Characterization of the double-stranded RNA genome segment S3 of avian reovirus

The double-stranded RNA genome segment S3 of avian reovirus (ARV) S1133 was cloned following polyadenylation of both strands and cDNA synthesis of S3 RNA. The complete segment S3 nucleotide sequence was determined. S3 is 1196 base pairs long with one long open reading frame (ORF). The ORF possesses the AUG initiation codon in an optimum context for translation and starts at the first initiation codon (residue 24) and extends for 367 codons, sufficient to encode a protein of the same size as the known S3 gene product, protein sigmaB, one of the major outer capsid proteins of avian reovirus (Mr 41471). Protein sigmaB was subsequently expressed in Escherichia coli. The expressed protein sigmaB was indistinguishable from virion protein sigmaB as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, immunoblot assay, and N-terminal amino acid sequencing of several peptides generated by Staphyloccus aureus V8 protease digestion. ARV S3 genome segment possesses a pentanucleotide UCAUC at the 3'-terminus of its plus strand. The pentanucleotide sequence is common to the other genome segment S1 of ARV and to ten genome segments of mammalian reovirus at the 3'-terminus of their plus strands. Amino acid sequence analysis revealed that ARV sigmaB does not contain a repeated basic amino acid motif as do the three serotypes of mammalian reovirus. The results of amino acid sequencing suggest that the most susceptible cleavage sites of sigmaB to V8 protease are located in a hydrophilic area between amino acids 95 and 140.

Clinical and demographic characteristics of migraine in urban children

OBJECTIVE

To establish the frequency, symptoms, duration, and treatment methods of childhood migraine in an urban area.

DESIGN

Self-administered questionnaire survey. The questionnaire was designed according to criteria suggested by the International Headache Society (IHS).

PARTICIPANTS

In 1994, with the help of school officials in 41 elementary and middle schools in the Greater Cleve-land Area, 18,000 questionnaires were distributed to the parents of schoolchildren who ranged in age from 5 to 13 years.

RESULTS

Of the total 2572 respondents, 222 children (8.6%) met the IHS criteria for migraine. Male to female ratio was 1:1.2 (99:120), 65.8% had a positive family history of migraine, 30.6% had onset of migraine at 4 to 5 years of age, and 54.1% reported having an aura (71% of these were visual aura). The headaches were mostly pulsating, poorly localized, lasted about 2 to 12 hours, and were aggravated by motion, noise, and bright light. The associated symptoms were nausea, vomiting, photophobia, and phonophobia. During the attack, 43% of the migraineurs had to stay in bed, and 27% were unable to attend school. Only 19.8% of the migraineurs were diagnosed to have migraine by their physicians, and most of these had not received treatment.

CONCLUSION

This study in an urban area indicates that childhood migraine is a common, often underdiagnosed disorder that causes significant suffering for children and their families.

Gene targeting of a CFTR allele in HT29 human epithelial cells

HT29 cells endogenously express the cystic fibrosis transmembrane conductance regulator (CFTR) and have been used previously as a model to examine cellular regulation of CFTR expression and chloride secretory function. Homologous recombination has been used to specifically disrupt CFTR transcription in the HT29-18-C1 subclone. Experiments demonstrate successful disruption of a CFTR allele by DNA constructs, which target insertion of the neomycin phosphotransferase gene into CFTR exon 1 via homologous recombination. The mutation of one allele is a partial knockout because this cell line has multiple CFTR alleles. The mutation is confirmed by polymerase chain reaction (PCR) and genomic Southern blot analysis. A 52-68% reduction in CFTR mRNA levels is observed in the mutant cell line by both Northern and PCR analysis. However, Western blots show no decrease in total CFTR protein levels. Consistent with the lack of reduction in CFTR protein, the partial knockout mutant does not demonstrate alterations in cyclic AMP or calcium stimulation of chloride efflux or net osmolyte loss. Results suggest that posttranscriptional regulation of CFTR levels may contribute to maintenance of cellular chloride transport function.

Utility of a standardized sign-out card for new medical interns

Conscientious sign-out between medical interns is important for the continuity of care of hospitalized patients. We developed a standardized sign-out card that prompted the intern going off duty to transmit patient care information to the inter on call. The card was tested in a prospective, randomized, controlled trial in which one group of interns used the card, and another group did not. Any instance of poor sign-out was reported on a questionnaire completed by the intern who had been on call the previous night. The group using the sign-out cards reported poor sign-out on 8 nights (5.8% of questionnaires), and the control group reported it on 17 nights (14.9% of questionnaires, p = .016). The card was time-effective and inexpensive, resulted in more complete data recording, and possibly decreased the morbidity associated with poor sign-out.

Effects of self-induced mental imagery on autonomic reactivity in children

The purposes of this research study were: (1) to determine whether changes in cardiac rate, skin temperature, and/or electrodermal activity occur as children change mental imagery and (2) to determine whether such changes are related to age, sex, or other variables. Children who were evaluated in this study had no previous experience with hypnosis or biofeedback training and were in good health with no learning disabilities. Thirty-eight boys and 38 girls ranging in age from 5 to 15 years were studied in a comfortable setting with a constant room temperature and biofeedback equipment. A Procomp 5DX computer software unit was used to measure autonomic reactivity during baseline and mental processing periods. After baseline monitoring indicated stabilization of autonomic measures, each child was asked to think about being in a quiet, pleasant place for 120 seconds. Pulse rate, skin temperature, and electrodermal activity were recorded. A resting period followed, and each child was then asked to think about an exciting activity, such as a preferred sports activity, for another 120 seconds. At the end of this monitoring, each child was asked to describe what had been his/her mental imagery during the two monitoring periods. Data analysis used paired t tests and repeated measures analysis of variance. For all children, the pulse rates showed significant decreases (p < .001) during quiet and relaxing imagery and significant increases (p < .001) during active imagery. Skin temperatures increased significantly (p < .001) during quiet imagery and active imagery, whereas electrodermal activity decreased (p < .001) during active imagery. Observed changes did not relate to age or sex. The results confirm our clinical observations that deliberate changing of mental imagery by children results in immediate autonomic changes. Questions evolving from this study and similar studies done in adults are: (1) Do average-thinking processes impact on autonomic changes over long periods of time and (2) do these changes ultimately impact on health, such as cardiovascular status?

