The carotid bodies influence growth responses to moderate maternal undernutrition in late-gestation fetal sheep.

OBJECTIVE: To determine the role of carotid sinus innervation on differential fetal organ growth during maternal nutrient restriction in late pregnancy. DESIGN: Randomised controlled study. SETTING: University research facility. SAMPLE: Thirty-nine Merino ewes. METHODS: At 113 days gestational age (dGA), fetuses were bilaterally carotid sinus denervated or sham denervated. From 118 dGA, the surgery groups were subdivided into two dietary groups, and their ewes were fed 100% of nutrient requirements or 50% until tissue collection at 140 dGA. This provided four groups (sham/control diet, sham/restricted diet, denervated/control diet and denervated/restricted diet). MAIN OUTCOME MEASURES: Fetal organ weights and hormone levels and maternal weight change during the dietary restriction. RESULTS: Adrenal glands were larger in sham/restricted diet fetuses than in sham/control diet or denervated/restricted diet fetuses (P < 0.05). Fetal adrenal weight and brain-to-liver weight ratio were positively related to maternal weight change during the nutritional challenge in sham fetuses only (P < 0.05). Fetal liver weight was negatively related to maternal weight change during nutritional challenge in sham fetuses only (P < 0.05). CONCLUSIONS: We have shown a reduction in liver growth but sparing of adrenal growth in response to moderate maternal undernutrition, which is dependent on intact carotid body innervation. This suggests a new role for the carotid bodies in the control of differential organ growth during such undernutrition.

Sensitive detection of rare circulating neuroblastoma cells by the reverse transcriptase-polymerase chain reaction.

The presence of circulating tumor cells in patients with localized or disseminated neuroblastoma may be a significant prognostic factor at diagnosis and may antedate the detection of relapse by other diagnostic studies. We report the development of a highly sensitive detection assay for circulating neuroblasts based on the reverse transcriptase-polymerase chain reaction (RT-PCR), using the neuroendocrine protein gene product 9.5 (PGP 9.5) as the tumor marker. Analysis of RT-PCR products by agarose gel electrophoresis demonstrated that neuroblastoma cell lines were uniformly positive, whereas peripheral blood mononuclear cells were negative. Alkaline Southern blotting with a PGP 9.5-specific probe revealed scant expression of PGP 9.5 in peripheral blood mononuclear cells, well below the limits of detection by electrophoresis alone. The system was able to detect a single neuroblastoma cell in 10(7) peripheral blood mononuclear cells. Eighteen patient samples were analyzed by PGP 9.5 RT-PCR and the results compared with immunocytology in 16. Ten of the 18 were negative by both studies. Eight of the 18 were positive by PGP 9.5 RT-PCR, 4 of which were also positive by immunocytology. PGP 9.5 RT-PCR was able to detect circulating neuroblasts in two patients with negative immunocytology, the first with progressive bone marrow disease and the second at high risk for relapse but no other evidence of disease. PGP 9.5 RT-PCR allows the detection of circulating neuroblastoma cells with a sensitivity greater than immunocytology. It will be useful in evaluating the clinical significance of circulating tumor cells with respect to prognosis and early detection of relapse, and in the screening of peripheral stem cell harvests prior to autologous infusion.

A review of fundamental principles for animal models of DOHaD research: an Australian perspective.

Epidemiology formed the basis of 'the Barker hypothesis', the concept of 'developmental programming' and today's discipline of the Developmental Origins of Health and Disease (DOHaD). Animal experimentation provided proof of the underlying concepts, and continues to generate knowledge of underlying mechanisms. Interventions in humans, based on DOHaD principles, will be informed by experiments in animals. As knowledge in this discipline has accumulated, from studies of humans and other animals, the complexity of interactions between genome, environment and epigenetics, has been revealed. The vast nature of programming stimuli and breadth of effects is becoming known. As a result of our accumulating knowledge we now appreciate the impact of many variables that contribute to programmed outcomes. To guide further animal research in this field, the Australia and New Zealand DOHaD society (ANZ DOHaD) Animals Models of DOHaD Research Working Group convened at the 2nd Annual ANZ DOHaD Congress in Melbourne, Australia in April 2015. This review summarizes the contributions of animal research to the understanding of DOHaD, and makes recommendations for the design and conduct of animal experiments to maximize relevance, reproducibility and translation of knowledge into improving health and well-being.

