the fifth component of complement, C5a.

Animals↗
PubMed1975

Statistical analysis of individually matched case-control studies in epidemiology: factor under study a discrete variable taking multiple values.

It is now well established in case-control studies with individual matching that the statistical analysis must take the fact of individual matching into account. The problems of so doing have been thoroughly dealt with for the situation of the factor of interest being a two-level factor (all-or-none response) and with one or more matched controls per patient. These results are extended in this paper to the situation where the factor can assume multiple levels in studies where each patient is matched with a single control.

Age Factors↗