Quantitation of red cell-bound IgG, IgA, and IgM in patients with autoimmune hemolytic anemia and blood donors by enzyme-linked immunosorbent assay

This paper describes an enzyme immunoassay for the quantitative determination of IgG, IgA, and IgM immunoglobulins on RBCs. Ether eluates made from RBCs were followed by an enzyme-linked immunosorbent assay of immunoglobulin concentration. Calibration curves were derived from immunoglobulin standards and the number of molecules of each isotype per RBC was calculated. The assay was carried out in 200 healthy blood donors and 62 patients with warm autoimmune hemolytic anemia (AIHA), two of them with a negative DAT. For healthy blood donors, mean values were 58 IgG, 16 IgA, and 3 IgM molecules per RBC. For patients with a positive DAT, the mean values were 3435 IgG, 157 IgA, and 69 IgM molecules per RBC. An increased level of IgA was found in 12 patients without IgA autoantibodies demonstrable in RBC eluates. Increased IgG levels were also observed in patients with a negative DAT and, in one case, an increased level of IgA was also found. The enzyme-linked immunosorbent assay using ether eluates is a sensitive method for quantitating RBC autoantibodies in patients with AIHA as well as immunoglobulins bound to RBCs in healthy individuals.

Calopogonium golden mosaic virus Identified in Phaseolus vulgaris from Western and Northern Regions of Costa Rica

Bean golden yellow mosaic virus (BGYMV, GenBank Accession No. M91604) is reported to be the main bean-infecting (Phaseolus vulgaris) begomovirus in Central America (1,2). Another begomovirus, Bean calico mosaic virus (BCaMV, GenBank Accession No. AF110189), is known to infect P. vulgaris in central Mexico. Bean samples with the viral symptom of foliar chlorosis were collected in different regions of Costa Rica from 1994 to 2001. Total nucleic acids were extracted and tested using polymerase chain reaction (PCR) with degenerate primer pair PBL1v2039/PCRc2 for DNA-B, which can give a different fragment size for some begomoviruses (4). PCR fragments were obtained from 119 bean samples. Fifty samples from the central valley produced 600-bp PCR fragments, which is typical for BGYMV (4), and one sample produced two fragments (500 and 600 bp). One sample from western Costa Rica had a 550-bp fragment, and 69 samples from the western and northern regions produced 500-bp fragments. One of the latter samples (No. 01-1152) was selected for PCR with degenerate primer pairs PAL1v1978/PAR1c715 for DNA-A and PBL1v2039/PBR1v800 for DNA-B (4). The amplified PCR fragments were 1.35 and 1.4 kb for DNA-A and DNA-B, respectively. These are expected sizes for a Western Hemisphere begomovirus. The DNA-A fragment was cloned and sequenced (GenBank Accession No. AF439402). Sequence comparisons indicated that this uncharacterized begomovirus (No. 01-1152) had 98, 97, and 93% nucleotide identities with the rep gene, common region, and coat protein gene promoter of Calopogonium golden mosaic virus (CalGMV, GenBank Accession Nos. AF439748 and AF439749, respectively) (3). CalGMV had been isolated from a weed, Calopogonium sp., collected in 1991 near Quepos in the west and Tilaran in the north of Costa Rica (3). Phylogenetic analysis of the viral sequence of the begomovirus associated with No. 01-1152 placed it in the Squash leaf curl virus clade (1). BCaMV is also in this phylogenetic clade, but sequence comparisons between CalGMV and BCaMV had <90% nucleotide identity, and so are distinct species. CalGMV is the begomovirus associated with No. 01-1152, and this is an example of the movement of a weed-infecting begomovirus into an agricultural crop. Since this Calopogonium sp. is widespread in Central America, it is important to determine if CalGMV is present in beans in other regions. The data also indicate that BGYMV and CalGMV infect beans in two geographically distinct regions of Costa Rica. References: (1) J. C. Faria et al. Phytopathology 84:321, 1994. (2) W. McLaughlin et al. Plant Dis. 78:1220, 1994. (3) M. R. Rojas et al. Annu. Rep. Bean Improv. Coop. 35:150, 1992. (4) M. R. Rojas et al. Plant Dis. 77:340, 1993.

