Rapid detection of contaminant bacteria in platelet concentrate using differential impedance.

BACKGROUND AND OBJECTIVES: Current FDA-approved culture-based methods for the bacterial testing of platelet concentrate (PC) can yield false-negative results attributed to Poisson-limited sampling errors incurred near the time of collection that result in undetectable bacterial concentrations. Testing PC at the point of issue (POI) extends the incubation period for any contaminant bacteria increasing the probability of detection. Data are presented from time-course experiments designed to simulate POI testing of bacterially contaminated PCs at different stages of growth using differential impedance sensing. STUDY DESIGN AND METHODS: Whole-blood-derived PCs were typically spiked with low numbers of bacteria (approximately 100 CFU/ml) and incubated under standard PC storage conditions. Each infected unit was evaluated every two hours over a 12-h period. All samples were treated with a chemical compound that induces stress in the bacterial cells only. The development of any bacterial stress was monitored by detecting changes in the dielectric properties of the PC using differential impedance. RESULTS: Differential impedance measurements and corresponding cell counts at the different time-points are presented for six organisms implicated in post-transfusion-septic reactions. All infected PCs were detected once contaminant bacteria reached concentrations ranging between 0·6 × 10(3) and 6 × 10(3)  CFU/ml irrespective of the phase of growth. Results were obtained within 30 min after the start of the assay and without the need for cell lysis or centrifugation. CONCLUSION: Differential impedance sensing can detect bacterial contamination in PC rapidly at concentrations below clinical thresholds known to cause adverse effects.

Hemoglobin Gun Hill: deletion of five amino acid residues and impaired heme-globin binding.

Hemoglobin Gun Hill, a new variant of adult hemoglobin, was found in a Caucasian and one of his three daughters. The abnormal hemoglobin had only half of the expected number of heme groups. Five amino acid residues appeared to be missing from the beta-globin chains. These residues occur in linear sequence in normal beta-chains in a region involved in heme-globin binding. A deletion of five amino acids in the beta-chains of hemoglobin Gun Hill is postulated. The most likely mechanism for the origin of such a hemoglobin variant would appear to be unequal crossing-over during meiosis.

The chemical composition of Martian soil and rocks returned by the mobile alpha proton X-ray spectrometer: preliminary results from the X-ray mode.

The alpha proton x-ray spectrometer (APXS) on board the rover of the Mars Pathfinder mission measured the chemical composition of six soils and five rocks at the Ares Vallis landing site. The soil analyses show similarity to those determined by the Viking missions. The analyzed rocks were partially covered by dust but otherwise compositionally similar to each other. They are unexpectedly high in silica and potassium, but low in magnesium compared to martian soils and martian meteorites. The analyzed rocks are similar in composition to terrestrial andesites and close to the mean composition of Earth's crust. Addition of a mafic component and reaction products of volcanic gases to the local rock material is necessary to explain the soil composition.

Major and trace elements and cosmic-ray produced radioisotopes in lunar samples.

Analytical data for 42 major and trace elements were mostly obtained by a combination of instrumental and radiochemical neutron activation analyses using both thermal and 14-million-electronvolt neutrons. Excesses of nitrogen and chlorine in the fines, compared with the rocks, are attributed to the solar wind. A striking similarity for contents of seven elements in lunar metal and metal from the calcium-rich achondrite Juvinas was noted. Fractional dissolution was used to separate five radionuclides produced by cosmic-ray bombardment in the fines and rock 57-40. Results for argon-39 from the reaction potassium-39 (n,p), and for argon-37, from the reaction calcium-40 (n,a), seem to require a neutron spectrum conitaining more neutrons below 2 million electronvolts than the evaporation spectrum or that given by Arnold, Honda, and Lal (1) or a strong time dependence for the neutron flux.

Dopamine-beta-hydroxylase activity and homovanillic acid in spinal fluid of schizophrenics with brain atrophy.

Schizophrenic patients with high ventricle brain ratios and cortical brain atrophy, as shown by computerized tomography, had decreased spinal fluid concentrations of homovanillic acid and dopamine-beta-hydroxylase activity. These decreased cerebral spinal fluid concentrations in patients with brain atrophy support the proposal of disturbed noradrenaline and dopamine neurotransmission in a subgroup of schizophrenic patients.

Overview of the Mars Pathfinder mission and assessment of landing site predictions.

