Inhibition of enzymic digestion of amylose by free fatty acids in vitro contributes to resistant starch formation.

The effect of lipids on the enzymic breakdown of starch was investigated using an in vitro assay system. Mixtures of potato amylose, amylopectin and starch and various lipids were incubated at 37 degrees C for 10 min and subjected to digestion by alpha-amylase (EC 3.2.1.1) and amyloglucosidase (EC 3.2.1.33). Lauric, myristic, palmitic and oleic acids and lysolecithin inhibited enzymic hydrolysis of amylose by approximately 35% (P < 0.05). Stearic acid and cholesterol had no effect on the enzymic breakdown of amylose. Retrograded amylose was hydrolyzed less readily (P < 0.05) than solubilized amylose, but the breakdown was not further inhibited in the presence of lauric acid. Fatty acids had no effect on the enzymic hydrolysis of amylopectin, whereas inhibition by fatty acids of the breakdown of whole starch was consistent with only the amylose fraction being affected. The possibility that interactions between starch and fatty acids in the digestive tract could contribute to the formation of resistant starch is considered.

Diltiazem and pentoxifylline determination in postmortem specimens.

A 78-year-old woman was found dead in her basement. Qualitative screening of available postmortem specimens detected the presence of diltiazem and pentoxifylline. Quantitations were carried out by gas chromatography using nitrogen-phosphorus detection and confirmed by gas chromatography-mass spectrometry with the following results: blood, 0.59 mg/dL diltiazem and 0.63 mg/dL pentoxifylline; urine, 1.17 mg/dL diltiazem and 0.08 mg/dL pentoxifylline; bile, 0.40 mg/dL diltiazem and 0.22 mg/dL pentoxifylline; gastric contents, 0.28 mg/dL diltiazem and 0.02 mg/dL pentoxifylline. Both drugs were found qualitatively in formaline-fixed tissues.

S-nitrosohemoglobin in the fetal circulation may represent a cycle for blood pressure regulation.

It has recently been demonstrated, in rats, that hemoglobin transports nitric oxide (NO), as S-nitrosocysteine, from the lungs to the peripheral tissues. This cycle may be involved in the regulation of blood pressure and efficient delivery of oxygen in adult animals. We sought to determine whether this model was applicable to the human fetus. Umbilical cord blood was obtained from deliveries between 37 and 42 weeks of gestation (n = 19). NO, released from erythrocyte s-nitrosohemoglobin (SNO-Hb), was determined by the Saville reaction and total plasma NO was determined by the Greiss reaction. SNO-Hb levels were found to be higher in the umbilical vein, [SNO]/[Hb] = 2.19 +/- 1.22 (X10(-3)), than in the artery, [SNO]/[Hb] = 1.45 +/- 0.66 (X10(-3)) (P < 0.001, Wilcoxon Signed Rank test). This supports the hypothesis that fetal blood pressure may be regulated by erythrocytes acting via a hemoglobin-based mechanism.

Hypoxia stimulates ecNOS mRNA expression by differentiated human trophoblasts.

Cytotrophoblasts isolated from normal human placenta cultured under normoxic conditions (20% O2, pO2 = 130 mmHg) for 48-72 h differentiate to a form which expresses high levels of hCG and which morphologically resembles syncytiotrophoblast. We had previously shown that hypoxia (0-1% O2, pO2 = 12-14 mmHg) blocks this differentiation process, although trophoblasts exposed to hypoxia for up to 96 h were completely viable. In this article we showed that trophoblast responds to hypoxia by expressing the hypoxia-sensitive DNA binding protein HIF-1. We also showed that in trophoblast cultured under normoxic conditions, expression of endothelial cell nitric oxide synthase (ecNOS) mRNA increases with time, reaching a maximum in 48-72 h. However, in trophoblast maintained under hypoxic conditions for 48 h (after an initial 24 h in normoxia), expression of ecNOS mRNA is greatly reduced. These observations are consistent with the expression of ecNOS by syncytiotrophoblast but not by cytotrophoblast. In contrast, exposure of differentiated trophoblasts to hypoxia for 24 h (after 48-72 h in normoxia) significantly stimulates expression of ecNoS mRNA over that of cells maintained continuously in normoxia. These results suggest that in differentiated trophoblast hypoxia can stimulate ecNOS expression.

Juvenile rheumatoid arthritis: benefits from massage therapy.

Studied children with mild to moderate juvenile rheumatoid arthritis who were massaged by their parents 15 minutes a day for 30 days (and a control group engaged in relaxation therapy). The children's anxiety and stress hormone (cortisol) levels were immediately decreased by the massage, and over the 30-day period their pain decreased on self-reports, parent reports, and their physician's assessment of pain (both the incidence and severity) and pain-limiting activities.

Characterization by serial deletion competition ELISAs of HIV-1 V3 loop epitopes recognized by monoclonal antibodies.