Detection of neuroblastoma cells in blood.

Tumor surveillance tests are used to detect relapse and to guide the clinician in making therapeutic changes. Identification of relapse early in the course of disease may improve long-term survival. For patients with neuroblastoma, current conventional surveillance methods include radiologic testing, bone marrow analysis, physical examination, and measurement of urinary catecholamine metabolites. Immunocytologic analysis of blood for the detection of circulating tumor cells is a highly specific and sensitive method, which may prove useful in monitoring patients with neuroblastoma. In our study, circulating tumor cells were detected in seven of 10 patients with known disseminated disease at diagnosis and in six of 13 patients during therapy. In some patients, as few as two tumor cells were identified among 100,000 normal hematopoietic cells. The presence or absence of circulating neuroblasts in the 13 patients evaluated during therapy was significantly correlated with tumor relapse (P = .002). We conclude that immunocytologic analysis of blood is a sensitive method for the detection of circulating neuroblasts. We recommend that this technique be used in conjunction with other conventional methods for improved tumor detection and subsequent monitoring of neuroblastoma patients.

Occult tumor contamination of hematopoietic stem-cell products does not affect clinical outcome of autologous transplantation in patients with metastatic breast cancer.

PURPOSE: To determine whether occult tumor contamination of autologous bone marrow or peripheral-blood progenitor cells (PBPC) influences clinical outcome after high-dose chemotherapy in patients with stage IV breast cancer. PATIENTS AND METHODS: We used an immunocytochemical assay capable of detecting one tumor cell in 5 x 10(5) hematopoietic cells to analyze bone marrow and/or PBPC collections obtained from 57 consecutive women with chemotherapy-sensitive metastatic breast cancer who received high-dose chemotherapy. The influence of occult tumor on time to progression, overall survival, and first site of recurrence (old or new) was studied. RESULTS: Twenty-three of 57 (40%) patients received bone marrow (n=6) or peripheral-blood progenitor collections (n=17) that contained microscopic cancer. Median time to progression and overall survival were 9 and 22 months in patients who did not receive infused tumor cells, compared with 10 and 24 months, respectively, in those who received occult tumor (P=not significant [NS]). Worse survival, but not time to progression, was observed in six patients who received > or = 2/100,000 tumor cells. Regardless of whether occult tumor was infused, the majority of relapses occurred in prior, rather than new sites of disease. Three patients who received stem-cell products contaminated by microscopic breast cancer remain free from progression at 21+, 47+, and 52+ months. CONCLUSION: Microscopic tumor was frequently detected by immunocytochemistry in hematopoietic stem-cell products, but did not predict for inferior treatment outcome in this cohort of patients with metastatic breast cancer. Quantitative information regarding infused tumor burden may have prognostic significance.

Similar breast cancer cell contamination of single-day peripheral-blood progenitor-cell collections obtained after priming with hematopoietic growth factor alone or after cyclophosphamide followed by growth factor.