Chemical analyses returned by Mars Pathfinder indicate that some rocks may be high in silica, implying differentiated parent materials. Rounded pebbles and cobbles and a possible conglomerate suggest fluvial processes that imply liquid water in equilibrium with the atmosphere and thus a warmer and wetter past. The moment of inertia indicates a central metallic core of 1300 to 2000 kilometers in radius. Composite airborne dust particles appear magnetized by freeze-dried maghemite stain or cement that may have been leached from crustal materials by an active hydrologic cycle. Remote-sensing data at a scale of generally greater than approximately 1 kilometer and an Earth analog correctly predicted a rocky plain safe for landing and roving with a variety of rocks deposited by catastrophic floods that are relatively dust-free.

Hemoglobin stability: observations on the denaturation of normal and abnormal hemoglobins by oxidant dyes, heat, and alkali.

Several unstable mutant hemoglobins have alterations which affect areas of the molecule involved in the attachment of heme to globin. Loss of heme from globin has been demonstrated during the denaturation of some of these unstable mutants. The importance of heme ligands for the stability of hemoglobin was illustrated in the present experiments on the denaturation of several hemoglobins and hemoglobin derivatives by heat, oxidative dyes, and alkali. Heating of normal hemolysates diluted to 4 g of hemoglobin per 100 ml at 50 degrees C for 20 hr in 0.05 M sodium phosphate, pH 7.4, caused precipitation of 23-54% of the hemoglobin. Dialysis against water or dilution of the sample decreased denaturation to 12-20%. Precipitation was decreased to less than 3.5% by the presence of 0.015 M potassium cyanide. Increasing the ionic strength of the medium increased precipitation. Cyanide prevented the formation of inclusion bodies when red cells containing unstable hemoglobin Philly, beta35 tyr --> phe, were incubated with the redox dye new methylene blue. Conversion to methemoglobin increased the rate of alkali denaturation of hemoglobin but the presence of potassium cyanide returned the denaturation rate to that of ferrohemoglobin. The ability of cyanide to decrease heat precipitation of hemoglobin may depend on a dimeric or tetrameric state of the hemoglobin molecule. Purified beta-chains, which exist as tetramers, were stabilized but purified monomeric alpha-chains were not rendered more heat resistant by the ligand. Stabilization of hemoglobin by cyanide required binding of the ligand to only one heme of an alphabeta-dimer. Hemoglobin Gun Hill, an unstable molecule with heme groups present only on the alpha-chains was quite heat stable in the presence of cyanide. The binding of cyanide to the iron atom in methemoglobin is thought to be associated with increased planarity of the heme group and increased stability of the heme-globin complex. The stabilizing effect of cyanide in the above experiments suggests that Heinz body formation, heat precipitation of hemoglobin, and the increased alkali denaturation of methemoglobin depend on changes of heme-globin binding.

Synthesis of hemoglobin Gun Hill: increased synthesis of the heme-free beta-GH globin chain and subunit exchange with a free alpha-chain pool.

Hemoglobin Gun Hill is an unstable mutant hemoglobin associated with mild compensated hemolysis. This abnormal protein has a deletion of five amino acids in the beta-chains. The deletion includes the heme-binding proximal histidine at position 92. The beta-chains of hemoglobin Gun Hill lack heme groups. Approximately 32% of the circulating hemoglobin in heterozygous subjects consists of the mutant hemoglobin. When reticulocytes were incubated with radioactive amino acid the specific activity of hemoglobin Gun Hill was three to six times that of hemoglobin A. Total incorporation of radioactivity into hemoglobin Gun Hill was two to three times that into hemoglobin A. There were 20-50% more total counts in beta-Gun Hill (beta(GH)) than in beta(A). These results indicate that in reticulocytes there was greater synthesis of the abnormal beta-chains than beta(A)-chains. The ratio of the specific activities of the alpha-chains of hemoglobin Gun Hill to the alpha-chains of hemoglobin A was 20: 1. There was evidence of a free pool of alpha-chains in the reticulocytes containing hemoglobin Gun Hill. After 10 min of incubation approximately 40% of the total alpha-chain radioactivity was in the free pool. When protein synthesis was blocked by incubation of reticulocytes with puromycin, the specific activity of the alpha-chains of hemoglobin Gun Hill continued to increase due to direct exchange of alpha-subunits between the free pool and preformed hemoglobin Gun Hill. Studies of the assembly of beta(A) and beta(GH) revealed that the rates of translation of the two polypeptide chains were equal and uniform. No evidence was obtained for the existence of "slow points" in the process of globin chain assembly. The studies also suggest that lack of strong heme-globin binding does not hinder the synthesis of globin chains.

