Biomedical subjects

T Adrian

Publications and source records attributed to T Adrian.

At least 19 recordsLinked to original sources

PubMed2000

A novel high-pressure liquid-liquid extraction process for downstream processing in biotechnology: extraction of cardiac glycosides.

This investigation examines phase equilibrium phenomena that can be used to create two water-like solvents for liquid-liquid extraction in downstream processing in biotechnology: a completely miscible, binary liquid mixture of water and a hydrophilic organic solvent (e. g., an alcohol) reveals a liquid phase split, when it is pressurized with a "near-critical" gas (i.e., a substance which at ambient conditions is a gas, near its critical temperature). This phase split results in two hydrophilic liquid phases. Making use of this phenomenon in process development first requires research on the phase split phenomenon and, second, research on the feasibility of biomolecule extraction and separation. In this study, basic fluid phase equilibrium phenomena are briefly described. Then, experimental results are reported for the partitioning of small amounts of cardiac glycosides (digitoxin and digoxin) on coexisting liquid phases in the high-pressure, three-phase, vapor-liquid-liquid equilibrium of the ternary system of "near critical" CO(2) + water + 1-propanol, at 313 K and 333 K. Finally, a process for extraction and separation of the aforementioned glycosides by means of the high-pressure phase equilibrium phenomenon is discussed.

1-Propanol↗

PubMed1999

Multiplex polymerase chain reaction for subgenus-specific detection of human adenoviruses in clinical samples.

The polymerase chain reaction (PCR) has been used previously for the detection and typing of adenoviruses directly in clinical samples. Since under clinical conditions subgenus-specific identification is often sufficient, we extended the genus- and type-specific PCR by a subgenus-specific PCR. By sequencing several loop I4 gene regions of the hexon (major adenovirus coat protein) and comparing them to published sequences, subgenus-specific sequences were identified in this region. By using primers targeted to this region and to a conserved hexon gene region, a multiplex, nonnested PCR for the detection and subgenus-specific identification of adenoviruses could be established. The six subgenus-specific amplimers are distinguishable by agarose gel electrophoresis, and subsequent restriction analysis is not necessary. The specificity of the subgenus-specific primer pairs was tested on 23 adenovirus prototypes, representing all six subgenera, on 9 subgenus B and D intermediate strains, and on 16 subgenus C genome types. Furthermore, multiplex, subgenus-specific PCR was performed directly with 100 clinical specimens, including stool samples, ocular swabs, and throat swabs. Adenoviruses of all subgenera could be detected. Especially for clinical application, the rapid, one-step differentiation between subgenus D adenoviruses, causing the severe and highly contagious epidemic keratoconjunctivitis, and subgenus B and E adenoviruses, causing relative harmless ocular infections, is of great importance. The subgenus-specific PCR could also facilitate the primary classification of unknown virus isolates.

Adenovirus Infections, Human↗

PubMed1997

Cholecystokinin modulates mucosal immunoglobulin A function.

BACKGROUND: We have established that mucosal immunoglobulin A (IgA) production is highly dependent on cholecystokinin release and is markedly suppressed by glucocorticoids. The purpose of the present study was to examine the role of cholecystokinin on the functional responsiveness of the mucosal IgA system in glucocorticoid treated rats. METHODS: A total of 24 Fischer rats were assigned to three groups of 8 animals each. Animals were injected with vehicle (CON), dexamethasone (DEX) (0.08 mg/150 g), or DEX (0.08 mg/150 gm) and ARL1294KF (500 ng twice daily), a novel and potent long-acting cholecystokinin agonist (DEX+CCK). Animals were treated for 48 hours and killed. Duodenum was harvested, and the total mucosal concentration of cholecystokinin was measured by radioimmunoassay. Mucosal IgA was assayed by quantitation of immunoreactive cells in the ileum. Bacterial adherence was evaluated by quantitative culture of vigorously washed stripped cecal mucosa. Transepithelial electrical resistance, a measure of tight junction permeability, was assessed by mounting strips of adjacent cecal mucosa in Ussing chambers. RESULTS: Glucocorticoid administration resulted in a statistically significant (p < 0.001) decrease in duodenal cholecystokinin, decreased IgA, and impaired mucosal immunity (increased bacterial adherence and decreased tissue resistance). Cholecystokinin administration preserved mucosal immune function in DEX-treated rats. CONCLUSIONS: Cholecystokinin may play an important role in maintaining the functional responsiveness of mucosal immunity during catabolic stress.