Characterization of the sites recognized by antibody on the V3 loop of the envelope glycoprotein gp120 of HIV-1 was done by competition ELISAs on a series of four mouse mAbs, a human mAb and a human Fab. The solid-phase antigen consisted of biotin-YNKRK-RIHIGPGRAFYTTKN, a sequence from the center of the V3 loop of gp120MN, applied to streptavidin-coated wells. Competing antigens were two series of peptides with the HIV-1MN sequence each serially deleted at either the N or C terminus but kept constant at the other terminus. For each series, the amino acid at the deleting end needed to give a minimum KD was identified. The epitope was defined as the sequence including both of the identified amino acids as terminal amino acids. For the six antibodies reported, the epitope length ranged from seven to 14 amino acids. Use of a cyclic peptide as competing fluid-phase antigen suggested the influence of conformational constraints on presumed "linear" epitopes. The operationally-defined epitope was longer than the contact residues in one of two instances in which the X-ray crystallographic structure had been determined. The longer estimates of epitope length in the current study based on competition ELISAs with serial deletions suggest that non-contact residues are significant both in epitope definition and in functional applications including immunogen design.

Tachycardia as the sole fetal heart rate abnormality after funipuncture.

BACKGROUND: Fetal bradycardia is a common complication of funipuncture. We present a case of fetal exsanguination in which fetal tachycardia was the sole fetal heart rate abnormality. CASE: Funipuncture was performed at 32 weeks' gestation for evaluation of Rh isoimmunization. A persistent fetal tachycardia ensued and, although there was no immediate ultrasound evidence of bleeding, repeat ultrasonography revealed active bleeding at the puncture site. A neonate with an initial hematocrit of 42% was delivered by cesarean. Despite aggressive replacement of blood products, a repeat hematocrit was only 35% and a severe, persistent coagulopathy ensued. The newborn died 18 hours after delivery. Autopsy findings were consistent with neonatal coagulopathy. CONCLUSION: Although fetal bleeding is usually a common, relatively benign complication of funipuncture, streaming may not always be detected on ultrasonographic examination. Our case demonstrates that fetal tachycardia may be the only sign of fetal hemorrhage.

Predictors of survival in HIV-infected tuberculosis patients.

OBJECTIVE: To ascertain predictors of survival in HIV-infected tuberculosis (TB) patients. DESIGN: Retrospective cohort study. SETTING: New York City public hospital. PATIENTS: Fifty-four consecutive HIV-seropositive patients with newly diagnosed TB and no other AIDS-defining illnesses. MAIN OUTCOME MEASURES: CD4+ T-lymphocyte counts, completion of anti-TB therapy, repeat hospitalizations with TB, and survival. RESULTS: Forty-five (84%) of the 54 patients died a median of 15 months after TB diagnosis (range, 1-80 months), five (9%) were alive after a median of 81 months (range, 75-84 months), and four (7%) were lost to follow-up after a median of 42 months (range, 30-66 months). In univariate analyses, disseminated TB, intrathoracic adenopathy, oral candidiasis and CD4 count depletion were each associated with decreased survival. In a multivariate analysis, CD4 count depletion was the only independent predictor of decreased survival. Repeat hospitalization with TB occurred in 10 out of 15 patients who did not complete anti-TB therapy compared with one out of 21 patients who completed anti-TB therapy (P < 0.001). CONCLUSION: The clinical presentation of TB and CD4 count at TB diagnosis are each predictive of survival in HIV-seropositive TB patients. The CD4 count is the only independent predictor of survival.

The role of nitric oxide in the pathogenesis of preeclampsia.

OBJECTIVE: Nitric oxide, a potent vasodilator released by endothelial cells, inhibits platelet aggregation and adhesion to vascular endothelial surfaces. Because endothelial cell damage is considered pivotal in the pathogenesis of preeclampsia, this study was initiated to determine whether nitric oxide production is decreased in patients with preeclampsia. STUDY DESIGN: Twenty-six patients with preeclampsia (as defined by a blood pressure > or = 140 mm Hg systolic or 90 mm Hg diastolic plus proteinuria, > or = 300 mg per 24 hours or > or = 2+ by dipstick, both occurring on two occasions > or = 4 hours apart) and 26 normotensive women with singleton gestations in the third trimester were studied. Because nitric oxide is spontaneously oxidized to both nitrite and nitrate, two analytic assays were used serially. Serum nitrite levels were initially determined with the Greiss reagent and subsequently analyzed with Escherichia coli nitrate reductase. RESULTS: With the Greiss reagent alone the mean +/- SEM of serum nitrite level in 26 patients with preeclampsia was significantly decreased compared with 26 normotensive patients (3.46 +/- 1.43 mumol/L vs 4.65 +/- 0.85 mumol/L, p = 0.02). With the addition of the nitrate reductase enzyme of Escherichia coli the mean +/- SEM of serum nitrite level in 26 preeclamptic patients was again significantly decreased compared with 26 normotensive patients (20.04 +/- 1.25 mumol/L vs 27.38 +/- 2.23 mumol/L, p = 0.02). One patient with the syndrome of hemolysis, elevated liver enzymes, and low platelets demonstrated a concurrent decrease in serum nitrite over a 2-week period, emphasizing the relationship of nitric oxide to the pathophysiologic features of the syndrome. CONCLUSIONS: Circulating levels of nitrite are decreased in patients with preeclampsia. These data support the concept that diminished nitric oxide synthesis contributes to the pathophysiologic changes seen in preeclampsia.