PURPOSE: To evaluate tumor-cell contamination of peripheral-blood progenitor-cell (PBPC) collections obtained after priming with granulocyte colony-stimulating factor (G-CSF). PATIENTS AND METHODS: Immunocytochemical (ICC) and tumor clonogenic (TCA) assays were used to analyze tumor-cell contamination of pretreatment peripheral-blood (PB) and bone marrow (BM) samples, and of PBPC collection samples obtained after priming with G-CSF 5 micrograms/kg/d for 5 or 7 days in 38 women with advanced breast cancer undergoing high-dose chemotherapy (HDC). Results were compared with 37 historical control patients who underwent PBPC mobilization with cyclophosphamide (4 g/m2) followed by granulocyte-macrophage colony-stimulating factor (GM-CSF) 5 micrograms/kg/d for 14 days. RESULTS: Before PBPC priming with G-CSF, only one of 37 (3%) PB and four of 36 (11%) BM samples had tumor cells detected by ICC. Tumor-cell contamination of PBPC collections obtained after 5 or 7 days of G-CSF priming was observed in only three of 38 patients (8%). All patients with tumor cells detected in the PBPC collection had stage IV disease. Cells with in vitro clonogenic potential were detected only in the pretreatment BM sample in one patient, and another two patients had ICC- and TCA-positive PBPC samples despite tumor-negative PB and BM before priming. These results are similar to those previously reported for PBPC primed with cyclophosphamide and GM-CSF. CONCLUSION: In patients with advanced breast cancer responsive to cytotoxic chemotherapy, tumor-cell contamination is not increased in PBPC collected after 5 or 7 days priming with G-CSF and appears similar to that seen when PBPC are primed with cyclophosphamide followed by GM-CSF.

Synthetic glucocorticoids: antenatal administration and long-term implications.

A clear relationship between intrauterine development and later life predisposition to long-term disease is well established. Weight at birth provides a surrogate measure for fetal development and low birth weight predicts changes in most endocrine axes in adulthood. The exposure of the fetus to elevated levels of either endogenous or synthetic glucocorticoids, pre and periconceptional nutritional status and immediate postnatal development including catch-up growth all contribute substantially to the development of adult onset disease. Fetal exposure to high levels of glucocorticoids has direct clinical relevance. Synthetic glucocorticoids (betamethasone/ dexamethasone) are administered to women at risk of preterm delivery to advance fetal maturation and reduce neonatal morbidity and mortality. However, in human pregnancy, evidence suggests that fetal exposure to synthetic glucocorticoids has detrimental effects on birth outcome, childhood cognition and long-term behavior. Studies in animals have established a link between prenatal exposure to synthetic glucocorticoids and alterations in fetal development as well as changes in placental function. These developmental alterations appear to be permanent. Whether this is the case in humans awaits long-term follow-up of children enrolled in randomized controlled trials of prenatal glucocorticoid therapy. The research challenges in this field are now centered on uncovering the mechanisms by which glucocorticoids are involved in programming the fetus for its future life, and discovering ways in which the effectiveness and safety of antenatal glucocorticoids can be enhanced. The purpose of this mini-review is to provide a background into the use of antenatal synthetic corticosteroids and to highlight and summarize recently published clinical and animal-based studies.

Human herpesvirus 8 open reading frame 26 and open reading frame 65 sequences from multiple myeloma patients: a shared pattern not found in Kaposi's sarcoma or primary effusion lymphoma.

Human herpesvirus 8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus, has been implicated in the pathogenesis of Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), multicentric Castleman's disease, and recently multiple myeloma (MM). DNA sequence analyses of HHV-8 suggest that multiple HHV-8 strains exist. We extracted DNA from 24 patients with MM and 3 patients with monoclonal gammopathy of undetermined significance and compared HHV-8 open reading frames (ORFs) 26 and 65 sequences with those derived from patients with KS, PEL, and two HHV-8-positive PEL cell lines KS-1 and BC-1. ORF26 sequence data suggest that MM patients are consistently carriers of HHV-8 strain subtype C3. All MM patients also consistently revealed either a single bp deletion or substitution at position 112197 in ORF65. This unique alteration is not present in patients with KS or PEL or in PEL cell lines. It occurs in the portion of ORF65 that is known to be responsible for a serological response to HHV-8.

The effect of oxygen content during an initial sustained inflation on heart rate in asphyxiated near-term lambs.