Exacerbation of hepatitis in hepatitis B carriers following chemotherapy for haematological malignancies

We describe nine asymptomatic chronic carriers of hepatitis B virus, four males and five females, with a mean age of forty-six years and all were Chinese, who developed exacerbation of hepatitis following chemotherapy for haematological malignancies. Seven patients had non-Hodgkin's lymphoma of whom three were treated with MACOP-B, two with BCEPP, one with PROMACE-CYTABOM and one with CHOP. Two patients had acute myeloid leukaemia and were treated with daunorubicin and cytosine arabinoside. Exacerbation of hepatitis occurred between one to four weeks following the last course of chemotherapy in eight patients. Two patients developed exacerbation of hepatitis when the dosage of prednisolone was reduced after they had ten weeks of high dose prednisolone. The outcome was fatal in six patients; all of whom developed hepatic encephalopathy. In four of these patients, alanine transaminase levels exceeded 1000 iu/l. Cytotoxic and immunosuppressive therapy permit enhanced viral replication. Withdrawal of the drugs results in partial restoration of immunocompetence and leads to rapid destruction of hepatocytes with consequent hepatic necrosis. Hence, patients who are hepatitis B virus carriers undergoing chemotherapy should be closely monitored. The fatal outcome of reactivation of chronic hepatitis B virus warrants prospective trials addressing preventive measures.

Avian retroviral RNA element promotes unspliced RNA accumulation in the cytoplasm

All retroviruses need mechanisms for nucleocytoplasmic export of their unspliced RNA and for maintenance of this RNA in the cytoplasm, where it is either translated to produce Gag and Pol proteins or packaged into viral particles. The complex retroviruses encode Rev or Rex regulatory proteins, which interact with cis-acting viral sequences to promote cytoplasmic expression of incompletely spliced viral RNAs. Since the simple retroviruses do not encode regulatory proteins, we proposed that they might contain cis-acting sequences that could interact with cellular Rev-like proteins. To test this possibility, we initially looked for a cis-acting sequence in avian retroviruses that could substitute for Rev and the Rev response element in human immunodeficiency virus type 1 expression constructs. A cis-acting element in the 3' untranslated region of Rous sarcoma virus (RSV) RNA was found to promote Rev-independent expression of human immunodeficiency virus type 1 Gag proteins. This element was mapped between RSV nucleotides 8770 and 8925 and includes one copy of the direct repeat (DR) sequences flanking the RSV src gene; similar activity was observed for the upstream DR. To address the function of this element in RSV, both copies of the DR sequence were deleted. Subsequently, each DR sequence was inserted separately back into this deleted construct. While the viral construct lacking both DR sequences failed to replicate, constructs containing either the upstream or downstream DR replicated well. In the absence of both DRs, Gag protein levels were severely diminished and cytoplasmic levels of unspliced viral RNA were significantly reduced; replacement of either DR sequence led to normal levels of Gag protein and cytoplasmic unspliced RNA.

The role of labetalol and propofol in the management of HELLP syndrome--a case report

The acronym HELLP describes a syndrome of (H) hemolysis, (EL) elevated liver enzymes, and (LP) low platelets, which symptomatically defines a unique group of preeclamptic/eclamptic women. Pregnancies complicated by this syndrome are associated with poor maternal and fetal outcome. This poses a considerable challenge to the anesthesiologists as many of these patients require emergent Cesarean section. We reported a 30-year-old woman with gestation of 32 wk who sustained Cesarean section under the impression of pregnancy with HELLP syndrome. General anesthesia was performed for this patient. The preoperative evaluation, general management, and intraoperative monitoring system were described. The individual role and use of labetalol and propofol were also discussed in this report.

Long-term propofol infusion and airway management in a patient with Goldenhar's syndrome

A 2-year-old patient of Goldenhar's syndrome received an operation for corneal transplantation. Difficult endotracheal intubation from the congenital anomaly was treated with laryngeal mask airway and pediatric fiberoptic laryngoscope. Long-term propofol infusion (> 10 h) for anaesthetic maintenance in this small child was used with rapid and smooth recovery.

Respiratory nuclei share synaptic connectivity with pontine reticular regions regulating REM sleep

Injection of cholinomimetics into the medial pontine reticular formation (mPRF) of intact, unanesthetized cat causes a rapid eye movement (REM) sleep-like state and respiratory depression. The mPRF contains no concentrations of respiratory neurons, and this study examined the hypothesis that respiratory depression evoked from the mPRF is synaptically mediated. The mPRF of conscious cats was injected with bethanechol to define an mPRF zone causing state-dependent respiratory depression. Bethanechol caused a 361% increase in the REM sleep-like state and a 37% decrease in minute ventilation. Additional cats were injected with the retrograde fluorescent tracers True Blue and either Fluoro-Gold or Diamidino Yellow aimed for the cholinoceptive mPRF or for the pontine respiratory group (PRG). After mPRF dye injection, 1) labeling was observed in the PRG, dorsal respiratory group (DRG), and ventral respiratory group (VRG); and 2) double-labeled cells were observed in the VRG and PRG. Dye injections into the PRG produced contralateral and ipsilateral fluorescent labeling of the mPRF, DRG, and VRG. Thus cholinoceptive regions of the mPRF involved in REM sleep generation have reciprocal monosynaptic connections with the PRG and receive monosynaptic projections from the DRG and VRG.

