Biomedical subjects

G Dimopoulos

Publications and source records attributed to G Dimopoulos.

31 records · Page 2Linked to original sources

PubMed1997

Molecular immune responses of the mosquito Anopheles gambiae to bacteria and malaria parasites.

Immune responses of the malaria vector mosquito Anopheles gambiae were monitored systematically by the induced expression of five RNA markers after infection challenge. One newly isolated marker encodes a homologue of the moth Gram-negative bacteria-binding protein (GNBP), and another corresponds to a serine protease-like molecule. Additional previously described markers that respond to immune challenge encode the antimicrobial peptide defensin, a putative galactose lectin, and a putative serine protease. Specificity of the immune responses was indicated by differing temporal patterns of induction of specific markers in bacteria-challenged larvae and adults, and by variations in the effectiveness of different microorganisms and their components for marker induction in an immune-responsive cell line. The markers exhibit spatially distinct patterns of expression in the adult female mosquito. Two of them are highly expressed in different regions of the midgut, one in the anterior and the other in the posterior midgut. Marker induction indicates a significant role of the midgut in insect innate immunity. Immune responses to the penetration of the midgut epithelium by a malaria parasite occur both within the midgut itself and elsewhere in the body, suggesting an immune-related signaling process.

Acute-Phase Proteins↗

PubMed1997

Management of blood pressure instability in severe tetanus: the use of clonidine.

OBJECTIVE: To evaluate the effectiveness of clonidine in the management of unstable blood pressure in severe tetanus. DESIGN: Patients with severe tetanus and blood pressure instability were treated with clonidine and the results were compared with those of other patients with severe tetanus who were not treated with clonidine. SETTING: Intensive care unit of the Chest Hospital of Athens. PATIENTS: We studied 27 patients with severe tetanus and autonomic dysfunction. INTERVENTIONS: Patients were managed according to a protocol. MEASUREMENTS AND RESULTS: Clonidine was administered until blood pressure stability was the fully restored and the dose was then gradually reduced. Five patients from the nonclonidine group and 2 from the clonidine group died. CONCLUSIONS: These results suggest that clonidine is effective in the treatment of blood pressure instability in severe tetanus.

Adrenergic alpha-Agonists↗

PubMed1996

Identification and characterization of differentially expressed cDNAs of the vector mosquito, Anopheles gambiae.

The isolation and study of Anopheles gambiae genes that are differentially expressed in development, notably in tissues associated with the maturation and transmission of the malaria parasite, is important for the elucidation of basic molecular mechanisms underlying vector-parasite interactions. We have used the differential display technique to screen for mRNAs specifically expressed in adult males, females, and midgut tissues of blood-fed and unfed females. We also screened for mRNAs specifically induced upon bacterial infection of larval stage mosquitoes. We have characterized 19 distinct cDNAs, most of which show developmentally regulated expression specificity during the mosquito life cycle. The most interesting are six new sequences that are midgut-specific in the adult, three of which are also modulated by blood-feeding. The gut-specific sequences encode a maltase, a V-ATPase subunit, a GTP binding protein, two different lectins, and a nontrypsin serine protease. The latter sequence is also induced in larvae subjected to bacterial challenge. With the exception of a mitochondrial DNA fragment, the other 18 sequences constitute expressed genomic sequence tags, 4 of which have been mapped cytogenetically.

Amino Acid Sequence↗

PubMed1996

Integrated genetic map of Anopheles gambiae: use of RAPD polymorphisms for genetic, cytogenetic and STS landmarks.

Randomly amplified polymorphic DNA (RAPD) markers have been integrated in the genetic and cytogenetic maps of the malaria vector mosquito, Anopheles gambiae. Fifteen of these markers were mapped by recombination, relative to microsatellite markers that had been mapped previously. Thirty-four gel-purified RAPD bands were cloned and sequenced, generating sequence tagged sites (STSs) that can be used as entry points to the A. gambiae genome. Thirty one of these STSs were localized on nurse cell polytene chromosomes through their unique hybridization signal in in situ hybridization experiments. Five STSs map close to the breakpoints of polymorphic inversions, which are notable features of the Anopheles genome. The usefulness and limitations of this integrated mosquito map are discussed.

Animals↗

PubMed1995

Hydrogen sulfide poisoning: management and complications.

