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Biomedical subjects

M Riaz

Publications and source records attributed to M Riaz.

43 records · Page 3Linked to original sources

Effects of ultraviolet light on lecithin monolayers in the presence of fluorescein dyes and tetracycline drugs.

A Langmuir trough was employed to measure the effects of u.v. irradiation on the force area characteristics of monolayer films of lecithin spread on aqueous solutions of some dyes and tetracycline drugs both in the absence and presence of Ca2+ and Ni2+. Irradiation caused photochemical reactions which resulted in the expansion of the films and the extent of reaction was measured by the Photosensitive Indices. The reaction with tetracyclines was inhibited by adding Cu2+ or Ni2+ to the substrate. The kinetic orders of the reactions are given.

Copper↗

Photosensitization by fluorescein dyes and tetracycline drugs at an oil/water interface.

Measurements were made of the changes that occur in the interfacial tension of isopropylbenzene when floating on water containing between 10(-5) and 10(-3) M of various fluorescein dyes and tetracycline drugs and irradiated for up to 240 min with ultraviolet light. Singlet oxygen was found to be an active intermediate in the reactions. The results are discussed in relation to adverse photosensitization in-vivo due to fluorescein dyes and tetracycline drugs.

Chemical Phenomena↗

Primary meningococcal pericarditis.

We have described two patients with primary meningococcal pericarditis. The first patient required open surgical drainage. In the second patient, pericardiectomy was eventually required. Thirteen cases of primary meningococcal pericarditis have now been reported. All the patients survived, in contrast to purulent pericarditis of other causes.

Adolescent↗

The formation of short fibres from native cellulose by components of Trichoderma koningii cellulase.

Cellulolytic enzyme components of culture filtrates of Trichoderma koningii were fractionated on ionic and non-ionic forms of Sephadex and on cellulose powder (Whatman) and examined for their ability to hydrolyse soluble carboxymethyl-cellulose, and to saccharify, solubilize and form short fibres from native undegraded cellulose of the type found in cotton. DEAE-Sephadex provided two CM-cellulase components and a C(1) component; the C(1) component acted weakly and solely on cotton, forming soluble products but not short fibres. The ability to form short fibres was confined almost wholly to one of the CM-cellulase components which completely degraded cotton, minimally to soluble products and extensively to short fibres. The latter action was unaffected by the presence of the other two components. The two CM-cellulase components solubilized cellulose synergistically whereas the short-fibre-forming component and C(1) component were inhibitory.

Cellulose↗

The effects of maternal magnesium sulfate treatment on newborns: a prospective controlled study.

OBJECTIVE: To evaluate the effects of maternal magnesium sulfate treatment on newborn outcome. METHODS: Subjects were newborn infants delivered at > or = 34 weeks of gestation whose mothers received a minimum of 12 hours of intravenous MgSO4 therapy before delivery. Control infants were the next born infants of similar gestational age. Outcome recorded at delivery included Apgar scores, whether resuscitation was required, and whether respiratory depression or decreased tone were noted by the physician in attendance. Pneumocardiograms on magnesium-exposed and control infants, obtained within 6 to 18 hours after delivery, were analyzed postdischarge by a single investigator who was blinded to group. The nursery course, feeding patterns, time to first stool, and time to first void were recorded. All patient care decisions, including admission to the neonatal intensive care unit (NICU) or term nursery, were independent of study protocol. RESULTS: A total of 26 magnesium-exposed and 26 control infants were enrolled. The mean total dose of MgSO4 before delivery was 51.2+/-24 gm; the mean duration of therapy was 23.1+/-10 hours. The mean maternal serum magnesium level before delivery was 5.8+/-1.1 mg/dl. The infants' mean cord or initial serum magnesium level was 5.2+/-1.0 mg/dl, which correlated with the maternal magnesium level before delivery (r=0.81, p < 0.001). MgSO4-exposed infants had a higher incidence of hypotonia and lower median Apgar scores than control infants (p < 0.001). However, there was no association between adverse outcomes and maternal serum magnesium concentrations at delivery, duration of treatment, or dose of MgSO4. No difference in dose or length of maternal MgSO4 treatment was noted between infants admitted to term nursery and those admitted to NICU. Pneumocardiogram data were similar between MgSO4-exposed and control infants (all p > or = 0.16). There were no significant differences in number of episodes of feeding intolerance or in time to first stool or void between MgSO4-exposed and control infants (all p > or = 0.31). CONCLUSION: Infants born to mothers treated with MgSO4 were more likely to be hypotonic and have lower Apgar scores at birth. Beyond the immediate postdelivery period, there were no additional complications in this cohort attributable to prenatal MgSO4 exposure. We suggest that pediatricians attend deliveries of magnesium-exposed infants.

Apgar Score↗