Haemophagocytosis in bone marrow aspirate--a review of the clinical course of 10 cases

The clinical course of 10 cases where marrow aspirate showed features of haemophagocytosis was reviewed. Eight of these had a fulminant clinical course characterized by high fever, constitutional symptoms, wasting, hepatosplenomegaly with liver dysfunction, sometimes lymphadenopathy, progressive pancytopenia and coagulopathy, like that described as 'malignant histiocytosis' in the past. The remaining 2 cases did not have this classical clinical syndrome. Among the former 8 cases, 4 of them had high-grade lymphoma, 3 of whom were confirmed to be peripheral T cell lymphoma. Three of the remaining 4 had suspicious lymphomatous infiltrate on marrow trephine. In every case an extensive search for viral etiology by serology was negative. The 2 cases which did not have fulminant clinical feature were found to have lymphoma of the diffuse large cell and Ki-1 anaplastic type, respectively. A review of the literature reveal that most cases with haemophagocytic syndrome have a fulminant clinical course and are peripheral T cell lymphoma, which generally has a poor prognosis. In our study, the 8 cases with the classical haemophagocytic syndrome had a median survival of 24 days and a long-term survival of 37.5% at 28 months. Prompt initiation of chemotherapy is a life-saving measure and the only chance of achieving a long-term survival in patients with haemophagocytic syndrome if the underlying lymphoma can be diagnosed early.

Altered platelet phospholipid-dependent thrombin generation in thrombocytopenia and thrombocytosis

Platelet phospholipid dependent thrombin generation was determined in 20 patients with thrombocytosis, 18 with thrombocytopenia, and 25 normal controls, using a quantitative chromogenic assay. Platelets from patients with myeloproliferative disorders displayed normal lag times to 20 nM thrombin concentration but increased thrombin potentials, even when corrected for platelet size. Platelets from patients with reactive thrombocytosis supported normal thrombin generation. ITP platelets were large, with a proportionate increase in thrombin potentials, but very short lag times to 20 nM thrombin concentration. Following marrow ablation there was a progressive loss of activation-induced enhancement of thrombin generation. Platelets from patients with idiopathic aplastic anaemia supported normal thrombin generation. These findings indicate that platelet phospholipid-dependent thrombin generation is altered in many patients with a variety of quantitative platelet disorders, and this may be an important determinant of the clinical expression of these disorders.

Haemostasis associated with liver disease and liver transplantation

The production and regulation of components of haemostasis is largely dependent on liver function. Liver disease is associated with alteration of the coagulant:anticoagulant and fibrinolytic:antifibrinolytic balance as well as quantitative and qualitative alterations of the cellular components of haemostasis. In this article we have reviewed the nature and frequency of disturbed haemostatic function in patients with acute and chronic liver disease and during liver transplantation. The risk of haemorrhage and thrombosis, and mechanisms leading to these complications are reviewed and treatment strategies utilising blood component therapy and pharmacological manipulation of the coagulant and fibrinolytic systems are proposed. Finally, areas for further study are suggested so that rational effective therapeutic strategies can be developed.

Heat shock- and alkaline pH-induced proteins of Campylobacter jejuni: characterization and immunological properties

The protein response to physiological stress was characterized in Campylobacter jejuni 81176 after exposure to heat and pH shock and following periods of recovery. Immunoreactivities of major stress-related proteins were determined with anti-Campylobacter immune rabbit serum and intestinal lavage fluid. Distinct proteins with molecular masses ranging from 10 to 120 kDa were induced and/or released by selective heat or pH treatments. The most notable responses were those of two proteins with apparent molecular masses of 45 and 64 kDa that were induced and two other proteins of 10 and 12 kDa that were released by selective heat shock, alkaline pH treatment, or both. On the basis of N-terminal sequence analysis and immunological cross-reactivity data, the 64- and 10-kDa proteins were the C. jejuni homologs of Escherichia coli GroEL and GroES proteins, respectively. Enhanced chemiluminescence Western blotting (immunoblotting) revealed that all four proteins were among the major protein antigens recognized by anti-Campylobacter rabbit serum immunoglobulin G (IgG) and immune rabbit intestinal lavage IgA (secretory IgA). The results of this investigation suggest that the C. jejuni 10-, 12-, 45-, and 64-kDa proteins and a number of minor stress-related proteins deserve further evaluation of their respective roles in Campylobacter pathogenesis and immunity.

Comparison of the labeled avidin-biotin and the conventional enzyme-linked immunosorbent assay for detecting antibody to reovirus in chickens

A labeled avidin-biotin enzyme-linked immunosorbent assay (LAB-ELISA) for detecting antibodies to avian reovirus (ARV) in chicken sera was developed and compared with conventional ELISA. Purified ARV, biotin-labeled rabbit anti-chicken IgG conjugate, and horseradish peroxidase-labeled avidin were used in the LAB-ELISA. The two types of ELISA had the similar ability to clearly distinguish ARV-positive and -negative sera. Furthermore, non-specific reactions with the two ELISAs against sera from ARV-negative chickens were reduced markedly. When sera from farm chickens were tested by the two ELISAs and serum neutralization (SN), the correlation rates between SN and conventional ELISA, and SN and LAB-ELISA were similar and were 93.4% and 92.3%, respectively.

Markers of thrombin and plasmin generation in patients with inherited thrombophilia

AIM

To determine the prevalence of a biochemically detectable hypercoagulable state, defined in terms of increased thrombin or plasmin generation, in patients with phenotypically characterised thrombophilia.