Okadaic acid-sensitive activation of Maxi Cl(-) channels by triphenylethylene antioestrogens in C1300 mouse neuroblastoma cells

1. The regulation of Maxi Cl(-) channels by 17beta-oestradiol and non-steroidal triphenylethylene antioestrogens represents a rapid, non-classical effect of these compounds. In the present study we have investigated the signalling pathways used for the regulation of Maxi Cl(-) channel activity by oestrogens and antioestrogens in C1300 neuroblastoma cells. 2. Whole-cell Maxi Cl(-) currents were readily and reversibly activated by tamoxifen, toremifene and the membrane-impermeant ethyl-bromide tamoxifen, only when applied to the extracellular medium. 3. Pre-treatment of C1300 cells with oestrogen or cAMP prevented the antioestrogen-induced activation of Maxi Cl(-) channels. The inhibitory effect of 17beta-oestradiol and cAMP was abolished by the kinase inhibitor staurosporine. 4. Current activation was unaffected by the removal of intracellular Ca(2+) and Mg(2+), but was completely abolished in the presence of okadaic acid. These results are consistent with the participation of an okadaic acid-sensitive serine/threonine protein phosphatase in the activation of Maxi Cl(-) channels. However, neither oestrogen or antioestrogen treatment modified the total activity of the two major serine/threonine phosphatases, PP1 and PP2A, in C1300 cells. 5. Although the role of these Maxi Cl(-) channels remains unknown, our findings suggest strongly that their modulation by oestrogens and antioestrogens is linked to intracellular signalling pathways.

Consecutive light microscopy, scanning-transmission electron microscopy and transmission electron microscopy of traumatic human brain oedema and ischaemic brain damage

Cortical biopsies of 11 patients with traumatic brain oedema were consecutively studied by light microscopy (LM) using thick plastic sections, scanning-transmission electron microscopy ((S)TEM) using semithin plastic sections and transmission electron microscopy (TEM) using ultrathin sections. Samples were glutaraldehyde-osmium fixed and embedded in Araldite or Epon. Thick sections were stained with toluidine-blue for light microscopy. Semithin sections were examined unstained and uncoated for (S)TEM. Ultrathin sections were stained with uranyl and lead. Perivascular haemorrhages and perivascular extravasation of proteinaceous oedema fluid were observed in both moderate and severe oedema. Ischaemic pyramidal and non-pyramidal nerve cells appeared shrunken, electron dense and with enlargement of intracytoplasmic membrane compartment. Notably swollen astrocytes were observed in all samples examined. Glycogen-rich and glycogen-depleted astrocytes were identified in anoxic-ischaemic regions. Dark and hydropic satellite, interfascicular and perivascular oligodendrocytes were also found. The status spongiosus of severely oedematous brain parenchyma observed by LM and (S)TEM was correlated with the enlarged extracellular space and disrupted neuropil observed by TEM. The (S)TEM is recommended as a suitable technique for studying pathological processes in the central nervous system and as an informative adjunct to LM and TEM.

Photodegradation of natural organic matter exposed to fluctuating levels of solar radiation

Irradiation of natural water samples with natural or artificial UVR typically results in a progressive loss of color and decreased absorbance; a process often referred to as photobleaching. In a typical photobleaching experiment, samples are exposed to a relatively constant level of artificial or natural UVR. However, under most natural situations, the vertical mixing of the water within the upper mixed layer results in strong and periodic fluctuations in UV irradiance. In this paper, we present the results of an experiment in which natural lake water was exposed to solar radiation in quartz tubes that were incubated either at fixed depths or rotating within the water column. We found differences between rotating and fixed samples in (i) photobleaching, (ii) nutrient release, and (iii) subsequent use by algae and bacteria. The evidence presented in this study demonstrated that photochemical processes might be affected by vertical water motion. The reasons for such differences remain largely unknown. Although we offer a potential explanation for such differences, our proposed mechanism is based on a post-hoc analysis of the data and should be taken solely as a working hypothesis for future research.