Translation of -globin m-RNA in -thalassemia and the S and C hemoglobinopathies.

Genetic and biochemical evidence indicates that in beta-thalassemia there is impaired synthesis of the beta-globin chains of hemoglobin A. In patients heterozygous for the hemoglobinopathies, hemoglobin S and hemoglobin C, the mutant beta-chain is produced in smaller amounts than normal beta(A). Defective m-RNA translation has been suggested as a possible cause of decreased beta-globin polypeptide synthesis in thalassemia and the hemoglobinopathies. In the present study, the ribosomal assembly of beta-globin chains was examined in the peripheral, nucleated red blood cells and reticulocytes of patients with Cooley's anemia, thalassemia intermedia, sickle thalassemia, sickle cell anemia, hemoglobin C disease, and in hemolytic anemias not associated with a hemoglobinopathy. The translation times of beta(A), beta(S), and beta(C) did not differ significantly (average times; beta(A) = 75 sec, range 43-114, beta(S) = 69 sec, beta(C) = 92 sec). In thalassemia, no evidence was found for a delay in translation as the cause of the marked impairment of beta-globin synthesis. In several specimens of peripheral blood from thalassemic patients, the translation time of the beta-chain was even shorter than in nonthalassemic specimens (average time = 45 sec, range 35-59). The results suggest that the defect in beta-globin synthesis in beta-thalassemia is due to impaired initiation of beta-globin chain assembly or a quantitative deficiency in m-RNA.

Imbalance in alpha and beta globin synthesis associated with a hemoglobinopathy.

In contrast to findings in the thalasemia syndromes, studies of globin synthesis in subjects with structurally abnormal hemoglobins have generally revealed equal production of alpha and beta polypeptide chains. However, in the present investigation of globin biosynthesis in vitro in blood and marrow from two subjects heterozygous for unstable hemoglobin Leiden, beta6 or 7 Glu --> O, a significant excess of alpha-chain production was revealed. A mother and daughter of northern European ancestry with mild compensated hemolytic anemia were found to have 25% hemoglobin Leiden. Increased hemolysis occurred after the ingestion of a sulfonamide and during infections. Normal levels of hemoglobin A2, 3.0 and 2.7%, and hemoglobin F, 0.8 and 0.6%, were found in the two subjects. Similar percentages of the minor hemoglobins were demonstrated in other family members without hemoglobin Leiden. After incubation of peripheral blood with [(3)H]-leucine, the beta(A)/beta(Leiden) synthesis ratio was 1.3, and the specific activity of beta(Leiden) was 1.3-2 times beta(A). These results indicate preferential destruction of the unstable hemoglobin Leiden. However, in contrast to previous studies of other unstable hemoglobins, there was excess synthesis of alpha-chains. The total beta/alpha synthesis ratio was 0.47-0.63 in peripheral blood and 0.82 in marrow. A pool of free alpha-chains was demonstrated by starch gel electrophoresis and DEAE column chromatography. The synthesis of globin chains was balanced in family members without hemoglobin Leiden. This degree of predominance of alpha-chain synthesis in subjects with hemoglobin Leiden resembles the findings in heterozygous beta-thalassemia. However, the relatively normal hemoglobin content of the cells with this abnormal hemoglobin suggests the possibility of an absolute excess alpha-chain production in the hemoglobin Leiden syndrome.

Hemoglobin Philly (beta 35 tyrosine phenylalanine): studies in the molecular pathology of hemoglobin.

An abnormal unstable hemoglobin, hemoglobin Philly, was found in three members of a family, each of whom had evidence of a chronic hemolytic state. The presence of the mutant protein was suggested by the rapid appearance of inclusion bodies upon incubation of erythrocytes with brilliant cresyl blue and by the increased heat precipitability of the hemoglobin. However, no abnormal hemoglobin could be demonstrated by electrophoresis or column chromatography. Sulfhydryl titration of the hemolysates with p-mercuribenzoate indicated that there was an average of four reactive sulfhydryl groups per hemoglobin molecule instead of the usual two. The total number of hemoglobin sulfhydryl groups was normal; six groups were measured when denatured globin was reacted with 5,5'-dithiobis[2-nitrobenzoic acid]. This indicated that the increased sulfhydryl reactivity was due to an increased availability to p-mercuribenzoate of the usually unreactive hemoglobin cysteines at beta112 and alpha104. After treatment for (1/2) hr with 4-5 moles of p-mercuribenzoate per mole of hemoglobin, electrophoresis revealed that 30-35% of the hemoglobin had been dissociated into alpha- and beta-chains. Normal hemolysates revealed negligible splitting after 72 hr of similar treatment. The alpha- and beta-chains of hemoglobin Philly were separated from the unsplit hemoglobin A by carboxymethyl cellulose chromatography. Fingerprint and amino acid analyses revealed that tyrosine beta35 was replaced by phenylalanine. In hemoglobin Philly there is loss of the normal hydrogen bond between the tyrosine hydroxyl group and the carboxyl group of aspartic acid alpha126 at the alpha(1)beta(1) contact. This shifts the equilibrium from hemoglobin tetramers toward monomers, exposing the beta112 and alpha104 cysteines. In the cell, precipitation of the unstable monomers may contribute to erythrocyte destruction.