METHODS

Plasma concentrations of the prothrombin activation peptide F1.2 and fibrin degradation (FbDP) and fibrinogen degradation products (FgDP) were measured by enzyme immunoassay in 104 patients deficient in natural anticoagulants, and 35 unaffected relatives.

RESULTS

Increased concentrations of F1.2, FbDP, and FgDP were present in 18, 25, and 19 of 104 patients, respectively. There were no correlations between F1.2, FbDP, and FgDP concentrations, or between these parameters and concentrations of natural anticoagulants except for a negative correlation between protein C concentrations and FgDP (rho = -0.46, p = 0.009).

CONCLUSION

A biochemically detectable hypercoagulable state is present in some patients with asymptomatic thrombophilia. Markers of plasmin generation may be increased more frequently in thrombophilia than markers of thrombin generation. This finding should prompt the inclusion of markers of plasmin generation in prospective longitudinal cohort studies to determine the predictive value of a hypercoagulable state, defined by either excessive thrombin or plasmin generation, for the development of venous thromboembolism.

Analysis of the double-stranded RNA genome segments among avian reovirus field isolates

Nine isolates of avian reovirus (ARV) from both healthy birds and birds with different clinical illness and one commercially available vaccine strain were selected and characterized by analysis of the migration pattern of their genomic double-stranded RNA (dsRNA) segments following separation by polyacrylamide gel electrophoresis. Different electropherotypes were observed and analyzed. The results show that the dsRNA segments of ARV were markedly polymorphic among isolates within the same serotype as well as among different serotypes. The results also show no correlation between electropherotype and disease state.

Single-tube, noninterrupted reverse transcription-PCR for detection of infectious bursal disease virus

An assay protocol based on single-tube, noninterrupted reverse transcription-PCR (RT-PCR) for the detection of infectious bursal disease virus (IBDV) is described. After the conditions for RT-PCR had been optimized, a primer set framing a region within the gene coding for IBDV VP2 protein was used to amplify a 318-bp fragment of the IBDV genome. Amplified product was detected with three strains of IBDV, whereas none was obtained from uninfected bursal tissue or seven unrelated avian viruses. The sensitivity of this RT-PCR was tested with purified viral RNA from three strains of IBDV. The detection limit was 10 fg in an ethidium bromide-stained gel. In addition, this assay system was used to detect IBDV in bursal-tissue specimens from commercially reared chickens. The identity of the amplified products from the tissue specimen preparation was determined by using a rapid, simple procedure in which internally nested, end-labeled probes were used.

Developmental toxicity of OTTO Fuel II in the rat and rabbit

OTTO Fuel II (OFII) is a propellent used by the United States Navy in its Mk 46 and Mk 48 torpedoes. Owing to the possibility of human exposure during fueling and defueling operations, studies were initiated to determine if OFII was a developmental toxin. Phase I of the investigation involved dosing four groups of time-mated Fischer-344 rats with OFII. The fuel was administered dermally at the rate of 0, 400, 2000 and 4000 mg kg-1 day-1. A significant reduction in body weight was seen at necropsy in dams receiving 2000 and 4000 mg kg-1 day-1 of OFII. Fetuses from these dams also weighed significantly less than control fetuses. Phase II of the investigation involved dosing of artificially inseminated rabbits with OFII. The fuel was administered to the skin of the animal's back at the rate of 0, 100, 316 and 1000 mg kg-1 day-1. Maternal toxicity was evidenced by a significant reduction in body weight of the dams in the 1000 mg kg-1 day-1 dose group on days 20 and 25 of gestation. There were no significant differences observed in maternal weight or fetal weight at necropsy. Morphological examination of both rat and rabbit fetuses failed to reveal significant evidence of fetal malformations.

Detection of infectious bursal disease virus infection using the polymerase chain reaction

The method of reverse transcription (RT) followed by the polymerase chain reaction (PCR) was used to amplify two different fragments of the infectious bursal disease virus (IBDV) genome. Two sets of primer framed two different regions within the genes coding for proteins VP2 and VP3, respectively. Both sequences were detected in five strains of IBDV, whereas, none were obtained from uninfected control cells. The sensitivity of RT-PCR was carried out on nucleic acids from the IBDV infected cell cultures. The detection limit was 10(0) to 10(-1) TCID50 in ethidium bromide stained gels and could be enhanced further to 10(-1) to 10(-3) TCID50 by hybridization after southern transfer. In addition, detection of IBDV infection in 12 out of 14 bursal specimens examined by this technique was shown to be entirely consistent with the clinical history and an alternative diagnostic method. The speed, sensitivity, and specificity of this method is relevant for the diagnosis of infection with IBDV.

Acute toxicity, distribution, and metabolism of 2,4,6-trinitrophenol (picric acid) in Fischer 344 rats

Picric acid (2,4,6-trinitrophenol) is widely used in industry, by the military, and as a research/clinical chemistry reagent. Characterization of the toxicity of this chemical has been limited. Thus the acute toxicity, distribution, and metabolism of picric acid were investigated using Fischer 344 rats. The LD50 for picric acid following oral dosing of male and female rats was established as 290 and 200 mg/kg, respectively. Blood gas analysis indicated severe acidosis during acute intoxication. Metabolism of picric acid was limited to reduction of nitro groups to amines. Metabolites isolated from urine included N-acetylisopicramic acid (14.8%), picramic acid (18.5%), N-acetylpicramic acid (4.7%), and unidentified components (2.4%). Approximately 60% of the parent picric acid was excreted unchanged. The plasma half-life for picric acid was 13.4 h with a gut absorption coefficient (ka) of 0.069 h-1. Twenty-four hours following oral administration of [14C]picric acid (100 mg/kg), the primary depots of radioactivity (per gram tissue basis) were blood, spleen, kidney, liver, lung, and testes. Respective tissue/blood ratios were 0.37, 0.31, 0.28, 0.26, and 0.22. All other tissue assayed had partition ratios < 0.20, with brain and adipose tissue having the least amount of radioactivity. Tissue/blood ratios were essentially maintained over a 48-h postadministration period. Binding (in vitro) of [14C]picric acid to plasma proteins (whole blood preparations) demonstrated both high- and low-affinity binding sites, with dissociation constants of 3.18 x 10(-6) and 2.85 x 10(-4) M, respectively. The findings of this investigation provide information on the acute toxicity, metabolism, and distribution of picric acid, which can be used in risk assessment analyses and in the design of subchronic and chronic toxicity tests.

