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Biomedical subjects

I Mohamed

Publications and source records attributed to I Mohamed.

8 recordsLinked to original sources
PubMed2004

[Erythropoietin administration to preterm infants: comparison between subcutaneous and intravenous route].

OBJECTIVE: Our aim was to compare the effectiveness of a one-month treatment with recombinant human erythropoietine (rHuEpo) according to the administration route. METHODS: Retrospective study based on the data collection from medical files of 64 preterm infant hospitalized in the "institut de puériculture et de périnatalogie" (Paris) between January 13th, 2002 and April 13th, 2002. The first group (N =33) was treated by subcutaneous rHuEpo 750 IU/kg per week, in three injections by week, for one month. The second group (N =15) was treated by continuous infusion of rHuEpo in total parenteral nutrition 1050 IU/kg per week (30% augmentation to compensate the amount absorbed by the filter). The third group (N =16) received 750 IU/kg per week of rHuEpo in three direct intravenous injections. The effectiveness of rHuEpo was evaluated by the absolute reticulocyte count, the level of hemoglobin and the incidence of blood transfusion (multiple logistic analysis of variant and regression). RESULTS: The absolute reticulocyte count and hemoglobin level were significantly reduced after one month of treatment by continuous infusion of rHuEpo in total parenteral nutrition and direct intravenous injections compared with a one-month treatment by subcutaneous rHuEpo. Hemoglobine level were at 8.8 and 9.6 g/dl vs 10.3 g/dl (P =0.02) and absolute reticulocyte count at 123,000/mm3 and 190,000/mm3 vs 216,000/mm3 (p =0.001). The number of transfused infants was significantly increased with utilization of continuous (40%) and direct intravenous (75%) compared with those treated by subcutaneous route (21.2%) while the ferritin level and phlebotomy losses were not significantly different in the three groups. The number of blood transfusion was significantly linked to phlebotomy losses and administration route of rHuEpo. CONCLUSION: Our study tends to demonstrate that rHuEpo administered subcutaneously reduces significantly the number of transfusion in contrary to intravenous routes. Waiting for pilot study and new molecules, we recommend subcutaneous administration of rHuEpo to preterm infants 250 IU/kg three times weekly in the treatment of anemia of prematurity.

Anemia↗
PubMed2003

Refilling of cortical calcium stores in Paramecium cells: in situ analysis in correlation with store-operated calcium influx.

This is the first thorough study of refilling of a cortical calcium store in a secretory cell after stimulation in which we combined widely different methodologies. Stimulation of dense-core vesicle ("trichocysts") exocytosis in Paramecium involves a Ca(2+) -influx" superimposed to Ca(2+) -release from cortical stores ("alveolar sacs" (ASs)). In quenched-flow experiments, membrane fusion frequency rose with increasing [Ca(2+)](o) in the medium, from approximately 20-25% at [Ca(2+)](o) < or = 0.25 microM to 100% at [Ca(2+)](o) between 2 and 10 microM, i.e. close to the range of estimated local intracellular [Ca(2+)] during membrane fusion. Next, we analyzed Ca(2+)-specific fluorochrome signals during stimulation under different conditions. Treatment with actin-reactive drugs had no effect on Ca(2+) -signaling. In double trigger experiments, with BAPTA in the second secretagogue application (BAPTA only for stimulation and analysis), the cortical Ca(2+) -signal (due solely to Ca(2+) released from cortical stores) recovered with t(1/2) approximately 65 min. When ASs were analyzed in situ by X-ray microanalysis after different trigger times (+Ca(2+)(o)), t(1/2) for store refilling was similar, approximately 60 min. These values are similar to previously measured 45Ca(2+) -uptake by isolated ASs. In sum we find, (i) exogenous Ca(2+) increases exocytosis/membrane fusion performance with EC(50)=0.7 microM, (ii) Ca(2+) -signaling in this system is not sensitive to actin-reactive drugs, and (iii) refilling of these cortical calcium stores goes on over hours and thus is much slower than expected.

Actins↗
PubMed2002

Functional and fluorochrome analysis of an exocytotic mutant yields evidence of store-operated Ca2+ influx in Paramecium.