Hemoglobin Mississippi (beta 44ser----cys). Studies of the thalassemic phenotype in a mixed heterozygote with beta +-thalassemia.

Hemoglobin Mississippi (HbMS: beta 44ser----cys) has anomalous properties that include disulfide linkages with normal beta-, delta-, gamma-, and alpha-chains, and the formation of high molecular weight multimers. While heterozygotes for HbMS are clinically and hematologically normal and carriers of the beta +-thalassemia gene in our family had mild microcytic anemia, the proband with HbMS-beta +-thalassemia had a hemoglobin level of 7 g/dl, mean corpuscular volume (MCV) of 68 fl, reticulocytes of 2-6%, HbF of 18%, marked anisocytosis and poikilocytosis, and splenomegaly, all features of thalassemia intermedia. With oxidant stress, her erythrocytes developed multiple dispersed Heinz bodies, but HbMS was only mildly unstable. HbMS was susceptible to proteolytic degradation in the presence of ATP. The unexpectedly severe clinical findings in HbMS-beta +-thalassemia may result from the proteolytic digestion of HbMS, as well as the excessive alpha-chains characteristic of beta +-thalassemia, which combined provide the increment of cellular damage that results in the phenotype of thalassemia intermedia.

Some aspects of the pathophysiology of homozygous Hb CC erythrocytes.

We have studied erythrocytes from homozygous CC patients in vitro and in perfused rat mesoappendix vasculature to answer some long-standing questions. By examination of wet whole blood preparations, and by comparing the cell distribution on isopycnic continuous density gradients of whole blood samples from a splenectomized CC patient with those from three intact CC patients, we have demonstrated the presence of a distinct crystal-containing band of cells that is present in the former, but totally absent from the latter. We conclude that Hb CC cells containing crystals circulate in Hb CC individuals, but in intact patients they are effectively removed by the spleen. By use of 31P nuclear magnetic resonance and viscosity measurements on cells, we have demonstrated that intracellular aggregation of hemoglobin C occurs on deoxygenation even when no crystal formation is detectable by morphological methods. These two observations are in apparent contradiction with the absence of clinical microcirculatory impairment found in both intact and splenectomized CC patients. The contradiction was resolved by rheological studies on isolated rat mesoappendix preparations and erythrocyte diameter measurements that lead to the conclusion that the hemorheological properties of CC cells in the microcirculation are nearly normal because their increased viscosity is offset by their smaller diameter and size.

Genetic strategies in biological psychiatry.

Studies of the etiology of schizophrenia and other psychiatric illnesses may be executed by using a genetic framework in the experimental design. This article describes research strategies for identifying the genetic factors that produce a vulnerability to a psychiatric illness. The proposed strategies evaluate the role of a given genetic factor by comparing the transmission of this factor within pedigrees to the transmission of that illness. In a biologically heterogeneous disorder, these strategies can be used to identify homogeneous subgroups. This report also describes a strategy for identification of the environmental events that promote the development of a psychiatric illness, either independently or in conjunction with the genetic diathesis.

Biologic heterogeneity and psychiatrict research. Platelet MAO activity as a case study.

This article examines current research strategies in biological psychiatry and the possible effects of biological heterogeneity on these strategies. First, the limited power of t test comparisons of measurements obtained from groups of patients and controls is demonstrated through a computer simulation. Second, we examine statistically the data from 14 recent platelet MAO studies to see if the heterogeneity in results of these studies could relate to an underlying biological heterogeneity. Finally, we suggest research methods we believe may be more useful than the current standard paradigm for elucidating the biological etiologies of psychiatric syndromes.

Offspring of schizophrenics. III. Hyperactivity and neurological soft signs.

