Quantification of dissolved organic carbon at very low levels in natural ice samples by a UV-induced oxidation method

The study of chemical impurities trapped in solid precipitation and accumulated in polar ice sheets and high-elevation, midlatitude cold glaciers over the last several hundreds of years provides a unique way to reconstruct our changing atmosphere from the preindustrial era to the present day. Numerous ice core studies of inorganic species have already evaluated the effects of growing anthropogenic emissions of SO(2) or NO(x) on the chemical composition of the atmosphere in various regions of the world. While it was recently shown that organic species dominate the atmospheric aerosol mass, the contribution of anthropogenic emissions to their budget remains poorly understood. The study of organics in ice is at the infancy stage, and it still is difficult to draw a consistent picture of the organic content of polar ice from sparse available data. A UV oxidation method and IR quantification of CO(2) was optimized to obtain measurements of dissolved organic carbon content as low as a few ppbC. Stringent working conditions were defined to prevent contamination during the cleaning of ice. Measurements in various ice cores corresponding to preindustrial times revealed dissolved organic carbon content of less than 10 ppbC in Antarctica and up to 75 ppbC in alpine ice.

Single-Locus Inheritance in the Tetraploid Treefrog Hyla versicolor with an Analysis of Expected Progeny Ratios in Tetraploid Organisms

The recently evolved autotetraploid frog, Hyla versicolor , was examined electrophoretically for evidence of genomic restructuring leading to diploidization. Loci were tested against the progeny ratios expected if inheritance was disomic vs. tetrasomic. Two loci (Mpi and Sod-2) appeared to be inherited tetrasomically, one (Mdh-2) appeared to be inherited disomically, and one (Tpi) appeared to be inherited disomically in one family and tetrasomically in another family, when tested conventionally against 1:2:1 and 1:4:1 segregation ratios. The minimum number of progeny required for this type of analysis for codominant alleles is shown to be 92. Progeny resulting from double reduction were observed, and the occurrence of a null allele class at Mpi was noted. A reexamination of expected progeny ratios in tetraploid organisms reveals that tetrasomic inheritance patterns cannot be predicted without adequate knowledge of the amount of crossing-over, the proportion of tetravalents vs. random bivalents that are formed, and the ratio and types of centromere segregation (alternate and adjacent) that occur from tetravalents in the species being studied. However, disomic inheritance can be unambiguously confirmed only by the production of all heteroallelic gametes from homobivalent, symmetrically heterozygous individuals. In addition, a method is described for estimating genecentromere distances using the ratio of progeny genotypes in certain crosses in tetraploid species.

Endobronchial stent placement for the management of airway complications after lung transplantation

PURPOSE

To retrospectively evaluate the efficacy and complications of endobronchial stent placement for the management of airway complications following lung transplant.

MATERIALS AND METHODS

From 1992 to 2003, tracheobronchial stenting was performed on 25 lung transplant recipients (16 male and 9 female; mean age 51.6 years; range 21-65 years). A total of 27 lesions were treated and 27 stents were deployed (nine bronchomalacia, 12 bronchial stenosis, three bronchial stenosis and bronchomalacia both and three anastomotic dehiscence). The clinical and bronchoscopic follow-up ranged from 1 month to 69 months.

RESULTS

The technical success was 100%. Eighty-four percent of patients had immediate relief in dyspnea. The overall complication rate following stent placement was 0.049 per patient per month (23 complications/471 patient months). Stent migration and granulation tissue formation were the most frequent complications. The mean percentage change in FEV-1 was significantly greater than zero at 1 month and 6 months (P<.05) post-stent placement. The mean percentage change in FEV-1 was marginally greater than zero at 12 months (P=.07).The mean percentage change in FVC was marginally greater than zero at 1 month and 6 months (P=.08) post-stent. It was not significantly greater than zero at 12 months (P=1.00).

CONCLUSION

Tracheobronchial stent placement provides effective palliation of postoperative airway complications in lung transplant with morbidity that can be managed effectively by available treatment options. Airway stenting may be used as a primary management option for airway complications after lung transplantation as a large number of patients are not suitable candidates for repeat surgery.