A non-discharge mutant of Paramecium tetraurelia (nd12-35 degrees C, lacking exocytotic response upon stimulation with the nonpermeable polycationic secretagogue aminoethyldextran, AED), in the pawnA genetic context (d4-500r, lacking ciliary voltage-dependent Ca2+ influx), was shown to lack (45)Ca2+ entry from outside upon AED stimulation. In contrast, cells grown at 25 degrees C behave like the wildtype. To check the functional properties in more detail, fluorochrome-loaded 35 degrees C cells were stimulated, not only with AED (EC(100) = 10(-6) M in wildtype cells), but also with 4-chloro-meta-cresol, (4CmC, 0.5 mM), a permeable activator of ryanodine receptor-type Ca2+ release channels, usually at extracellular [Ca2+] of 50 microM, and eventually with a Ca2+ chelator added. We confirm that pwA-nd12(35 degrees C) cells lack any Ca2+ influx and any exocytosis of trichocysts in response to any stimulus. As we determined by x-ray microanalysis, total calcium content in alveolar sacs (subplasmalemmal stores) known to be mobilized upon exocytosis stimulation in wild-type cells, contain about the same total calcium in 35 degrees C as in 25 degrees C cells, and Ca2+ mobilization from alveoli by AED or 4CmC is also nearly the same. Due to the absence of any AED-induced Ca2+ influx in 35 degrees C cells and normal Ca2+ release from stores found by x-ray microanalysis one can exclude a "CICR"-type mechanism (Ca2+-induced Ca2+ release) and imply that normally a store-operated Ca2+ ("SOC") influx would occur (as in 25 degrees C cells). Furthermore, 35 degrees C cells display a significantly lower basal intracellular [Ca2+], so that any increase upon stimulation may be less expressed or even remain undetected. Under these conditions, any mobilization of Ca2+ from stores cannot compensate for the lack of Ca2+ influx, particularly since normally both components have to cooperate to achieve full exocytotic response. Also striking is our finding that 35 degrees C cells are unable to perform membrane fusion, as analyzed with the Ca2+ ionophore, A23187. These findings were corroborated by cryofixation and freeze-fracture analysis of trichocyst docking sites after AED or 4CmC stimulation, which also revealed no membrane fusion. In sum, in nd12 cells increased culture temperature entails multiple defects, notably insensitivity to any Ca2+ signal, which, moreover, cannot develop properly due to a lower basal [Ca2+] level and the lack of Ca2+ influx, despite normal store activation.

Animals↗
PubMed1980

[Screening for hypertension by means of automatic measurement of the systolic blood pressure according to the Penáz-principle].

The plethysmomanometer after Penáz allows the automatic measurement of the systolic blood pressure in a finger artery. On the basis of the comparative measurements on 250 patients the result was a probably linear correlation with a correlation coefficient r = 0.821 between the systolic blood pressure after Riva-Rocci and the systolic pressure of the finger artery. Only in few cardiologic diseases (e.g. disturbances of the cardiac rhythm, severe cyanotic failures, arteriovenous fistules on the forearm) the devices cannot be used. Provided with adequate technical improvements the device might be used for the screening of hypertension.

Automation↗
PubMedDate not supplied

Laparoscopic cholecystectomy in patients with bilharzial portal hypertension.

OBJECTIVE: The purpose of this study was to evaluate the results of laparoscopic cholecystectomy in patients with bilharzial portal hypertension. METHODS: Patients who had gallstones and bilharzia had ultrasonographic assessment of peri-portal fibrosis, endoscopy, hemagglutination and rectal snip. Operating time, blood loss, hospital stay, time of return to work and operative mortality were recorded. Follow-up was two weeks, six weeks and six months after discharge. RESULTS: Twenty-five out of 450 patients, who had laparoscopic cholecystectomy, suffered from bilharzial portal hypertension. Ten patients had grade 1 varices, 10 had grade 2 varices, and 5 had grade 3 esophageal varices. All patients had varying degrees of peri-portal fibrosis as shown by ultrasound. Rectal snip showed schistosoma mansoni in 5 patients, and a hemagglutination test was positive in all. Two patients had conversion to open cholecystectomy. Mean operating time was 1 hour and 15 minutes. Average blood loss was 50 cc. Mean hospital stay for 23 patients was 48 hours. Average time of return to work was 2 weeks in 23 patients and 6 weeks in the 2 patients who had conversion. Twenty-two patients benefited from the operation. There was no mortality in this series. CONCLUSIONS: Laparoscopic cholecystectomy in patients with bilharzial portal hypertension is feasible and has low morbidity.

Adult↗