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Biomedical subjects

D S Mack

Publications and source records attributed to D S Mack.

9 recordsLinked to original sources
PubMed1989

The stability and short-term fluctuation in serum oxytocinase activity in pregnancy.

Maternal serum samples obtained from 123 normal pregnant women between 28 and 40 weeks gestation were analysed for oxytocinase (EC 3.4.11.3) activity using s-benzyl-1-cysteine-4-nitroanilide as substrate. Oxytocinase activity was found to be stable at varying temperatures, with a mean co-efficient of variation of 5.0%. The short-term fluctuation of oxytocinase activity had a mean coefficient of variation of 3.6%. There is no suggestion of a "pulsatile" release of oxytocinae from its placental origin.

Aminopeptidases↗
PubMed1984

Enzyme immunoassay for pregnancy-associated plasma protein-A.

This enzyme immunoassay procedure for pregnancy-associated plasma protein type A involves a "sandwich"-type system in microtitration plates. One can detect 0.27 mg of the protein per liter of serum, with a between-batch CV of 10.2%, and the antiserum used does not cross react with any of the other placentally derived proteins. A reference interval for the last trimester of pregnancy is presented. The procedure described is suitable for studying the behavior of this protein during pregnancy.

Cross Reactions↗
PubMed1983

A prospective study of three biochemical fetoplacental tests: serum human placental lactogen, pregnancy-specific beta 1-glycoprotein, and urinary estrogens, and their relationship to placental insufficiency.

The relationship between abnormal biochemical fetoplacental test results and placental insufficiency was studied in a group of high-risk obstetric patients. The urinary estrogen: creatinine ratio and serum human placental lactogen (hPL) and pregnancy-specific beta 1-glycoprotein (SP1) were measured in more than 1,600 patients. Fifty-one patients were found to have abnormal biochemical results, and the placentas from these patients were sent for the assessment of placental insufficiency by pathologic examination, which was expressed as a placental insufficiency score. Low hPL was found to be the best biochemical indicator of placental insufficiency, and 84% of the patients with a low level of hPL had an elevated placental insufficiency score. The combination of low levels of hPL and urinary estrogen was found to be the best indicator of placental insufficiency associated with retarded intrauterine growth, and 83% of the patients who had low results in both of these tests had elevated placental insufficiency scores and were delivered of light-for-dates infants. The measurement of SP1 was found to be of limited value in detecting retarded growth, but patients with low SP1 values showed an increased incidence of fetal hypoxia. Attention is drawn to the fact that the discrepancies that occur in the various estimations are not necessarily due to artifact, and specific pathologic processes which could account for some of the anomalous results are identified.

Apgar Score↗
PubMed1980

Effects of age, sex, and reproductive status on scent marking frequencies in the golden lion tamarin, Leontopithecus rosalia.

This study reports on the longitudinal changes in scent marking frequencies of male and female lion tamarins in relation to age, reproductive status, and group composition. Juvenile males and females in family groups and subordinate males in trios (2 males, 1 female) scent marked infrequently. Juvenile females scent marked less than juvenile males and began scent marking later. Adult pair-bonded males and females scent marked with similar frequencies. Females showed scent marking increases during mid-pregnancy, but their scent marking decreased both before and again after parturition. Both males and females exhibited decreases in scent marking while transporting dependent infants.

Age Factors↗
PubMed1980

Enzyme-linked immunoassay for placental lactogen in human serum.

We describe an enzyme-linked immunoassay for measuring human placental lactogen (HPL) in serum. After suitable dilution, sera are pipetted into the wells of polyvinyl microtitre plates previously coated with anti-HPL. After incubation the sera are decanted, and replaced by a conjugate of horseradish peroxidase and anti-HPL. An amount of enzyme proportional to the concentration of HPL in the serum is bound to the wells via an antibody--HPL--antibody bridge. Peroxidase activity is measured by oxidation of o-phenylenediamine, the resulting color being related to the concentration of HPL. Results correlate well with those by radioimmunoassay (r = 0.96). Our between-assay coefficient of variation was 13%; no discernible effect of protein was observed. This 4-h assay can be used to monitor placental function in pregnancy.

Evaluation Studies as Topic↗
PubMed1978

Food sharing among captive Leontopithecus rosalia.

Captive L. rosalia were observed to exchange food routinely in family groups, a process varying from donation to theft. Donation involved the use of 'invitational' signals which operated most efficiently in parent-infant sharing and in donating live prey. Food moved, by sharing and theft, toward: (a) males prior to the female's first conception; (b) females during late pregnancy; (c) carriers of infants; (d) weanlings; (e) juveniles when infants died; (f) third animals in trios, regardless of their age and relatedness to the pair. Successful reproduction, a complex behavior involving all group members in cooperative infant care and provisioning, is probably enhanced by captive L. rosalia's food-sharing habits.

Animals↗