Decreased frequency of somatic hypermutation and impaired affinity maturation but intact germinal center formation in mice expressing antisense RNA to DNA polymerase zeta

To examine a role of DNA polymerase zeta in somatic hypermutation, we generated transgenic mice that express antisense RNA to a portion of mouse REV3, the gene encoding this polymerase. These mice express high levels of antisense RNA, significantly reducing the levels of endogenous mouse REV3 transcript. Following immunization to a hapten-protein complex, transgenic mice mounted vigorous Ab responses, accomplished the switch to IgG, and formed numerous germinal centers. However, in most transgenic animals, the generation of high affinity Abs was delayed. In addition, accumulation of somatic mutations in the V(H) genes of memory B cells from transgenic mice was decreased, particularly among those that generate amino acid replacements that enhance affinity of the B cell receptor to the hapten. These data implicate DNA polymerase zeta, a nonreplicative polymerase, in the process of affinity maturation, possibly through a role in somatic hypermutation, clonal selection, or both.

Hormone replacement therapy. Knowledge, attitudes and practices of women attending a gynaecology outpatient clinic in Trinidad

A questionnaire was used to assess the knowledge, attitudes, and practices of a sample of 218 outpatients attending the Port of Spain General Hospital Gynaecology Outpatient Clinic. The questionnaire investigated women's knowledge of menopause, risks and benefits of Hormone Replacement Therapy (HRT), their attitudes concerning HRT and menopause as well as practices of postmenopausal women with respect to HRT. Comparisons were made between women of differing menopausal status, educational background and ethnicity. The results showed that overall knowledge was lacking regardless of menopausal status, ethnicity or educational background. Less educated women were more inclined to believe that HRT was inappropriate principally because they regarded the menopause as a natural process (p = 0.023). Only 24% of postmenopausal women were practicing some form of HRT. A minority (7%) had previously been undergoing the therapy but had stopped. Most postmenopausal women (69%) simply never considered treatment because the majority had never heard about HRT. The main source of patient information was from the clinic they were attending. This study reveals low awareness of menopausal information and therapeutic options in a Trinidadian population. A targeted education programme may substantially fill this void.

Human ClC-3 is not the swelling-activated chloride channel involved in cell volume regulation

Volume regulation is essential for normal cell function. A key component of the cells' response to volume changes is the activation of a channel, which elicits characteristic chloride currents (I(Cl, Swell)). The molecular identity of this channel has been controversial. Most recently, ClC-3, a protein highly homologous to the ClC-4 and ClC-5 channel proteins, has been proposed as being responsible for I(Cl, Swell). Subsequently, however, other reports have suggested that ClC-3 may generate chloride currents with characteristics clearly distinct from I(Cl, Swell). Significantly different tissue distributions for ClC-3 have also been reported, and it has been suggested that two isoforms of ClC-3 may be expressed with differing functions. In this study we generated a series of cell lines expressing variants of ClC-3 to rigorously address the question of whether or not ClC-3 is responsible for I(Cl, Swell). The data demonstrate that ClC-3 is not responsible for I(Cl, Swell) and has no role in regulatory volume decrease, furthermore, ClC-3 is not activated by intracellular calcium and fails to elicit chloride currents under any conditions tested. Expression of ClC-3 was shown to be relatively tissue-specific, with high levels in the central nervous system and kidney, and in contrast to previous reports, is essentially absent from heart. This distribution is also inconsistent with the previous proposed role in cell volume regulation.

Bioelectrical impedance analysis of the body composition of Nigerian children with calcium-deficiency rickets

Children with calcium-deficiency rickets experience increased urinary excretion of both essential and non-essential amino acids compared to non-rachitic children of the same age. Chronic wastage of amino acids into the urine could lead to a deficit in fat-free mass (FFM) in rachitic children. We therefore determined the FFM of children with calcium-deficiency rickets in northern Nigeria using bioelectrical impedance analysis. Because of the leg deformities present in the rachitic subjects, we calculated a 'corrected' height for each rachitic subject using the relationship between arm length and height in non-rachitic subjects over the same age range (r = 0.94). A total of 28 children (4 male and 24 female), 2-9 years of age with calcium-deficiency rickets and an equal number of age- and gender-matched controls were recruited into the study. Resistance and reactance measurements were obtained for all subjects and the total body water was calculated using age-specific equations. FFM was then calculated using age- and gender-specific hydration constants. No significant differences were found in the weights or FFM between the rachitic subjects and the controls (8.41 kg +/- 2.19 vs. 8.85 kg +/- 1.90, respectively). We conclude that chronic urinary wastage of amino acids by rachitic children does not result in a deficit in FFM.