OBJECTIVE: At birth, an initial sustained inflation (SI) uniformly aerates the lungs, increases arterial oxygenation and rapidly improves circulatory recovery in asphyxiated newborns. We hypothesised that lung aeration, in the absence of an increase in arterial oxygenation, can increase heart rate (HR) in asphyxiated near-term lambs. INTERVENTIONS: Lambs were delivered and instrumented at 139±2 days of gestation. Asphyxia was induced by umbilical cord clamping and then delaying the onset of ventilation until mean carotid arterial pressures (CAPs) had decreased <20 mm Hg. Lambs then received a single 30-s SI using nitrogen (N2; n=6), 5% oxygen (O2; n=6), 21% O2 (n=6) or 100% O2 (n=6) followed by ventilation in air for 30 min. MAIN OUTCOME MEASURES: HR, CAP and pulmonary blood flow (PBF) were continuously recorded. RESULTS: HR and PBF increased more quickly in lambs resuscitated with 100% and 21% O2 than with 5% O2 or N2. HR and PBF recovery in the 5% O2 group was delayed relative to all other oxygen SI groups. HR in 5%, 21% and 100% O2 groups reached 100 bpm before the SI was complete. HR and PBF in the N2 group did not increase until 10 s after the SI was completed and ventilation was initiated with air. CAP tended to increase quicker in all O2 groups than in N2 group. CONCLUSIONS: Oxygen content during an SI is important for circulatory recovery in asphyxiated lambs. This increase in HR is likely driven by the increase in PBF and venous return to the heart.

Expression of a developmental stage-specific antigen by neuronal precursor cells of human fetal cerebellum.

A monoclonal antibody that was prepared against human neuroblastoma cells was shown to react strongly with fetal brain and moderately with adult brain by quantitative absorption testing. Immunoperoxidase staining demonstrated expression of the antigen by neuronal precursor cells in the cerebellar external granular layer of a 24- to 26-week fetus but not by their mature derivatives in the granular and molecular layers of adult cerebellum. The antigen was also present on subventricular cells of fetal cerebral cortex, as well as adult and fetal astrocytes. The expression of this antigen by neuronal precursor cells in the external granular layer but not their mature derivatives suggests that it is a stage-specific marker for cerebellar neuronal development.

Clinical collection and use of peripheral blood stem cells in pediatric patients.

Peripheral blood stem cells have been used in lieu of marrow as autologous cellular support after marrow-ablative radio/chemotherapy. Autologous marrow support allows the use of higher, more effective doses of therapy. Peripheral blood stem cells (PBSC) offer the potential for this form of "transplant" in patients with marrow involved with disease. PBSC use also allows the avoidance of marrow harvest under general anesthesia. Previous reports of PBSC use have been limited to adults. This article describes peripheral blood stem cell collection in children, and documents the successful use of such cells in a 21/2-year-old boy and a 3-year-old girl with progressive stage IV neuroblastoma involving the marrow. Collections were performed using a Fenwal CS3000 blood cell processor primed with fresh frozen plasma and red cells, using a low flow rate to avoid citrate toxicity. The transplant was performed using collections that were negative or low in neuroblastoma cells (as detected by anti-neuron-specific enolase and antineuroblastoma monoclonal antibodies) after preparation with high-dose cyclophosphamide, etoposide, and cisplatin. Posttransplant recovery was uneventful, and engraftment was comparable to that in 4 patients treated with a similar preparative regimen followed by infusion of autologous marrow. Using careful technique, PBSC support in lieu of marrow may be a viable treatment modality in pediatric neuroblastoma or other solid tumors, particularly when the marrow is involved with disease.

The effect of prenatal betamethasone administration on postnatal ovine hypothalamic-pituitary-adrenal function.