Twenty-nine male offspring of "continuous schizophrenics" (chronic, borderline, and chronic schizoaffective schizophrenics), plus controls, were given neurological and psychological examinations at age 7. Eight of the 29 were found to have high ratings on a factor score that was termed "hyperactive" (increased activity, impulsivity, distractibility, and emotional lability), and three of these boys had high ratings for neurological signs as well. These frequencies were significantly greater than the control values. Mild incoordination, such as awkwardness in performing rapidly alternating movements, was the neurological soft sign most elevated in the index group. Fifteen female offspring of schizophrenics were not found to differ from their controls on these measures. Previous studies of the childhood of male schizophrenics have found behavior patterns similar to the behavior of the boys who scored high on our hyperactive factors. It is thus likely that the "hyperactive cases" in this sample are even more at risk for developing schizophrenia in later life than the other offspring of schizophrenic parents.

The offspring of schizophrenics. II. Perinatal factors and IQ.

Within a sample of 60 children of schizophrenic parents, IQ and the correlates of IQ were examined. The Wechsler Intelligence Scale for Children was administered at age 7. The offspring of parents with schizophrenia were found to have a slightly lower IQ than their matched controls. This deficit could be attributed entirely to the male offspring. Using a second comparison group numbering several thousand, we computed correlations for various perinatal and socioeconomic factors with seven-year IQ. These correlations were also computed for the children of schizophrenics, and the difference in correlations was examined. IQs for the offspring of "continuous schizophrenics" (chronic, borderline, and chronic schizo-affective schizophrenics) were found to have lower correlations with socioeconomic indices and higher correlations, in a negative direction, with certain perinatal events. The findings were found to a lesser, nonsignificant degree among the small sample of offspring of acute schizophrenics. If these perinatal events are more negatively correlated with IQ because the children of continuous schizophrenics are specifically susceptible to them, it is possible that these factors are also influential in the later development of schizophrenia.

The offspring of schizophrenics. Fetal and neonatal deaths.

This is the first report in a projected series on neurological development among the offspring of schizophernics. An increased incidence of fetal and neonatal deaths is noted among offspring of schizophrenics when compared to a closely matched control group, using data collected prospectively. In many cases, no apparent reason for death was determined; in some cases, major neurological malformations were found. It is necessary to consider three possible explantions for these findings--genotype of the child, adverse intrauterine environment, and medication toxicity.

Computed tomographic scans in patients with schizophrenia, schizoaffective, and bipolar affective disorder.

Computed tomographic (CT) scans of 28 chronic schizophrenic patients, 15 chronic schizoaffective patients, and 19 patients with bipolar affective disorder were compared on three measures: ventricular size, sulcal prominence (cortical atrophy), and cerebellar atrophy. Because the patients with bipolar disorder were older, measures were adjusted by controlling for age statistically or excluding patients over age 50 years. After age correction, there were no significant differences across diagnostic groups. Each group contained some subjects with enlarged ventricles, sulcal prominence, and/or cerebellar atrophy. The similarity of CT scan results across the three groups argues against ascribing these abnormalities to any one psychiatric disorder or to a specific drug effect. Sampling effects and the possibility of differential causes of the findings in the different diagnostic groups must be considered. Examination of the correlations of these three CT scan measures found them to be significantly related to each other. Age correlated with all measures when patients over age 50 years were included in the analysis, but not for patients aged 50 years and younger.

Extreme MMPI scores and the Research Diagnostic Criteria. Screening college men for psychopathology.

This study compares psychiatric evaluations made with the Minnesota Multiphasic Personality inventory (MMPI) to evaluations with a standard clinical interview and the Research Diagnostic Criteria (RDC). The purpose was to generate a nonhospitalized, previously undiagnosed sample of persons who had psychiatric difficulties or symptoms. Of 385 college male volunteers, 56 with scores at least 3 SD above the mean on at least one MMPI scale were chosen as an index group, and 27, with all MMPI scores within normal limits, as a control group. In the index group, 82% met the RDC for at least one diagnosis, whereas only 22% of the control sample met the RDC for any diagnosis. One index subject met the RDC for schizophrenia; 15 met the RDC for a major affective disorder. Some correspondence between specific MMPI profile code types and RDC diagnoses was evident. Thus, researchers can identify a range of psychopathology meeting the RDC by using MMPI screening in a nonhospital setting. Such a research sample, free from the possible artifacts of hospitalization, drug treatment, and diagnostic labeling, can be useful particularly in testing hypotheses concerning the biological correlates of psychopathology.