Inflammatory fibroid polyp of the esophagus

The case of a 76-year-old woman with a submucosal tumor of the esophagus, whose principal symptoms were dysphagia and epigastric/retrosternal pain, is reported here. Endoscopy, barium swallow and a CAT scan all pointed to extramucosal localization. The lesion was located in the lower esophagus lying on the stomach fundus. An ulcer in the region of the cardia complicated the tumor. Two sets of conventional biopsies failed to detect malignancy, only inflammation and intestinal metaplasia were seen in the specimens of the mucosa surrounding the ulcer. The endoscopic ultrasonographic findings were an indistinct margin, hypoechogenicity, homogeneous appearance and location within the second and third echographic layer. The surgical resection of the tumor was complemented by an anterior partial fundoplication. The histologic study revealed an inflammatory fibroid polyp, which is a rare, benign, non-capsulated submucosal lesion composed mainly of loose connective tissue and vessels, with an eosinophilic inflammatory component. This lesion is seldom found in the esophagus.

Xanthomonas albilineans Haplotype B Responsible for a Recent Sugarcane Leaf Scald Disease Outbreak in Cuba

Over the past 3 years, the incidence of sugarcane leaf scald disease (LSD) caused by Xanthomonas albilineans has increased at alarming rates in some Caribbean countries. LSD was in latent phase since 1978, when the disease was reported in Cuba, until February 1998 when typical symptoms were observed in germ plasm collections and in some commercial plantings. More than 150 bacterial isolates from different sugarcane varieties and from different localities were isolated on Wilbrink agar medium and characterized. All isolates had shown similar cultural and biochemical patterns. However, serological differences between isolates from the recent outbreak and the ones obtained prior to 1998 were detected by indirect ELISA testing. Differences between Cuban isolates obtained prior to 1998 and those from the recent outbreak were confirmed by analysis of repetitive DNA sequences dispersed throughout the genome. According to the pattern obtained, the newer isolates were similar to reference strains classified as haplotype B by pulsed field gel electrophoresis (1). It is concluded that the recent outbreak of LSD was caused by a strain different than the ones previously detected in Cuba. Reference: (1) M. J. Davis et al. Phytopathology 87:316, 1997.

A shark antibody heavy chain encoded by a nonsomatically rearranged VDJ is preferentially expressed in early development and is convergent with mammalian IgG

In most vertebrate embryos and neonates studied to date unique antigen receptors (antibodies and T cell receptors) are expressed that possess a limited immune repertoire. We have isolated a subclass of IgM, IgM(1gj), from the nurse shark Ginglymostoma cirratum that is preferentially expressed in neonates. The variable (V) region gene encoding the heavy (H) chain underwent V-D-J rearrangement in germ cells ("germline-joined"). Such H chain V genes were discovered over 10 years ago in sharks but until now were not shown to be expressed at appreciable levels; we find expression of H(1gj) in primary and secondary lymphoid tissues early in life, but in adults only in primary lymphoid tissue, which is identified in this work as the epigonal organ. H(1gj) chain associates covalently with light (L) chains and is most similar in sequence to IgM H chains, but like mammalian IgG has three rather than the four IgM constant domains; deletion of the ancestral IgM C2 domain thus defines both IgG and IgM(1gj). Because sharks are the members of the oldest vertebrate class known to possess antibodies, unique or specialized antibodies expressed early in ontogeny in sharks and other vertebrates were likely present at the inception of the adaptive immune system.

