Oliver W. Jones

Mexican immigrants and the utilization of U.S. health services: The case of San Diego

This paper examines survey data gathered from 2103 Mexican immigrants living or working in San Diego County, California, in order to explore four fundamental questions concerning the utilization of health services: (a) What type of health services do Mexican immigrants use? (b) When hospitals are used, do they tend to be emergency room services? (c) Do Mexican immigrants use preventive services? (d) To what extent do the utilization patterns of undocumented immigrants differ from their legally-immigrated counterparts? The socioeconomic profile of the sample is characterized through analysis of variables such as sex, age, length of residence in the U.S., occupation and income. Mexican immigrants, particularly the undocumented, are relatively young compared to the non-immigrant population, of short duration in the U.S. and earn low income. In addition, undocumented and legally-immigrated respondents are covered by medical insurance at rates far below the general population. Mexican immigrants, including the undocumented, use a variety of health services. Hospital services are not the primary source of care. However, when undocumented respondents did use hospital services, they were more likely to use emergency room care than their legally-immigrated counterparts, who were more likely to use out-patient services. Finally, undocumented respondents tended to neglect preventive services as evidenced by examination of the use of pre-natal care, general check-ups and dental services.

Characterization of human cystathionine β-synthase: Evidence for the identity of human l-serine dehydratase and cystathionine β-synthase

Abstract A protein has been studied in human fetal liver that is able to condense serine with several sulfur donors. The two activities of greatest interest are cystathionine β-synthase (EC 4.2.1.22) which catalyzes the reaction of sulfide with serine to form cysteine, and l -serine dehydratase (EC 4.2.1.13) which condenses homocysteine with serine to form cystathionine. These two activities were followed through several purification steps and were always found in the same fractions. The ratio of the activities remained constant at 1.7 ± 0.1 with homocysteine as the preferred sulfur donor. When the two activities were assayed simultaneously, sulfide did not interfere with cystathionine synthesis, but a sulfide-to-homocysteine ratio of at least 1.5 was needed for cysteine production. Both activities showed similar thermal denaturation profiles and sensitivity to hydroxalamine. Further evidence that these activities are associated with the same protein comes from the observation that a patient with homocystinuria is deficient in cystathionine β-synthase as well as l -serine dehydratase.

Prenatal diagnosis of trisomy 9

SummaryA male karyotype with trisomy 9 (47,XY,+9) was identified in amniotic fluid cells from a 40-year-old pregnant woman. After termination of the pregnancy by saline abortion, the cytogenetic diagnosis was confirmed in a cell line grown from placental tissue. Microscopic and gross pathological findings in the fetus were compared to 1 case with trisomy 9 and 3 with trisomy 9 mosaicism reported in the literature. A distinct clinical syndrome appears to be associated with this rare autosomal trisomy.

The presence of “fetal” thymidine kinase in human tumors

Abstract We have recently discovered that human fetal thymidine kinase has physical properties clearly distinguishable from human post-natal thymidine kinase. The fetal enzyme activity appears to be related to rapid growth of fetal tissues. The same enzyme is observed in two permanent human tumor cell lines. In this report we demonstrate that several malignant human tumors contain predominantly the fetal form of thymidine kinase. It is possible that fetal gene expression of thymidine kinase may have an important relationship to altered cell growth in human adult tissues.

Fetal exsanguination and other vascular injuries from midtrimester genetic amniocentesis.

A case of fetal exsanguination after midtrimester genetic amniocentesis is reported. Examination of the ration of fetal-to-meternal red cells in the amniotic fluid obtained by amniocentesis for genetic study from 242 consecutive patients, including the reported case, suggests that fetal hemorrhage is relatively common and difficult to avoid during this procedure. It also appears that hemorrhage occurs significantly more oftern when the placenta is located anteriorly. Reasons as to why the accident is rarely fatal are considered, and some recommendations for patient counselling and management are discussed.