Characterization of nonradioactive hybridization probes for detecting infectious bursal disease virus

Reverse transcription followed by the polymerase chain reaction was used to amplify a fragment of infectious bursal disease virus (IBDV) strain P3009 genome. The amplified DNA fragment was annealed into the plasmid pUC18 and used to transform Escherichia coli strain JM109. A clone that contained IBDV-specific nucleotide sequences was selected and designated pC23. The DNA fragment within pC23 was 320 base pairs in length and designated C23. Radiolabeled probes prepared from C23 hybridized to genome segment A of strain P3009 by a northern-blot hybridization assay. Biotin-labeled probes prepared from C23 and pC23 either by using nick translation (designated C23/NT and pC23/NT, respectively) or by direct introduction of biotin molecules into C23 and pC32 (designated C23/BH and pC23/BH, respectively) were used in the dot blot hybridization assay for detecting IBDV strains. All four biotinylated probes detected three serotype 1 viruses and one serotype 2 IBDV. However, they did not cross-react with nucleic acids extracted from mock-infected cells or from seven unrelated avian viruses. Probe pC23/BH detected as little as 0.04 ng of IBDV RNA, while the other three probes were less sensitive and detected approximately 1 ng of IBDV RNA. In addition, the probe pC23/BH detected IBDV RNA in bursa tissues from commercial broiler raising farms following the dot blot hybridization.

A monoclonal antibody capture enzyme-linked immunosorbent assay for detecting antibodies to infectious bursal disease virus

A monoclonal antibody capture enzyme-linked immunosorbent assay (mAb-ELISA) for antibodies to infectious bursal disease virus (IBDV) in chicken sera was developed and compared with conventional ELISA. When sera from farm chickens were tested by the two ELISAs and serum neutralization (SN), the correlation rate between SN and mAb-ELISA was 100% (49/49), and that between SN and conventional ELISA was 81.6% (40/49). In mAb-ELISA, all of the sera that were antibody-negative by SN had low absorbance values (below 0.05), and the absorbance values correlated closely with the SN titers. In the conventional ELISA, however, the sera antibody-negative by SN had various absorbance values ranging from 0.06 to 0.32. mAb-ELISA had much lower non-specific reactions than the conventional ELISA against sera from IBD-negative chickens.

Long-term survival of mouse corpus callosum grafts in neonatal rat recipients, and the effect of host sensitization

Previous studies have suggested that the incidence of spontaneous rejection among immunogenetically mismatched neural transplants in neonatal recipients varies significantly depending on the cellular composition of the graft material. For example, neuron-rich grafts of embryonic mouse retina generally survive for extended periods without showing signs of rejection after implantation into neonatal rats, whereas cortical xenografts, which contain abundant glial and endothelial cells as well as neurons, typically undergo rejection 4-6 weeks after implantation. To determine whether the presence of donor glia is responsible for this high incidence of spontaneous rejection, we examined the fate of a non-neuronal graft material composed predominantly of xenogeneic glial cells (post-natal day 3, PD3, CD-1 mouse corpus callosum) implanted into the mesencephalon of PD1 Sprague-Dawley rats. The distribution and survival of donor astrocytes were assessed using a monoclonal antibody specific for a mouse astrocyte surface antigen, M2. Thirteen of 16 animals sacrificed within 2 months of implantation had detectable transplants. In these animals, M2-positive cells frequently migrated well away from body of the graft, clustering in large numbers in several characteristic regions of the host brain. Unlike cortical grafts of similar age, the vast majority (93%) of callosal transplants showed no histological signs of rejection or major histocompatibility complex antigen expression in and around the transplant-derived cells. As previously noted in the neonatal retinal transplant paradigm, however, well-integrated 1-month-old corpus callosum grafts could be induced to reject by appropriate sensitization of the host immune system, implying that the host was not immunologically tolerant to the foreign neural graft. With longer survival times in unsensitized hosts, a progressively smaller percentage of animals had detectable donor astrocytes (5 of 10 animals at 3 months postimplantation and 4 of 16 animals at 4 months); in those 9 animals with surviving grafts, only small numbers of M2-positive cells were seen within the graft bed and surrounding host brain. However, only 2 of the 26 "long-term" animals showed evidence of graft rejection. These results indicate that mouse astrocytes show characteristic patterns of migration into the host brain when implanted into neonatal rats; however, these xenogeneic cells have a limited duration of survival. The infrequency with which even subtle signs of spontaneous rejection were detected in animals that had received corpus callosum xenografts suggests that an immune-mediated process is unlikely to be responsible for the time-dependent elimination of the donor astrocytes.(ABSTRACT TRUNCATED AT 400 WORDS)

Monoclonal antibodies against different epitopes of a 40 Kd capsid protein of infectious bursal disease viruses

Nine monoclonal antibodies (Mab) against a 40 Kd capsid protein of infectious bursal disease virus (IBDV) strain P3009 were isolated. They were characterized by enzyme-linked immunosorbent assay, indirect fluorescent antibody staining and virus neutralization. They were divided into two groups concerning virus neutralization. Group I Mabs were able to neutralize virus infectivity; however, group II Mabs were not. Competitive binding assays using these Mabs demonstrated the existence of two distinct antigenic regions (A and B) on the 40 Kd protein. Region A was recognized by group I Mabs and region B was by group II Mabs. The binding reaction with group I Mabs was affected by denaturing of the viral proteins, indicating that the antigenic region involving neutralization was conformation-dependent. The results of enzyme-linked immunosorbent assays and virus neutralization tests suggested that group I Mabs might react with one epitope within region A and group II Mabs with 2 or 3 epitopes within region B.