Animals↗

PubMed1996

Detection and significance of adenoviruses in cases of sudden infant death.

Respiratory tract infections have been thought to act as a trigger mechanism in sudden infant death. In 118 autopsy cases of infant death, paraffin-embedded or frozen lung tissues were investigated by means of a nested polymerase chain reaction (PCR) to detect adenovirus (AV) DNA. The primers used are general primers and allow the detection of most pathogenic adenoviruses with high specificity and sensitivity and independently of devitalization of viruses or degradation of viral DNA. For the investigation three groups were established: there were 13 cases of unnatural death, 78 cases of natural death without histological signs of interstitial pneumonia, and 27 cases with interstitial pneumonia. The first group was AV negative. In the group without interstitial pneumonia AV was detected in 10.2% of the cases. In the group with interstitial pneumonia the frequency of AV detection was almost 26%. The results obtained demonstrate an association between interstitial pneumonia and detection of AV DNA, indicating that AV may play an important part in pulmonary infection in infants. Histological evidence of interstitial pneumonia was not observed in all AV-positive cases, perhaps because nonspecific virus-related changes occurred only in early stages of viral infection. Comparison of the AV frequency in SIDS (25%) and non-SIDS cases (4%) indicates an association between pulmonary AV infections and sudden death. These results support the working hypothesis of respiratory infections acting as a trigger mechanism in sudden infant death.

Adenoviridae↗

PubMed1996

Genome polymorphism of human adenoviruses of subgenus C.

The genome of adenovirus (AV) types 1, 2, and 5 is known to be very variable as evidenced by the great number of genome types described (36, 61, and 35 for AV1, 2, and 5 respectively). Physical maps were constructed for nearly all of the restriction or R-variants by biochemical methods and by adapting restriction fragments of defined molecular weight. The alterations found with seven DNA restriction endonucleases were mapped on the genome. Altered restriction sites, found for the genome types of each of the three serotypes, appeared to be randomly distributed over the genome, although mutations seemed to occur preferentially on distinct sites of the genome. Many strains, especially those of AV5, were genomically much more related with one another than with the prototype. This finding is compatible with the interpretation that the related strains were derived from an unknown common ancestor.

Adenoviruses, Human↗

PubMed1995

Immunological adenovirus variant strains of subgenus D: comparison of the hexon and fiber sequences.

The fiber and hexon genes of the immunological adenovirus (Ad) variant strains Ad9/Hx and Ad15/Hx, belonging to subgenus D, were sequenced and compared to the corresponding sequences of the prototypes Ad9 and Ad15. It was found that the variants possessed a novel and identical hemagglutinin as they could not be distinguished by hemagglutination-inhibition tests. These serological data were now confirmed on DNA and protein level. The analyzed hexon regions of Ad15 and Ad15/Hx, and Ad9 and Ad9/Hx, respectively, were 100% identical on the amino acid level. The comparison between the variant fibers revealed that they possessed an identical fiber, which was distinct from the Ad9 and Ad15 fiber polypeptides. It seems likely that the donor of the novel fiber protein was a so far unidentified subgroup D adenovirus. The fiber polypeptides of Ad9 and the variants revealed the highest homology (73.7%), whereas the variants and the Ad15 fiber had only 64.2% of the amino acids in common. Most of the differences between the adenovirus serotypes were detected in the fiber knob. Seven conserved sequences found for subgenus D fibers could be confirmed for the fibers of the variants. Furthermore, the data presented complement the knowledge on the organization of subgenus D fiber genes.