Hydrogen sulfide poisoning is a rare but devastating injury. Four of 8 cases of toxic inhalation of hydrogen sulfide are presented with special attention to the life-threatening complications. Four patients died at the scene of the accident and the remaining 4 had been hospitalized in the Intensive Care Unit (ICU). One patient died in the hospital from cardiogenic pulmonary edema and circulatory failure (pulmonary wedge pressure > 30 mmHg) and 3 patients left the hospital in good health although they presented serious complications. One of them left the hospital with a temporary pacemaker, and 1 of the 2 others died after two months owing to myocardial infarction. The authors discuss in detail the clinical features of this condition and emphasize the need for urgent and appropriate therapy as well as the need for safe environmental conditions.

Acute Disease↗

PubMed1994

Polymorphisms detected by random PCR distinguish between different chromosomal forms of Anopheles gambiae.

We have applied PCR amplification using random primers to distinguish between incipient species of the malaria vector Anopheles gambiae. Individuals belonging to three chromosomally characterized West African forms of this mosquito, which are important epidemiologically as they differ in vectorial capacity, were sampled both from laboratory stocks and from wild populations collected in three localities. The techniques used allowed for the unambiguous classification of the mosquitoes, providing a tool for rapid and efficient diagnosis, which previously relied on cytological examination of polytene chromosomes.

Africa, Western↗

PubMed1994

Analysis of the Anopheles gambiae genome using RAPD markers.

RAPD analysis technique is used as a rapid and reliable tool for genome analysis in the malaria vector Anopheles gambiae. Using more than eighty different commercially available primers we identified more than sixty different DNA segments that were differentially amplified in different strains of An. gambiae s.s. and An. arabiensis. An estimate of the cytogenetic position of these markers is provided by their hybridization to divisional dot-blot filters. Potentially useful RAPD markers can be cytogenetically mapped with more precision by in situ hybridization and, as they segregate as dominant markers in a Mendelian fashion, they can also be genetically mapped relative to other genes or rearrangements. Finally, we identified markers for their potential use in the identification of different mosquito strains.

Animals↗

PubMed1977

Tests for completeness of vagotomy.

A battery of tests was applied to 60 patients at periods varying from 2 to 24 months after they had undergone truncal vagotomy (42 with pyloroplasty, 18 with gastro-enterostomy). The major comparison was between those with endoscopic evidence of recurrent duodenal ulcers, and those in whom endoscopy showed no abnormality. Tests which differentiated between the two groups to a statistically significant extent were those for increased acid concentration in the first hour after insulin and serum gastrin, which was lower in this group. Useful, but statistically not significant tests, in patients with no endoscopic evidence of recurrent ulcers, were a postoperative decrease in basal acid output and maximal acid output after pentagastrin or insulin. Symptoms, the combined pentagastrin-insulin test, the volume of acid secreted after insulin, and the acid concentration in the second hour after insulin stimulation were poor indicators for differentiating between patients with recurrent ulcers and those without ulcers. Almost as much information was obtained by the postoperative basal acid output alone as by the pentagastrin and insulin stimulatory tests.

Duodenal Ulcer↗

PubMed1977

The effect of vagotomy on the lower oesophageal sphincter: a manometric study.

The pressure profile of the gastro-oesophageal junctional zone was studied at rest and during abdominal compression in 26 duodenal ulcer patients after subdiaphragmatic truncal vagotomy with a drainage procedure. An 'early' group of 9 patients was investigated 10-14 days after surgery and a 'late' group of 17 patients more than 1 year after operation. Comparisons were made with 25 control subjects. The resting lower oesophageal sphincter pressures after vagotomy in both the early and late groups were similar to the levels of sphincter pressure in the controls. However, the increase in sphincter pressure always observed during absominal compression in normal subjects was significantly decreased by complete vagotomy, and the normal increase in the gastrosphincteric pressure gradient was not produced. All 26 patients were tested for completeness of vagotomy using the insulin/pentagastrin test. In 19 patients the vagotomy was complete and in 7 patients it was judged to be incomplete. A decrease in the gastro-sphincteric pressure gradient on manometric study of the lower oesophageal sphincter was interpreted as indicating complete vagotomy. Accurate correlation between secretory response and compression response was achieved in all patients with complete vagotomy and in 5 of the 7 patients with incomplete vagotomy.

Duodenal Ulcer↗

PubMed1975