Evolution and the molecular basis of somatic hypermutation of antigen receptor genes

Somatic hypermutation of immunoglobulin genes occurs in many vertebrates including sharks, frogs, camels, humans and mice. Similarities among species reveal a common mechanism and these include the AGC/T sequence hot spot, preponderance of base substitutions, a bias towards transitions and strand bias. There are some differences among species, however, that may unveil layers of the mechanism. These include a G:C bias in frog and shark IgM but not in nurse shark antigen receptor (NAR), a high frequency of doublets in NAR hypermutation, and the co-occurrence of somatic hypermutation with gene conversion in some species. Here we argue that some of the similarities and differences among species are best explained by error-prone DNA synthesis by the translesion synthesis DNA polymerase zeta (Pol zeta) and, as suggested by others, induction of DNA synthesis by DNA breaks in antigen receptor variable genes. Finally, targeting of the variable genes is probably obtained via transcription-related elements, and it is the targeting phase of somatic hypermutation that is the most likely to reveal molecules unique to adaptive immunity.

Relative roles of somatic and Darwinian evolution in shaping the antibody response

The need for a highly specific system of recognition in immunity has resulted in the evolution of several somatic mechanisms such as V(D)J recombination, to diversify the repertoire of B cells. Therefore, repertoire diversification is the driving force for the cells that constitute the bulk of the response to unpredictable pathogens, the B2 naive B cells. Predictability of antigen, on the other hand, has played a major role in shaping the neonatal repertoire, in which evolution to recognize commonly encountered pathogens has driven the germline sequence of several VH segments that are used frequently in the neonatal repertoire. A third population, the memory B cell population, is generated to respond to a known pathogen, but predictability of the pathogen is not acquired until after a first exposure. Therefore, it is somatic evolution in germinal centers that drives the generation of high-affinity memory B cells.

Modulation of the startle response and startle laterality in relatives of schizophrenic patients and in subjects with schizotypal personality disorder: evidence of inhibitory deficits

OBJECTIVE

Patients with schizophrenia spectrum disorders have been shown to have deficits in sensorimotor gating as assessed by prepulse inhibition of the startle response. The authors hypothesized that nonschizophrenic relatives of patients with schizophrenia would also have prepulse inhibition deficits, thereby reflecting a genetically transmitted susceptibility to sensorimotor gating deficits.

METHOD

Twenty-five comparison subjects, 23 patients with schizophrenia, 34 relatives of the schizophrenic patients, and 11 subjects with schizotypal personality disorder were assessed in an acoustic startle paradigm. The eye-blink component of the startle response was assessed bilaterally by using electromyographic recordings of orbicularis oculi.

RESULTS

The patients with schizophrenia, their relatives, and subjects with schizotypal personality disorder all had reduced prepulse inhibition relative to comparison subjects, and these deficits were more evident in measures of right eye-blink prepulse inhibition. Comparison subjects demonstrated greater right versus left eye-blink prepulse inhibition, whereas the probands, their relatives, and subjects with schizotypal personality disorder showed less asymmetry of prepulse inhibition.

CONCLUSIONS

These data suggest a genetically transmitted deficit in prepulse inhibition (sensorimotor gating) in patients with schizophrenia spectrum disorders, including subjects with schizotypal personality disorder and relatives of patients with schizophrenia.

Utility of tissue culture for detection of Toxoplasma gondii in vitreous humor of patients diagnosed with toxoplasmic retinochoroiditis

Laboratory recovery and confirmation of the etiologic agent in necrotizing retinochoroiditis are problematic. Tissue culture and intraocular antibody titers were compared as adjuncts to clinical diagnosis for toxoplasmic retinochoroiditis: the correlations were 91 and 67%, respectively. Isolation of Toxoplasma gondii may establish a definitive diagnosis in patients with toxoplasmic retinochoroiditis.

A selective optical sensor based on [9]mercuracarborand-3, a new type of ionophore with a chloride complexing cavity

A highly selective optical sensor for chloride, based on the multidentate Lewis acid ionophore [9]mercuracarborand-3, is described herein. This sensor is constructed by embedding the mercuracarborand ionophore, a suitable pH-sensitive lipophilic dye, and lipophilic cationic sites in a plasticized polymeric membrane. The multiple complementary interactions offered by the preorganized complexing cavity of [9]mercuracarborand-3 is shown to control the anion selectivity pattern of the optical film. The film exhibits a significantly enhanced selectivity for chloride over a variety of lipophilic anions such as perchlorate, nitrate, salicylate, and thiocyanate. Furthermore, the optical selectivity coefficients obtained for chloride over other biologically relevant anions are shown to meet the selectivity requirements for the determination of chloride in physiological fluids, unlike previously reported chloride optical sensors. In addition, the optical film responds to chloride reversibly over a wide dynamic range (16 microM-136 mM) with fast response and recovery times.