Prenatal exposure to glucocorticoids is associated with alterations in fetal growth and endocrine function. However, few studies have examined the effects of clinically relevant doses of glucocorticoids on postnatal hypothalamic-pituitary-adrenal (HPA) function. To determine the effects of maternal or fetal betamethasone administration (0.5 mg/kg maternal or estimated fetal weight) on postnatal HPA function at 6 months and 1 year postnatal age, pregnant ewes were randomized into the following treatment groups: no treatment (n=6); maternal saline (n=6); single maternal betamethasone (M1) (n=6); repeated maternal betamethasone (M4) (n=6); fetal saline (n=5); single fetal betamethasone (n=6) and repeated fetal betamethasone (F4) (n=6). Single injections were given at 104 days of gestation and repeated injections at 104, 111, 118 and 125 days. Lambs were born spontaneously and the ACTH and cortisol responses to i.v. corticotropin-releasing hormone (CRH) (0.5 microg/kg) plus arginine vasopressin (AVP) (0.1 microg/kg) were measured at 6 months and 1 year postnatally. At 6 months postnatal age, neither maternal nor fetal prenatal betamethasone administration altered significantly the ACTH and cortisol responses to CRH+AVP. However, in animals at 1 year postnatal age, a previous single injection of betamethasone to the mother (M1) resulted in significantly elevated basal and stimulated cortisol levels (P<0.05), without significant change in the ACTH response. In contrast, betamethasone administration to the fetus resulted in significantly attenuated ACTH responses to CRH+AVP at 1 year compared with control animals (P<0.05), but these were not associated with any significant changes in basal or stimulated cortisol levels. All control animals exhibited a significant increase in peak ACTH responses to CRH+AVP between 6 months and 1 year postnatal age (P<0.05). After prenatal betamethasone (F4, M4) the difference in peak ACTH response between animals at 6 months and 1 year postnatal age was abolished. We conclude that in sheep between 6 months and 1 year postnatal age, HPA function undergoes developmental changes that are influenced by prenatal glucocorticoid exposure. Furthermore, the effects of glucocorticoid on postnatal HPA responses may vary according to the time in gestation that the steroid was administered, and whether it was given directly into the fetal or maternal compartment.

The fetal placental hypothalamic-pituitary-adrenal (HPA) axis, parturition and post natal health.

A general characteristic of fetal endocrine maturation across different species is the enhanced activity of the fetal hypothalamic-pituitary-adrenal (HPA) axis during late gestation. Precocious activation of this axis may occur when the fetus is exposed to an adverse intra-uterine environment, such as hypoxemia. HPA development is associated with increased levels of ACTH(1-39) and adrenal corticosteroids (cortisol in sheep and human) in the fetal circulation, and increased expression of mRNA encoding corticotrophin releasing hormone (CRH) in the hypothalamus, proopiomelanocortin (POMC) in the pituitary, and key steroidogenic enzymes in the fetal adrenal. At term, increased levels of cortisol act on the placenta/trophoblast derived cells to increase expression of prostaglandin synthase Type II (PGHS-II). In human gestation, cortisol also decreases expression of 15-hydroxyprostaglandin dehydrogenase (PGDH) in chorionic trophoblast cells. Increased synthesis and decreased metabolism of prostaglandin (PG) results, during late gestation, in enhanced output of primary PG, which in turn increases the activity of 11 beta-hydroxysteroid dehydrogenase (11 beta HSD) in the human fetal membranes. Increased chorionic 11 beta HSD-1 results in increased local generation of cortisol from cortisone, with further paracrine/autocrine stimulation of PG output. Increased fetal cortisol contributes to the maturation of organ systems required for postnatal extra-uterine survival. However, excessive levels of feto-placental glucocorticoid, derived from maternal administration of synthetic corticosteroids or sustained endogenous fetal cortisol production, results in intrauterine growth restriction. Fetal sheep, exposed to maternal betamethasone in late gestation, develop insulin resistance and exaggerated adrenal responses to HPA stimulation by 6-12 months postnatal life. Thus, the level of fetal HPA activity is crucial not only for determining gestation length, but may also predict pathophysiologic adjustments in later life.

Treatment of poor-risk neuroblastoma patients with high-dose chemotherapy and autologous peripheral stem cell rescue.