Long-term response of primary biliary cirrhosis (stage I) to therapy with ursodeoxycholic acid

We report about a 56-year-old asymptomatic female patient, who was examined in April 1991 for an increase of biochemical parameters of the liver. Based on the biochemical and serological results (abnormal cholestatic liver function tests, positive antimitochondrial antibodies) as well as liver biopsy primary biliary cirrhosis stage I was diagnosed. Therapy with ursodeoxycholic acid (12mg/kg body-weight/die) was started. Follow-up examinations indicated that cholestatic parameters had normalized and antimitochondrial antibodies became negative. In a further biopsy of the liver nearly regular liver parenchyma was demonstrated. Thus, therapy with ursodeoxycholic acid was stopped. However, in November 1992 cholestatic parameters increased again and, antimitochondrial antibodies recurred (subtype anti-M9: positive) without any clinical symptoms. Ursodeoxycholic acid therapy was reintroduced again. Within 3 months cholestatic parameters returned to normal and antimitochondrial antibodies were eliminated again. Since then ursodeoxycholic acid has been given continuously and a long-term remission as defined by clinical, serological and histological criteria could be maintained until today. This case report indicates a serological remission and a marked histological improvement in a female patient with an early stage of primary biliary cirrhosis (stage I) during therapy under ursodeoxycholic acid. It has to be discussed whether certain early stages of primary biliary cirrhosis with benign antimitochondrial antibody-profile (anti-M9: positive) respond well to long-term treatment with ursodeoxycholic acid.

Genetic Evidence for Hybridization of Pallid and Shovelnose Sturgeon

To determine the genetic origin of individual sturgeon that are morphologically intermediate to pallid (Scaphirhynchus albus) and shovelnose (Scaphirhynchus platorhynchus) sturgeon, we combined previously published mitochondrial DNA (mtDNA) and microsatellite data with additional microsatellite data. Two sympatric populations of pallid and shovelnose sturgeon from the upper Missouri River and a sympatric population containing pallid, shovelnose, and putative pallid-shovelnose hybrids from the Atchafalaya River were analyzed using an index of hybridization and a principle components analysis of individual relatedness scores. The addition of new microsatellite data improved our ability to genetically differentiate individual pallid and shovelnose sturgeon collected in both areas. Our methods distinguished morphologically intermediate Atchafalaya River sturgeon, which appear to be genetically intermediate between pallid and shovelnose sturgeon. The results support a hybrid origin for morphologically intermediate individuals, although it is unclear whether they are all first-generation hybrids or if some are the result of subsequent backcrossing with the more common shovelnose sturgeon.

Differential Effects of Long-Term Treatment with Clozapine or Haloperidol on GABA Transporter Expression

BACKGROUND

Post-mortem studies with brain samples of schizophrenic patients led revealed altered GABA-ergic markers like reduced expression of the GABA transporter GAT-1. Whether this effect is due to the pathophysiology of schizophrenia or to antipsychotic treatment has not been investigated. We therefore established an animal trial of long-term antipsychotic treatment to address this question.

METHODS

A total of 33 adult male rats were investigated in three cohorts of 11 animals. One group received clozapine (45 mg/kg/ day), another group haloperidol (1.5 mg/kg/day), and the third one pH-adapted water over a period of 6 months. In situ hybridization with cRNA probes specific for GABA transporters VGAT, GAT-1 and GAT-3 were performed in comparison to control animals.

RESULTS

While GAT-1 was upregulated, VGAT expression declined in cortical and limbic brain regions, whereby haloperidol showed a greater effect than clozapine. GAT-3 expression was suppressed in parietal and temporal cortex.

CONCLUSIONS

We thus conclude that long-term antipsychotic treatment alters GABA transporter expression in rat. The upregulation of GAT-1 contrasts with the post-mortem finding of reduced GAT-1 expression in schizophrenic patients. Our results facilitate the distinction between disease dependent changes of GABAergic markers and medication effects.