Timing and patterns of astrocyte migration from xenogeneic transplants of the cortex and corpus callosum

The timing, pattern, and pathway of astrocyte migration were investigated in vivo by transplantation of CD-1 mouse cerebral cortex (E13-14) or corpus callosum (P2-3) into neonatal rat cortex. A monoclonal antibody specific for a mouse astrocyte surface antigen (M2) was used to identify the location of the grafts and the migrated donor astrocytes. Within the host cortex, astrocytes from cortical grafts began migration at post-transplantation day (PTD) 7. Over the next 4 days, the most distant displaced donor cells were found progressively further away from the grafts, migrating at a rate of about 220 microns/day. After PTD 11, the migration rate for the farthest displaced donor cells slowed to 25 microns/day, and the cells appeared to stop at about PTD 16 at a distance of 1,100 microns from the edge of the graft. Astrocytes had a faster migration speed in the white matter and covered a longer distance (5 mm) than those in the gray matter, extending on occasion into the contralateral hemisphere. The patterns of astrocyte migration differed depending on local cues around the transplant. Donor astrocytes that had been implanted into the host cortex migrated toward the host cortical surface, sometimes in several radial lines. Astrocytes from grafts, especially callosal grafts, placed in the subcortical white matter migrated along the host fiber tracts. Many astrocytes transplanted into the hippocampus formed laminar patterns close to the hippocampal neuronal layers. These results suggest that the direction, pattern, and speed of astrocyte migration are influenced by local substrates in the host brain.

tri-n-Butyltin: a membrane toxicant

Increased use of the biocidal compound tri-n-butyltin (TBT) in antifouling paints has prompted research aimed at determining the mechanism for TBT toxicity. Past investigations indicate that the primary cellular target for TBT is the cell membrane. Erythrocyte suspensions treated with TBT concentrations 2 greater than or equal to 5 microM undergo hemolysis described by a sigmoidal kinetic pattern. Transformation of cell shape from discocyte to echinocyte occurs at TBT concentrations greater than or equal to 0.1 microM, indicating that the compound enters the outer membrane bilayer. TBT at concentrations greater than or equal to 10 microM forms electron-dense aggregates that are intercalated within plasma membranes as viewed in ultrathin sections by transmission electron microscopy. Qualitative X-ray microanalysis of these aggregates confirms the presence of tin. The size of these structures can be modified by either 10 mM cyanide or 2,3-dimercaptopropanol (British Anti-Lewisite, BAL). Adding 10 mM cyanide to hemolytic TBT concentrations resulted in a synergistic stimulation of hemolysis attributable to high cyanide anion concentrations in or near the cell membrane. The elevated cyanide anion levels are thought to contribute to membrane lysis. The lipophilic dimercapto compounds BAL, dithiothreitol, and 2,3-dimercaptosuccinate are effective inhibitors of TBT-induced lysis. Water-soluble 2,3-dimercapto-1-propane sulfonate, a BAL analog, was largely ineffective as an inhibitor. The detailed molecular mechanism for TBT-induced membrane lysis is not yet clear. Cellular ATP depletion could be induced by TBT as well as by delipidation of anionic phospholipids or even formation of tributylstannylperoxy radicals, resulting in lipid peroxidation.

Organotin-induced hemolysis, shape transformation and intramembranous aggregates in human erythrocytes

Organotin compounds examined in this study exhibited a relative order of potency for induction of in vitro hemolysis in human erythrocytes as follows: tri-n-butyltin greater than tri-n-propyltin greater than tetra-n-butyltin greater than triphenyltin chloride greater than tri-n-ethyltin bromide greater than dibutyltin dichloride greater than stannous chloride greater than tri-n-methyltin chloride = butyltin chloride dihydroxide. All of the organotin compounds induced erythrocyte shape transformation from the normal discocyte to an echinocyte and, in addition, triphenyltin chloride, tetra-n-butyltin and tri-n-ethyltin bromide also elicited stomatocyte formation at higher concentrations. Select organotin compounds also formed tin-containing aggregates within the plasma membrane. The relative order of effectiveness for organotin induction of intramembranous aggregates was tri-n-butyltin greater than tri-n-propyltin greater than tetra-n-butyltin greater than tri-n-ethyltin bromide, which was based upon the lowest concentration at which they were observed. These results support the previously suggested theory that organotins are membrane effectors because of their comparatively high hydrophobic, lipid partitioning properties. The relatively lipophilic compound, triphenyltin chloride, appeared to be anomalous because it did not readily promote hemolysis or induce the formation of intramembranous aggregates in human erythrocytes. A log-linear statistical model demonstrated an association of hemolysis with both tri-n-butyltin aggregate formation and shape transformation. Select organotin compounds should be useful probes in membrane studies because of their numerous effects.