Adenoviruses, Human↗

PubMed1995

Sequence characterization and comparison of human adenovirus subgenus B and E hexons.

The hexon genes of human adenovirus (AV) types 3, 16 (both subgenus B), and 4 (subgenus E) were sequenced and the nucleotide and predicted amino acid sequences were compared. We observed a high degree of homology between the three serotypes and thus could confirm the close evolutionary relationship of subgenera B and E which was previously inferred after comparing other genome regions. Employing the three-dimensional model of the AV2 hexon, the structures of the three hexons were predicted. The major differences between the hexons of AV3/AV16 and AV3/AV4 were confined to the I1 and I2 surface loops. As expected from cross-reactions in neutralization, the hexons of AV16 and AV4 were not only very homologous in the conserved regions but also in the loops I1 and I2. This indicates that the type-specific antigenic determinant is located in these regions of the hexon. Closer examination of the loop I4 sequences, including also serotypes of subgenera A, C, and F, revealed that this region is subgenus-specific. The finding that AV4 differs from AV3 and AV16 in loop 1(4) supports the placement of AV4 in a separate subgenus.

Adenoviruses, Human↗

PubMed1995

Characterization of adenovirus subgenus D fiber genes.

The fiber genes of human adenovirus types 8, 9, 15, and two genome types of intermediate adenovirus 15/H9, all belonging to subgenus D, were sequenced and the nucleotide and predicted amino acid sequences compared. The analyzed peptide sequences were consistent with the structural domains described for other adenoviruses: an amino-terminal tail region, an intervening shaft region composed of eight repeating 15-amino-acid segments, and a carboxy-terminal knob. Furthermore, several highly conserved sequences could be confirmed. The fiber genes of AV9 and the AV15/H9 intermediate strains were 100% identical, not only in the coding region, but also in the presented 5'- and 3'-flanking regions. These findings support the hypothesis that intermediate strains arise by recombination of two serologically different parent viruses. The predicted AV8, AV9, and AV15/H9 polypeptides showed an overall homology of 92%. In the knob regions, AV8 and AV9; AV15/H9 intermediate strains revealed nine mismatches. AV8 is the main causative agent of epidemic keratoconjunctivitis in man, whereas AV9 and the AV15/H9 intermediate strains only infrequently cause acute follicular conjunctivitis. Since the knob is the component responsible for interaction with the cell receptor, these differences in the receptor binding sites should be expected to play an important role in the differences in pathogenicity.

Adenoviruses, Human↗

PubMed1994

Determination of the size of HIV using adenovirus type 2 as an internal length marker.

The size of a virion is a key criterion to its proper classification and may have implications in many practical aspects. Size determinations by thin section electron microscopy often result in length aberrations of more than 10% because of a number of preparative and instrumental inaccuracies, e.g. specimen shrinkage or swelling and unreliable calibration. Using adenovirus type 2 as an isometric size marker for internal calibration, we have determined the diameters of mature and immature HIV-1 to be 110 to 128 and 132 to 146 nm, respectively. The marker had been used either as a purified particle suspension added to the HIV producing culture, or adenovirus had been propagated together with HIV by infecting HIV producing cells. Using well characterized isometric markers, e.g. an icosahedral virus, in thin section electron microscopy appears to be a suitable technique for viral size determinations.

Adenoviruses, Human↗

PubMed1994

Altered antroduodenal motility after cholecystectomy.