Effects of chronic haloperidol and clozapine treatment on AMPA and kainate receptor binding in rat brain

BACKGROUND

Alterations in AMPA and kainate receptor binding have been revealed in post-mortem schizophrenic brains. As most patients had been treated with antipsychotics, medication effects cannot be excluded as a possible explanation for these results.

METHODS

Within the framework of this animal study, we investigated [3H]AMPA and [3H]kainate receptor binding in different rat brain regions following 6 months of oral treatment with either haloperidol (1.5 mg/kg/day) or clozapine (45 mg/kg/day).

RESULTS

AMPA receptor binding was increased after haloperidol treatment in the striatum, nucleus accumbens, cingulate cortex, and insular cortex. Clozapine showed increased AMPA receptor binding only in the anterior cingulate cortex. Kainate receptor binding was increased by both drugs in all hippocampal subfields.

CONCLUSIONS

This altered receptor binding may be related to beneficial neuroleptic effects and side effects. Furthermore, neuroleptic therapy may contribute to some of the post-mortem findings in the striatum in schizophrenia.

Die Wirkung von Antipsychotika auf glutamaterge Neurotransmission im Tiermodell

Post-mortem investigations have confirmed that glutamatergic NMDA, AMPA, and kainate receptors are involved in the pathophysiology of schizophrenia. It is still unclear, however, whether the altered number of receptors is caused by the disease itself or the medication. Therefore, animal models were investigated for effects of antipsychotic medication after treatment periods of up to 6 months, the results of which are summarized here. Generally, NMDA receptor binding was found to be increased in striatum and nucleus accumbens after therapy with haloperidol, whereas clozapine only increased the number of receptors in nucleus accumbens. While haloperidol led to an increase in AMPA receptors in the posterior cingulate gyrus, striatum, insular cortex, and n. accumbens, clozapine was found to elevate ligand binding in the anterior cingulate gyrus and infralimbic cortex. Although kainate receptor binding was increased in hippocampus by both antipsychotics, clozapine was significantly more effective. In conclusion, data reveal different effects from the typical neuroleptic haloperidol and the atypical antipsychotic clozapine. The results suggest that post-mortem findings in patients with schizophrenia may at least partially be explained by drug effects and plasticity changes induced by long-term medication with antipsychotics.

Tuberculous involvement of the oesophagus with oesophagobroncheal fistula

Tuberculous involvement of the oesophagus is a rare disease. Even if it is suspected, diagnosis is often difficult though dysphagia and chest pain are the most common symptoms without any other specific signs of tuberculosis. The diagnosis is based on oesophagography, oesophagoscopy, bronchoscopy, and computed tomographic scan. Suspected tuberculosis can be confirmed with histology, smear, and culture. The two most common differential diagnoses are Crohn's disease and carcinoma. The case is reported of a female patient with tuberculous involvement of the oesophagus, who developed an oesophagobroncheal fistula during steroid treatment started for suspicion of Crohn's disease. The patient was immunocompromised due to treatment with azathioprine that she was receiving for multiple sclerosis. The fistula was successfully treated by antituberculous chemotherapy alone.

Search for the scalar top quark in pp collisions at square root[s] = 1.8 TeV

We have performed a search for scalar top quark (stop) pair production in the inclusive electron-muon-missing transverse energy final state, using a sample of pp events corresponding to 108.3 pb(-1) of data collected with the D0 detector at Fermilab. The search is done in the framework of the minimal supersymmetric standard model assuming that the sneutrino is the lightest supersymmetric particle. For the dominant decays of the lightest stop, t-->b chi+1 and t-->blnu, no evidence for signal is found. We derive cross-section limits as a function of stop ( t ), chargino ( chi+1), and sneutrino ( nu) masses.

Direct search for charged higgs bosons in decays of top quarks

We present a search for charged Higgs bosons in decays of pair-produced top quarks in pp collisions at sqrt[s] = 1.8 TeV recorded by the D0 detector at the Fermilab Tevatron collider. With no evidence for signal, we exclude most regions of the ( M(H+/-),tan(beta)) parameter space where the decay t--> H(+)b has a branching fraction >0.36 and B(H+/--->tau(nu)(tau)) is large.