Search PubMed⌕ Search

Biomedical subjects

C Diaconu

Publications and source records attributed to C Diaconu.

42 records · Page 3Linked to original sources
PubMedDate not supplied

Studies on the intermolecular forces involved in the antibody-antigen interactions, using V3 synthetic peptides and sera from HIV1 seropositive patients.

The nature of physical forces responsible for the antibody-antigen (Ab-Ag) reaction was analyzed in an original system, represented by synthetic peptides derived from the V3 consensus sequences of some HIV1 subtypes gp 120 and HIV1 positive human serum. For locating antigenic determines, flexibility, hydrophilicity and hydrophobicity profiles of the V3 peptides were analysed. The hydrophilicity indicates that V3 apex borders are involved in the first stage of the reaction. The flexibility and hydrophobicity suggest that the apex of the V3 loop (GPGR/Q) is involved in the stabilization of the complex by hydrophobic interactions. Further, we followed up the influence of the dielectric constant and of the pH upon the forces established between Ab and Ag. Modifications in the dielectric constant and pH reveal a significant contribution of electrostatic and van der Waals forces in securing the intermolecular complementarity. D2O produces the highest augmentation of the antibody affinity for the most hydrophilic peptides, while a very slight one was recorded for the most hydrophobic sequence. A high affinity of antibodies for the peptides MN, R and Z was registered at an acid pH, when their His residue was protonated. On the contrary, no influence was recorded in the case of the peptide A, which does not contain any His residue.

Amino Acid Sequence↗
PubMedDate not supplied

[The action of amphiphilic drugs on human fibroblasts in vitro. Their possible use in antiviral and antitumor chemotherapy].

The LDH cytotoxicity test is able to emphasize the stabilisation of human embryo fibroblast membranes, in vitro, by two amphiphilic drugs: the metomidate and the thymolol. The membrane stabilisation is emphasized by the reduced LDH externalization as compared with the untreated cells. The use of the LDH test for the selection of some natural complexes or synthetic drugs with membrane stabilising and potential antiviral activity is proposed. The inhibition of LDH by metomidate was recorded, as decreasing of the enzyme activity with increasing metomidate concentration. This fact explains the known lactic acid accumulation, under metomidate treatment of human subjects. The use of metomidate in classical cancer treatment potentiation is proposed instead of lactate externalization inhibitors, already used for this aim.

Antineoplastic Agents↗
PubMedDate not supplied

[Nonocclusive intestinal ischemia].

Acute or chronic intestinal ischaemia can be the consequence of either intrinsic vascular disease, systemic disease, drugs or surgical procedures. In one quarter of the patients with intestinal ischaemia, no major vascular obstructions can be detected. Very rarely, the cause of ischaemia is splanchnic vasoconstriction due to cardiac arrhythmias or sepsis. The bowel becomes ischaemic as a result of underperfusion. The clinical picture resembles the one of occlusive intestinal ischaemia. From the pathological standpoint, the ischaemia is more intense on the antimesenteric border of the bowel an the lesions are more advanced in the mucosal than in the serosal layer. Often, the ischaemia involves other organs too: liver, spleen or gallbladder. The reconstructive vascular procedures are inefficient, the only therapeutical options remains the resection of the infarcted bowel, together with other organs involved in the ischaemia process. The mortality rate approaches 90%.

Adult↗
PubMedDate not supplied

[Nonobstructive intestinal ischemia].

Acute or chronic intestinal ischaemia can be the consequence of either intrinsic vascular disease, systemic disease, drugs or surgical procedures. In one quarter of the patients with intestinal ischemia, no major vascular obstructions can be detected. Very rarely, the cause of ischaemia is splanchnic vasoconstriction due to cardiac arrhythmias or sepsis. The bowel becomes ischaemic as a result of underperfusion. The clinical picture resembles the one of occlusive intestinal ischaemia. From the pathological standpoint, the ischaemia is more intense on the antimesenteric border of the bowel and the lesions are more advanced in the mucosal than in the serosal layer. Often, the ischaemia involves other organs too: liver, spleen or gallbladder. The reconstructive vascular procedures are inefficient, the only therapeutical options remains the resection of the infarcted bowel, together with other organs involved in the ischaemic process. The mortality rate approaches 90%.

Adult↗
PubMedDate not supplied

Flow-cytometry DNA index of colorectal carcinomas.

The authors investigated the relationship between flow cytometric DNA index (D.I.-defined as the ratio of the DNA content of malignant cells to that of normal cells) and other prognostic factors (grade, stage of the disease, anatomical site, patients' sex and age) of 20 patients with colorectal cancer. The entire material was obtained from 20 unselected and previously untreated patients. This material consists of fresh tumoural or normal tissues taken after radical colectomy for the flow-cytometric analysis. A normal diploid DNA content was found in six tumours, the other fourteen being founded to be aneuploid. All non malignant tissue samples showed normal diploid DNA content. In the current series of cases we have found that DI was significantly associated with stage but not with grade, anatomical site or other prognostic factors. Our data indicates that cytometrically evaluated DI values have probably an independent predictive power for the clinical outcome of colorectal cancer patients.

Adult↗