BACKGROUND: Persistent nonspecific symptoms such as epigastric pain, bloating, nausea, and bilious vomiting are common following cholecystectomy. The etiology of these symptoms is unknown, but abnormal antroduodenal motility associated with duodenogastric reflux (DGR) is a possible cause. PATIENTS AND METHODS: Sixteen postcholecystectomy patients and 19 healthy volunteers ("normals") were studied. Ten of the patients were asymptomatic and 6 were symptomatic. The study consisted of a 4-hour 99mTc-DISIDA (diisopropyl imidodiacetic acid) infusion and gastric aspiration, 24-hour intragastric pH monitoring, and 24-hour ambulatory antroduodenal manometry. RESULTS: The postcholecystectomy patients showed increased DGR of the infused 99mTc-DISIDA. The data are given as coulter counts x 10(6)/min. The increase was more marked in symptomatic postcholecystectomy patients (2.54 +/- 0.15) compared to asymptomatic patients (1.21 +/- 0.46) or normals (0.26 +/- 0.15). Postcholecystectomy patients had increased percentage of time with intragastric pH > 3. In the supine period in particular, the pH was > 3 in symptomatic patients 25.4% +/- 7.7% of the time versus 8.1% +/- 4.3% for asymptomatic patients (P < 0.01). The antral phase III frequency after cholecystectomy was 2.5 +/- 0.09 cycles/min compared to 3.2 +/- 0.08 cycles/min in normals (P < 0.0001). Furthermore, propagation of the phase III front in the duodenum was significantly slowed to 0.14 +/- 0.02 cm/s after cholecystectomy compared to 0.27 +/- 0.02 cm/s in normals (P < 0.001). The duration of phase III in the proximal duodenum after cholecystectomy was also decreased to 4.3 +/- 0.27 min compared to 5.9 +/- 0.35 min in normals (P < 0.005). CONCLUSIONS: Fasting antroduodenal motility is altered after cholecystectomy. The abnormality is associated with increased DGR, which is more marked in symptomatic patients.

Adult↗

PubMed1993

Adenovirus isolations from patients with conjunctivitis in Thuringia.

57 adenoviruses (AV's) isolated from 1979 through 1986 from about 200 patients with (kerato) conjunctivitis were identified as AV8, 7, 3, 17/H29, 9, 2, and 10, in decreasing order. DNA restriction analysis with 5 enzymes revealed the three strains of the intermediate 17/H29 strains to be identical. The same conclusion was reached for the two AV9 strains, but the latter differed from the AV9 prototype in two enzymes. Restriction site alterations were physically mapped for 3 enzymes and for an AV8 variant differing in HindIII.

Adenovirus Infections, Human↗

PubMed1992

Genome type analysis of adenovirus type 4.

Twenty AV4 isolates were analysed with 18 restriction endonucleases. They could be classified into two genome types (genomic clusters) AV4p and AV4a. Combined with data from Li and Wadell [Arch Virol 1988;101:65-77], DNA variants p1-p8 and al-a3 were defined. The genetic relatedness within the genome types was in the range of 88-99% comigrating fragments, whereas < 62% of the fragments were comigrating between the genome types.

Adenoviruses, Human↗

PubMed1991

A selective loss of somatostatin in the hippocampus of patients with temporal lobe epilepsy.

Although neuropeptides have been demonstrated to be hippocampal neuromodulators in laboratory animals, their role in human hippocampal physiology or pathophysiology remains to be defined. The concentrations of somatostatin, cholecystokinin octapeptide, vasoactive intestinal polypeptide, and dynorphin A 1-17 were determined in hippocampal tissue resected from patients with cryptogenic temporal lobe epilepsy, a common seizure disorder originating in or near the hippocampus. Control tissue was obtained from cadavera or epilepsy patients in whom the hippocampus was removed during the resection of temporal lobe tumors. Peptide determinations were performed on extracts of punch biopsy specimens taken from six different hippocampal regions. A significant decrease in immunoreactive somatostatin concentration was identified in the dentate gyrus and in region cornu ammonis 4 of cryptogenic temporal lobe epilepsy specimens. No significant changes were present in any other hippocampal region or in the levels of other peptides. In situ hybridization studies performed on cryostat sections from similar patients confirmed a marked loss of neurons expressing the somatostatin gene, which was restricted to the dentate hilus. The density of specific 125I-somatostatin binding to cryostat sections, as determined by semiquantitative in vitro autoradiography, was significantly increased in the dentate gyrus of the cryptogenic epilepsy patients, compared with tumor control specimens. We conclude that a loss of somatostatin-producing interneurons with an upregulation of dentate somatostatin receptors is a specific and characteristic element in the pathophysiology of human cryptogenic temporal lobe epilepsy.