Use of nude mouse xenografts as preclinical screens: Characterization of xenograft-derived melanoma cell lines

Cell lines derived from human melanoma xenografts were characterized for surface markers, karyotype abnormalities, and in vitro drug sensitivity. Xenografts were established using metastatic explants from untreated patients and passaged in nude mice. Cell lines were readily established from melanoma xenografts, and formed colonies when plated in semisolid media. The lines expressed human melanoma‐associated and other surface antigens, human lactate dehydrogenase (LDH) isoenzymes, and contained only human chromosomes. They failed to express murine histocompatibility determinants and were negative for murine viruses by mouse antibody production assay. Karyotypes showed abnormalities of chromosomes 3, 6, and 7 similar to other melanomas. In vitro chemósensitivity profiles were compared using cell line and xenograft colony‐forming assays. Values were similar for the original xenografts and their cell lines. Xenograft‐derived human melanoma lines resemble other melanoma cell lines and primary melanomas with respect to surface antigens and karyotype abnormalities, and are appropriate models for studying in vitro drug sensitivity. When used as a model for transition from solid tumor to cell line, these studies suggest cell lines closely mirror in vitro chemosensitivities of parent tumor cells. However, occasional, unpredictable changes in sensitivity to some drugs occurs during this transition.

Neural origin of cells in amniotic fluid

Cells from the amniotic fluid of fetuses with open neural tube defects (NTDs) have several abnormal characteristics of potential diagnostic value. The cell number in a unit volume of fluid is 10 to 100 times the normal range of cell count. The majority of cells adhere to tissue culture dishes within 24 hours of inoculation, instead of the 4 or 5 days required by normal amniotic fluid cells. The rapidly adhering cells morphologically resemble glial cells. Their Coulter volume is about twice the average seen in normal amniotic fluid--derived cells. This larger number of oversized, rapidly adhering cells is likely due to the continuous accumulation of neural cells in the amniotic fluid. We have detected the presence of the glial protein S-100 and the absence of the neuronal protein 14-3-2 by using a specific immunofluorescence assay. We conclude that fetuses with NTDs shed large numbers of glialike cells into the amniotic fluid where their detection may have diagnostic importance.

Complete hydatidiform mole with a coexistent embryo

We describe a case of a complete hydatidiform mole with a coexistent embryo. A 19-year-old Hispanic woman presented with an intrauterine pregnancy at 7 weeks gestational age. An ultrasound evaluation at that time showed a gestational sac and fetal heart activity was observed. Four weeks later, subsequent ultrasound study revealed no evidence of an embryo, and a pattern consistent with a hydatidiform mole. Dilation and curettage was subsequently performed that showed a classic hydatidiform mole on histological examination. Chromosome analysis revealed a normal 46,XX karyotype. DNA was extracted from the placental tissue, as well as maternal and paternal blood. Molecular genetic analysis was; performed with four variable number of tandem repeats (VNTR) probes and showed the placental tissue to consist of only paternal DNA with two genomic copies of each allele studied. These findings are consistent with the diagnosis of complete hydatidiform mole and its origin from an empty ovum fertilized by a single sperm. This is the first reported case of a living embryo coexistent with a complete hydatidiform mole documented by genetic analysis.

Amniocentesis for antenatal diagnosis: Review of problems and outcomes in a large series

The results of amniocentesis for diagnostic genetic studies on 242 patients are presented in detail. These suggest that obtaining fluid free from contaminating red blood cells is important to successful cell culture. The data also suggest that it is technically more difficult to obtain such fluid tham might be expected, despite the use of ultrasonic localization and experienced operators. Nevertheless, 97 per cent of patients who elect to complete antenatal diagnosis will ultimately obtain the information sought, in time to intervene medically if desired. Moreover, the act of obtaining this information is shown to be without significant risk to the ultimate outcome of pregnancy.

Expanded care in obstetrics for the 1980s: Preconception and early postconception counseling

This paper is an essay in which the suggestion is made to expand obstetric care during this decade to include preconception as well as early postconception counseling. The development of perinatal and neonatal medicine is traced and medical problems that might be improved by medical counseling before pregnancy occurs are tabulated. Diabetes is suggested as a prototype of a medical disorder for which preconception counseling would be helpful. The expansion of obstetric services into an area of preventive medicine might well begin in already established regional medical centers but should quickly expand to the offices of private obstetricians. In this broader interpretation of obstetric care, prevention of maternal and fetal or neonatal problems could decrease the cost of high-risk medical care.