Serial deletion mapping by competition ELISA assay: characterization of a linear epitope in the V3 loop of HIV-1.

Precise epitope mapping and characterization is important for development of a subunit vaccine. To identify epitopes in the principal neutralizing determinant (PND) within the V3 loop of human immunodeficiency virus type 1 (HIV-1), sera were screened in a direct ELISA assay with a coating peptide consisting of IHIGPGRAF, a specific sequence commonly found in the loop, linked at the C terminus to GAGAAK, a nonspecific hexapeptide. Epitope mapping experiments revealed that a competition ELISA assay using IGPGRAFGAGAAK as coating peptide was superior to a direct ELISA assay for epitope definition and characterization. The competing peptides contained only specific sequences and were serially deleted of single amino acids first at the N terminus and then at the C terminus. Study of the most highly reactive serum identified in the initial screening identified the epitope (the shortest peptide with the most potent inhibitory activity) as IGPGRAF. Deletion of a single amino acid from the C terminus of the epitope resulted in complete loss of activity as competing peptide. In contrast, single amino acid deletions of three N-terminal amino acids resulted in a stepwise 2700-fold reduction in affinity. RAF was the shortest peptide with inhibitory activity. Additional studies are needed, especially with regard to choice of coating peptide, to establish the general utility of the described epitope mapping procedure. However, the above method, termed serial deletion mapping, may be useful for defining and characterizing linear epitopes and thus may be particularly informative in investigating the multiple overlapping epitopes of the PND.

Applying psychoanalysis in an unconventional context. Adapting infant-parent psychotherapy to a changing population.

The model of psychoanalytically oriented infant-parent psychotherapy originally proposed by Selma Fraiberg and her colleagues has evolved in the nearly two decades since its inception. This paper provides an overview of current developments in the model's core intervention techniques, with special reference to modifications that have emerged in response to recent efforts to intervene with an exceptionally psychosocially disadvantaged population. A conceptual framework for the intervention is offered, emphasizing the special therapeutic opportunities offered during the couple's transition to parenthood. Finally, the concept of "bureaucratic transference" will be briefly elaborated as it has emerged in efforts to apply psychoanalysis in work with social agencies on behalf of infants and their families.

Influence of solid-phase antigen in competition enzyme-linked immunosorbent assays (ELISAs) on calculated antigen-antibody dissociation constants.

The competition ELISA method described in 1985 by Friguet and colleagues has frequently been used to determine dissociation constants (KD) of antigen-antibody reactions. Subsequently Stevens suggested a correction for the bivalency of IgG. In either case, the KD is assumed to vary only with the composition of competing fluid-phase antigen and consequently should not be affected by the solid-phase antigen. However, during the course of experiments defining epitopes to the V3 loop of human immunodeficiency virus type 1, both the composition and density of solid-phase antigen were capable of significantly influencing the calculated values. With one solid-phase antigen, the calculated KD was a function of antigen density. With a second solid-phase antigen, the calculated KD did not vary with the density. With the latter antigen or with low densities of the former, KDs calculated using the Stevens correction for bivalency were close to the estimate obtained by a radiolabeled peptide precipitation assay. Accordingly, since the density and composition of solid-phase antigen may alter the KD calculated from competition ELISAs, such estimates should be confirmed by a more readily interpretable immunological method.

The dynamic functions of the act of reading.

This study of 68 avid fiction readers demonstrated that for those who love fiction, deeply personal meanings pervade the act of becoming absorbed in a work and shape the ways that they can use fiction in their lives as a whole. Each respondent had a unique, largely unconscious relationship to the act of reading, a relationship that expressed themes and addressed functions related to self-organisation, real and fantasized relatedness, affect regulation, and the repetition or working through of conflict. To the extent that these inner determinants of the reading experience became rigid and unyielding, readers derived less newness, richness, and depth, though not necessarily less benefit, from engagement in fiction. Greater flexibility allowed reading to take place in what Winnicott called potential space. It enabled readers to involve themselves in fiction without sacrificing either the work's uniqueness or their own inner life, so permitting them to create new experience.