L-Carnitine effects on chemical composition of plasma lipoproteins of rabbits fed with normal and high cholesterol diets

L-Carnitine plays an important role in the mitochondrial uptake of long-chain fatty acids in mammals. It has recently been shown that this compound has a marked hypo-cholesterolemic effect when used in conjunction with lipid-rich diets. The aim of this study was to investigate the effects of L-carnitine on the fatty acid composition of plasma lipoproteins in rabbits fed with different diets. Four different groups were investigated: group I (standard diet), group II (standard diet supplemented with L-carnitine at 80 mg/kg), group III (standard diet supplemented with 0.5% cholesterol), and group IV (standard diet supplemented with 0.5% cholesterol plus L-carnitine at 80 mg/kg). The feeding period was 126 d. Total plasma cholesterol was indistinguishable in groups I and II, but increased nearly 40-fold in group III. This increment was reduced by 50% in group IV. Correspondingly, total cholesterol content in lipoprotein fractions [very low density lipoprotein (VLDL), low density lipoprotein (LDL), high density lipoprotein (HDL) separated by agarose gel chromatography was the same for groups I and II, while for animals fed a cholesterol-rich diet (III) total cholesterol in VLDL + LDL increased nearly 100-fold when compared with groups I and II but, again, the increment was reduced by 50% in group IV. In contrast, total cholesterol in HDL increased only fivefold for both groups III and IV when compared with groups I and II, indicating no effects of L-carnitine on this parameter. The reduction of total cholesterol in VLDL + LDL particles in animals fed a cholesterol-rich diet plus L-carnitine was associated with a marked decrease in the ratio of cholesteryl ester to free cholesterol and a dramatic increase in their phospholipid content; opposite effects were observed for HDL. L-Carnitine induced a marked decrease in the saturated to unsaturated C16 + C18 fatty acid ratio in cholesteryl esters associated with VLDL and LDL from animals fed with both normal and cholesterol-rich diets. The opposite effect (a large increase in the saturated to unsaturated fatty acid ratio) was observed for both cholesteryl esters and phospholipids associated with HDL in animals fed with both diets. The results suggested that the hypocholesterolemic effects of L-carnitine could be associated with increased systemic breakdown of cholesteryl esters, a probable increase in reverse cholesterol transport, and the stabilization of a phospholipid-based structure of VLDL + LDL particles.

Liver transplantation in patients with homozygotic familial hypercholesterolemia previously treated by end-to-side portocaval shunt and ileal bypass

Familial hypercholesterolemia is the result of mutations in the gene that encodes the synthesis of the cellular receptor for low density lipoprotein (LDL). In the homozygous form of the disease (HFHC), cellular LDL receptors either do not form, or, when present, cannot bond LDL and mediate its cellular uptake LDL, and the cholesterol that it transports accumulate in plasma, producing severe premature atherosclerosis and death from coronary artery disease usually before the age of 20. Currently, the only effective treatment is liver transplantation, which, alone or in association with medications, normalizes plasma cholesterol levels. The authors report the cases of 2 siblings with HFHC who underwent portocaval shunt at the ages of 2.5 and 1.5 years, respectively. Portocaval shunt produced an immediate, but insufficient decrease in cholesterol (by 40% and 35%, respectively), leaving them with cholesterol concentrations of about 500 mg/dL. One year later they each underwent ileal bypass without obtaining any significant response. Liver transplantation at the ages of 18 and 16 years, respectively, reduced plasma cholesterol concentrations to 129 and 225 mg/dL, respectively. The earlier operations seriously increased the technical difficulty of liver transplantation and did not produce a favorable effect on the natural course of the disease, so portocaval shunt and ileal bypass are not indicated in HFHC, not even for the purpose of delaying liver transplantation.