Inhibition of tributyltin mediated hemolysis by mercapto compounds

Hydrophobic tributyltin (TBT) compounds at concentrations greater than 10 microM caused hemolysis of human erythrocytes and formed structures in plasma membranes. The mercapto compounds, beta-mercaptoethanol (beta MER), 2,3-dimercaptopropanol (BAL), 2,3-dimercapto-1-propane sulfonate (DMPS), DL-dithiothreitol (DTT), and meso-2,3-dimercaptosuccinic acid (DMSA) were examined for their ability to inhibit TBT mediated hemolysis. The relative order of effectiveness for inhibition of TBT mediated hemolysis was BAL greater than DTT greater than DMSA greater than DMPS greater than beta MER. A four-fold excess of BAL over TBT prevented hemolysis for 4 hrs and addition of BAL 0.5 hr after TBT reduced the rate of hemolysis. The number of membrane associated TBT aggregates observed per cell profile decreased as the BAL concentration increased from 0 to 100 microM. However, the mean diameter of TBT aggregates nearly doubled in erythrocyte suspensions at 100 microM BAL. Reactions of dimercapto compounds with lipophilic TBT aggregates may depend on their relative lipid solubilities. Also, conversion of the weak Lewis acid, TBT, from a four to a five or six-coordinate tin adduct by the dimercapto Lewis bases used could also be a factor slowing hemolysis rates.

Cyanide stimulation of tri-N-butyltin mediated hemolysis

The effects of tributyltin and sodium cyanide on hemolysis in human erythrocytes are described. Tributyltin has a sharp cut-off concentration for induction of hemolysis. A 5 microM concentration of tributyltin induces hemolysis and 1 microM or less does not in erythrocyte suspensions with 2.3 X 10(8) cells per ml. The kinetics for tributyltin-induced hemolysis are sigmoidal indicating a complex molecular mechanism leading to lysis. Ten mM sodium cyanide plus 1 microM tributyltin does not stimulate hemolysis rates above levels observed with 10 mM sodium cyanide alone. Five mM sodium cyanide plus hemolytic concentrations of tributyltin stimulates hemolysis rates synergistically compared with either cyanide or tributyltin alone. Ultrastructurally, hemolytic concentrations of tributyltin can be visualized in the electron microscope by osmium staining during fixation as electron-dense spheres penetrating the lipid bilayer of the erythrocyte plasma membrane. Ten mM sodium cyanide plus 25 microM tributyltin increases slightly the size of osmiophilic structures in erythrocyte membranes compared with those spheres seen in cells exposed to 25 microM tributyltin alone. Sodium cyanide is the only compound tested that stimulates tributyltin-induced hemolysis. Sodium thiocyanate, previously shown to be rapidly exchanged across erythrocyte membranes by tributyltin, reduces the rate of hemolysis. It is likely that sodium cyanide stimulates hemolysis in the presence of hemolytic tributyltin concentrations because the multimolecular, membrane-intercalated, tributyltin aggregates are transporting cyanide anion by the electrically silent, anion exchange mechanism demonstrated for other anions. It is suggested that this mechanism delivers cyanide anion to or near critical membrane sites where it is available for enzyme inhibition or cross-linking of protein sulfhydryl groups.

Interspecies variability in propylene glycol dinitrate-induced methemoglobin formation

Interspecies variability of propylene glycol dinitrate (PGDN)-induced methemoglobin formation was studied in vitro employing erythrocytes from four separate species. The net rate of methemoglobin formation was significantly different among species with dog greater than guinea pig greater than rat greater than or equal to human. This order of susceptibility was maintained in stroma-free hemolysates, indicating that interspecies variability was not a reflection of differences in red cell membrane permeability or intracellular transport of PGDN. The erythrocytic enzymes, catalase, superoxide dismutase, glutathione peroxidase, 6-phosphogluconate dehydrogenase, glucose-6-phosphate dehydrogenase, methemoglobin reductase, and glutathione-S-transferase, were assayed by adaptation of existing methods to a centrifugal analyzer. The above enzymes were removed from hemoglobin derived from each species and the order of susceptibility to PGDN-induced methemoglobin formation remained essentially the same with dog greater than guinea pig greater than human = rat. However, the net rate of PGDN-mediated oxidation of hemoglobin to methemoglobin increased in purified hemoglobin preparations from each species. These results demonstrate that there is species variability in the net rate of PGDN-mediated methemoglobin formation. Total enzyme activity in erythrocytes may contribute to reduction in the net rate of methemoglobin formation. However, the primary determinant of the net rate of methemoglobin formation induced by PGDN appears to be the structure of each hemoglobin molecule.

Aspiration biopsy of the kidney. Simultaneous collection of cytologic and histologic specimens

Aspiration biopsy of mass lesions of the kidney is a diagnostic procedure whose potential benefit to patients with equivocal radiologic findings, suspected metastases, palpable flank masses, nonfunctioning kidneys and even cortical cysts has not been fully explored. Over the past 7 years 163 renal aspiration specimens from 152 patients have been examined. Diagnostic yield was enhanced by use of modified "fine" needles with notched tips so that tissue fragments for histology as well as smears for cytology were obtained in 89% of solid tumors. The availability of aspirated tissue contributed significantly to pathologic classification and often spared patients additional surgery for confirmation of the cytologic diagnosis. Among the 152 cases, there were 35 with renal cell carcinomas, a sufficient number for detailed semiquantitative evaluation of their cytologic features. The remaining cases comprised metastatic carcinomas, lymphomas, transitional cell carcinomas, oncocytomas, cortical cysts, and miscellaneous conditions, e.g., abscesses, nonfunctioning kidneys, and hematomas. Overall, the aspiration biopsy determined the nature of the renal mass in 141 cases (93%). False-negative interpretations were due to insufficient diagnostic material in all but one instance. There was one false-positive result.

The role of aspiration biopsy cytology in the diagnosis of pulmonary tuberculosis

The experience at one institution concerning the diagnosis of pulmonary tuberculosis by aspiration biopsy is reviewed. Twelve cases in which acid-fast bacilli were identified in pulmonary aspiration material are reported. The cytologic findings were confirmed by microbiologic culture in nine cases. The advantages of using aspiration biopsy cytology in the diagnosis of pulmonary tuberculosis are discussed. In our experience we conclude that the use of aspiration biopsy cytology in the diagnosis of pulmonary tuberculosis is not only accurate, but also offers several advantages that are important in patient care.