A single institutional pilot study was conducted in which 12 poor-risk neuroblastoma (NB) patients were uniformly treated with multi-agent induction chemotherapy followed by myeloablative consolidation chemotherapy and unpurged peripheral blood stem cell (PBSC) rescue. In addition to using standard criteria for evaluating response to induction chemotherapy, tumor cell contamination of the peripheral blood and/or bone marrow was analyzed in seven patients by immunocytology using a panel of five anti-NB monoclonal antibodies. Seven patients had morphologic evidence of bone marrow disease at the time of diagnosis, and two additional patients had tumor cells detected in bone marrow samples by immunocytology prior to the second cycle of chemotherapy. After three cycles of chemotherapy, two of the 12 patients continued to have evidence of bone marrow disease. Samples from 29 PBSC harvests collected from nine patients were also analyzed for the presence of contaminating tumor cells by immunocytology. In each case, the stem cells were found to be free of tumor. Eleven of the 12 patients underwent myeloablative therapy and PBSC rescue; five patients remain alive without disease progression, 28+ to 53+ months from diagnosis, and six patients have developed recurrent disease. We conclude that PBSCs can be successfully harvested from children with NB, and used for hematopoietic reconstitution following myeloablative chemotherapy. However, more effective therapy for poor-risk NB patients is still urgently needed.

Immunocytochemical detection of tumor cells in bone marrow and peripheral blood stem cell collections from patients with ovarian cancer.

High-dose chemotherapy (HDC) followed by autologous hematopoietic reconstitution is an experimental treatment option for patients with epithelial ovarian cancer. However, the incidence of occult ovarian tumor cell involvement in autologous bone marrow (BM) or peripheral blood stem cell (PBSC) autografts has not been widely investigated. We used a highly sensitive immunocytochemical (ICC) procedure that detects occult blood-borne tumor micrometastases. We analyzed 24 BM specimens (15 obtained during therapy and 9 harvest samples) and seven PBSC specimens from 22 patients with ovarian cancer. Overall, ICC analysis detected immunostained tumor cells in 10 of 23 evaluable BM specimens (43%) from 9 of 19 patients (47%). One of 9 (11%) harvest samples contained tumor cells. Only one of the 10 ICC-positive BM specimens had tumor cells detected by routine histopathological analysis. ICC-detectable tumor cells were cleared from the marrow of two patients during chemotherapy. None of the seven PBSC specimens contained tumor cells. We conclude that ovarian cancer micrometastases have the potential to contaminate BM, as is also the case in patients with other epithelial malignancies. In the limited number of specimens analyzed, PBSC harvests appeared to provide a less tumor-contaminated source of hematopoietic stem cells for autologous transplantation.

Frequent detection of tumor cells in hematopoietic grafts in neuroblastoma and Ewing's sarcoma.

Many poor-risk neuroblastomas and tumours of the Ewing's sarcoma family (ET) recur despite autologous transplants. Recurrence may be due to tumor cells contained in the BM harvests or PBSC harvests. The objectives of this prospective study were to: (1) determine the incidence and degree of tumor cell contamination in paired BM and PBSC harvests; and (2) determine the efficacy of tumor cell purging by immunomagnetic CD34+ cell selection. 198 samples from 11 consecutive patients with neuroblastoma or Ewing's sarcoma were analyzed. We assayed tumor contamination by RT-PCR assay for PGP 9.5, plus immunohistochemistry for neuroblastoma-specific antigens (the latter in neuroblastoma only). None of these patients had tumor cells detected in their BM by clinical histology immediately before BM or PBSC harvests. However, 82% of PBSC and 89% of backup BM harvests were contaminated with tumor by RT-PCR and/or immunocytochemistry assays. Unselected PBSC and BM harvests contained similar quantities of tumor cells (median, approximately 200000 cells). Cyclophosphamide plus G-CSF mobilization did not affect the incidence or level of contamination in PBSC harvests, as compared to blood obtained before mobilization. Immunomagnetic CD34+ cell selection depleted tumor cells by a median of 3.0 logs for PBSC, and 2.6 logs for BM harvests.

Ventilatory and arousal responses of sleeping lambs to respiratory challenges: effect of prenatal maternal anemia.