Adolescent↗

PubMed1991

Restriction site mapping of subgenus D adenoviruses, prototypes 42-47, intermediate and atypical strains.

Restriction site maps with the endonucleases BamHI, BgIII, and HindIII were elaborated for 19 adenovirus strains of subgenus D, namely candidates AV42 to 47, 6 intermediate and 7 atypical strains. On the basis of several types mapped by biochemical methods, the physical maps for the 19 strains were constructed by adapting restriction fragments of defined molecular weight to the known maps, as the homology among strains within this subgenus is considerable. Other prototypes mapped by adaptation were also used for reference. The localization of the restriction sites on the genome was analyzed for all mapped types or strains of subgenus D (except AV8). The sites appeared to be randomly distributed; only one site was common to all strains.

Adenoviruses, Human↗

PubMed1990

Restriction site mapping of adenovirus prototypes of subgenus D.

Restriction site maps with the endonucleases HindIII, BglII, and Bam HI were elaborated for the majority of 23 adenovirus prototypes of subgenus D (AV8 to AV39). On the basis of four or five types which have been mapped by biochemical methods, the physical maps for other types were constructed by adapting restriction fragments of defined molecular weight, as the homology among types of the same subgenus is considerable. Prototypes of subgenus D shared several common restriction sites; different sites, however, were distributed at random over the genome. The gene loci for hexon and fiber did not show either higher or lower variability.

Adenoviridae↗

PubMed1990

Genome type analysis of 480 isolates of adenovirus types 1, 2, and 5.

Adenovirus (AV) types 1, 2, and 5, isolated from about 480 patients from 1960 to 1985, most from the United States and Central Europe, were studied by DNA restriction analysis with the endonucleases BamHI, BglII, BstEII, EcoRI, HindIII, KpnI, and SmaI and compared with the respective prototypes. All different fragment patterns are presented as schematic drawings and their distribution on the genome types was analyzed. Prototype-like strains were isolated in all three types. AV2 exceeded AV1 and AV5 in its genetic variability. Among the many genome types found (36, 61, and 35 for AV1, 2, and 5 respectively), only one or few of each type prevailed, whereas many others were found only once. The temporal and geographic distribution of the genome types is presented.

Adenoviruses, Human↗

PubMed1989

Intermediate adenovirus strains of subgenus D occur in extensive variety.

Eight intermediate adenovirus strains of seven serotypes, some of them related in their neutralizing or hemagglutinating antigens to new candidate serotypes, are presented in their serological properties and DNA fragment patterns with four endonucleases (BglII, BstEII, HindIII, SmaI). For characterization and strain comparison, an intensive serological identification is more meaningful than DNA restriction analysis. The intermediate strains were related in neutralization to types 28, 33, 37, 38, 44, or 46, in hemagglutination-inhibition to types 9, 13, 30, 45, or the hemagglutinin variant Hy.

Adenoviridae↗

PubMed1989

Molecular epidemiology and restriction site mapping of adenovirus 7 genome types.

From the United States, the Federal Republic of Germany, and other regions, 168 strains of AV7, isolated between 1961 and 1985, were analyzed by six restriction endonucleases and nine genome types were identified. The enzymes BamHI and HindIII were most discriminative. The genome type D5 (or 7b) predominated with 120 isolates since 1970 in both countries. Strains of D2 (7a) and D4 (7c) were isolated for a limited time, D3 for an extended time period. Several clusters of infections with the same genome type were found. Differences in pathogenicity could not be derived from our data. On the basis of restriction site mapping, most other genome types were similar to D5, one to D2 and one to the prototype (D1). The genomic relation between AV7 and AV3 is discussed and shown by a dendrogram.

Adenoviridae↗