An automated analysis for superoxide dismutase enzyme activity

The pyrogallol autoxidation assay for superoxide dismutase was adapted for analysis by centrifugal analyzer. The precision of the enzymatic assay was estimated using bovine blood superoxide dismutase. Specific activity determined for human erythrocyte superoxide dismutase by the procedure agreed with previously reported determinations. Recovery of bovine blood superoxide dismutase from hemolysates provided a measure of proportional analytic error. Difficulties inherent in attempting to spectrophotometrically assay an enzyme catalyzing a reaction requiring a free radical substrate cannot be eliminated by an automated method. However, the centrifugal analyzer method makes routine enzymatic analysis for superoxide dismutase in numerous samples technically feasible. Moreover, automated analysis can conveniently include a standard such as bovine blood superoxide dismutase when enzyme levels in tissue extracts are assayed. These advantages make the method for assay of superoxide dismutase enzyme activity a useful procedure.

Mediastinal needle biopsy

A review of 52 consecutive needle biopsies of the mediastinum is presented. The aspirated material yielded cytologic and/or histologic diagnosis in 50 needle biopsies; two needle biopsies failed to yield adequate cellular material for diagnosis. All but two of the 50 patients had confirmation of the biopsy diagnosis by surgical, autopsy, or clinical correlation. In 32 patients, a 20-gauge needle was used for the biopsy. A larger-bore (17-gauge) needle with a cutting device was used in 20 cases to obtain more tissue for histologic diagnosis of benign or unusual malignant lesions. Despite the larger size of the needle, the rate of complications remained low.

Enzymatic assembly of slow reacting substance

When basophils or mast cells are stimulated by a specific antigen they release chemical mediators, including a potent bronchoconstrictor, slow reacting substance of anaphylaxis (SRS-A). The structure of SRS from a mouse mastocytoma and rat basophilic leukaemia (RBL-1) cells has been identified as a thioether or arachidonic acid and glutathione [not a thioether of cystene as was originally thought]. SRS has been named leukotriene (LT) C and may be formed by a novel lipoxygenase pathway which also synthesizes 5,6-oxido-7,9,11,14-icosatetraenoic acid (LTA) and 5,12-dihydroxy-6,8,10,14-icosatetraenoic acid (LTB). Homogenates of RBL-1 cells, when incubated with C-arachidonic acid, form 5-hydroxy-icosatetraenoic acid (5-HETE) and 5,12-dihydroxy- and 5,6-dihydroxy-icosatetraenoic acid. The latter is the spontaneous breakdown product of the labile intermediate LTA. Formation of both compounds is stimulated by calcium. We have now produced biologically active SRS in a cell-free system generated from RBL-1 cells. Glutathione was essential for SRS synthesis and calcium stimulated its formation.

Enzymatic formation of prostaglandin D2 by rat basophilic leukemia cells and normal rat mast cells

It has been shown that the major cyclooxygenase product in rat basophilic leukemia (RBL-1) cells and in normal rat mast cells is prostaglandin D2. In RBL-1 cells, prostaglandin D2 is isomerase activity was found in the 150 000 X g microsomal pellet as well as the supernatant fraction. Incubation of RBL-1 microsomes with arachidonic acid without cofactors yielded 17.5 +/- 2% prostaglandin E2 and 9.1 +/- 1.4% prostaglandin D2. The cyclooxygenase activity was enhanced (25%) by epinephrine and the addition of reduced glutathione led to a marked increase in prostaglandin D2 synthesis (3-fold). Incubations with arachidonic acid, glutathione and epinephrine gave the maximum conversion to prostaglandin D2, yielding 7 +/- 0.4% prostaglandin E2 and 35.6 +/- 3.5% prostaglandin D2. Incubations with [14C]prostaglandin H2 to bypass cyclooxygenase confirmed the presence and glutathione dependence of the prostaglandin D2 isomerase in the microsomal fraction and also revealed the presence of the same enzyme in the 150 000 X g supernant. In contrast to RBL-1 cells, incubations of microsomes and supernatant from normal rat mast cells with [14C]-arachidonic acid and [14C]prostaglandin H2 localized the prostaglandin D2 isomerase activity in the soluble fraction. Similar to the enzyme in the RBL-1 cells, the mast cell enzyme was glutathione dependent.

Nucleolar changes in senescing WI-38 cells

Changes in the area, dry mass and morphology of nucleoli were studied during in vitro aging of WI-38 cells. Interferometric methods were used for nucleolar dry mass determinations. The results show that there is (1) an increase in the fraction of cells with one large nucleolus per nucleus, 17% at population doubling 27.3 vs. 93% at population doubling 41.2, (2) an increase in mean nucleolar dry mass (583% at the last doubling), and (3) an increase in mean nucleolar area (236% at the last doubling) with in vitro senescence of WI-38 fibroblast cells. A strong correlation (r = 0.92) between nucleolar dry mass and nucleolar area was demonstrated.

Mutagenicity of some commercially available nitro compounds for Salmonella typhimurium

Benzoyl chloride and 53 commercially available aromatic heterocyclic and aliphatic nitro compounds were tested for mutagenicity in Salmonella typhimurium TA98 and TA100. 34 of 53 nitro compounds (64%) were mutagenic, 4 in TA100 only, 15 in TA98 only, and 15 in both strains. 13 of the heterocyclic derivatives of pyridine, indole, indazole, quinoline, and benzimidazole were mutagenic. 21 of 34 mutagenic nitro compounds were bactericidal. Nitromethane was the only aliphatic tested and was not mutagenic. Benzoyl chloride, a human carcinogen, was mutagenic for TA98.