We have examined the effects of exposure to chronic maternal anemia, throughout the final one-third of gestation, on postnatal ventilatory and arousal responses to hypoxia, hypercapnia, and combined hypoxia-hypercapnia in sleeping lambs. While resting quietly awake, lambs from anemic ewes had higher arterial PCO(2) levels than control animals during the first 2-3 postnatal wk, but pH, arterial PO(2), and arterial O(2) saturation were not different. During active and quiet sleep lambs from anemic ewes had higher end-tidal CO(2) levels than control animals when breathing room air and at the time of spontaneous arousal or when aroused by progressive hypercapnia or by combined hypoxia-hypercapnia. Ventilation and arterial O(2) saturation during uninterrupted sleep and ventilatory responsiveness to hypoxia (inspiratory O(2) fraction, 10%), progressive hypercapnia, and combined hypoxia/hypercapnia were not significantly affected by exposure to maternal anemia. Our findings show that maternal anemia results in elevated PCO(2) levels in the offspring. This effect may be due, at least in part, to altered pulmonary function.

Development of ventilatory responsiveness to progressive hypoxia and hypercapnia in low-birth-weight lambs.

Our aim was to determine the effects of low birth weight on ventilatory responses to progressive hypoxia and hypercapnia during early postnatal life. Seven low-birth-weight (2.7 +/- 0.3 kg) and five normal-birth-weight (4.8 +/- 0.2 kg) lambs, all born at term, underwent weekly rebreathing tests during wakefulness while arterial PO2, PCO2, and pH were measured. Hypoxic ventilatory responsiveness (HOVR; percent increase in ventilation when arterial PO2 fell to 605 of resting values) increased in normal lambs from 86.6 +/- 7.1% at week 1 to 227.4 +/- 24.9% at week 6. In low-birth-weight lambs, HOVR was not significantly different at week 1 (60.1 +/- 18.7%) from that of normal lambs but did not increase with postnatal age (56.6 +/- 19.3% at week 6). HOVR of all lambs at 6 wk was significantly correlated with birth weight (r2 = 0.8). Hypercapnic ventilatory responsiveness (gradient of ventilation vs. arterial PCO2) did not change with age and was not significantly different between groups [84.7 +/- 7.5 (low-birth-weight lambs) vs. 89.4 +/- 6.6 ml.min-1.kg-1.mmHg-1 (normal lambs)]. We conclude that intrauterine conditions that impair fetal growth lead to the failure of HOVR to increase with age.

Gender and pre-atherosclerotic lesions. Effects on prevalence in human abdominal aortas.

Gross and microscopic examination of equivalent segments of abdominal aortas obtained at autopsy from 39 male patients aged 10 to 30 years (mean, 20.5 years) and 37 female patients aged 9 to 30 years (mean, 20.9 years) revealed no significant difference in the prevalence of aortic pre-atherosclerotic lesions in male v female patients. The prevalence of fatty streaks and early and late fibromusculoelastic lesions did not change significantly with increasing age, suggesting that in the abdominal aorta, the majority of precursor lesions for atherosclerosis are already present by 15 years of age. These findings suggest that the reduced severity of atherosclerosis in female patients is not due to the presence of smaller numbers (or extent) of precursor lesions, but rather to slower progression of these lesions in female patients.

Quality control of immunocytologic testing. Prolonged preservation of cell surface antigen reactivity with magnesium chloride-sucrose solution.

A sucrose-magnesium chloride-glycerol storage solution (sucrose-magnesium chloride) can preserve antigenicity of cytologic preparations for prolonged periods of time. This storage method was evaluated relative to our immunocytologic technology with the specific aim of exploring its use as a quality control measure. Neuroblastoma and leukemia cell lines, patient bone marrow, and blood specimens were serially tested during a 15-week period to evaluate preservation of immunoreactivity and cell morphological features. Slides that had been air dried and stored at 4 degrees C were compared with those that had been fixed with methanol and paraformaldehyde and stored in sucrose-magnesium chloride at -20 degrees C. The sucrose-magnesium chloride method proved to be superior, and antigen-antibody binding and cell morphology were preserved even after 15 weeks of storage. This method, now in use as a quality control measure in our laboratory, constitutes a practical assurance program for immunocytologic analysis.