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Biomedical subjects

S M Hassan

Publications and source records attributed to S M Hassan.

At least 19 recordsLinked to original sources
PubMed1992

The role of host management in tick population changes on Rusinga Island, Kenya.

Contrary to patterns described elsewhere, tick numbers on Rusinga Island cattle drop markedly after the onset of the rainy season. One possible explanation is that this is related to seasonal differences in host behaviour, since cattle grazing on the island are restricted during the crop-growing season (the rainy season) and free grazing afterwards. In a field experiment, cattle were divided into two groups, free grazing and restricted, for 2 months each during the rainy season and during the dry season, and the number of ticks infesting each group was compared. In both seasons, the free-grazing group carried more ticks than the restricted group. Not only did the restricted group come into less contact with ticks, they were also exposed to tick-predating chickens for longer periods each day than the free-grazing group. Management practices that affect host behaviour should, therefore, be taken into consideration in tick population studies.

Animal Husbandry↗
PubMed1992

Laboratory and field observations on anti-tick properties of the plant Gynandropsis gynandra (L.) Brig.

A shrubby plant, abundant in east Kenya, Gynandropsis gynandra (L.) Brig., was shown to exhibit repellent and acaricidal properties to larvae, nymphs and adult Rhipicephalus appendiculatus and Amblyomma variegatum ticks. All stages of ticks avoided the leaves of the plant and a high percentage of the ticks which were continuously exposed to its leaves died; surviving ticks were weak and inactive but regained activity when exposed to fresh air. The effectiveness of the plant's leaves as a repellent and acaricide was most pronounced on nymphs and least pronounced on adults. Field investigations indicated that ticks were not found up to 2-5 m from the plant in areas where the plant was predominant. The potential of using the plant for tick control within an integrated tick management system in the resource-poor farming context in Africa was highlighted.

Animals↗
PubMed1992

Influence of exposure period and management methods on the effectiveness of chickens as predators of ticks infesting cattle.

Experiments undertaken on Rusinga Island, Kenya, indicated that Rhipicephalus appendiculatus (Neumann) was the predominant tick consumed on tick-infested cattle by chickens, followed by Amblyomma variegatum (Fabricius), Boophilus decoloratus (Koch) and Rhipicephalus evertsi evertsi (Neumann). The number of ticks consumed by chickens released with cattle in a 3 h release period was not significantly different from ticks consumed in a 4 h release period. In a free management system, chickens 1-3 months of age consumed more ticks than older ones; in a confined management system however, chickens 4-6 months of age consumed more ticks than younger birds. Although the numbers of ticks consumed by local and exotic breeds of chickens were not significantly different, a period of 8-10 weeks was necessary for the exotic breeds to become behaviorally adapted to tick predation on cattle. Local chickens bred in environments where cattle were absent took a shorter period of 4-6 weeks to adapt. It was concluded that the relatively large number of ticks consumed by each chicken during the 3 or 4 h release period is an indication that a good reduction of ticks on cattle can be achieved through tick predation by chickens. The preponderance of R. appendiculatus over other tick species consumed was a reflection of its relative abundance on cattle on the island rather than a selective preference for tick species.

Animal Husbandry↗
PubMed1992

Blood culture results as determinants in the organism identification of bacterial meningitis.

The diagnosis of bacterial meningitis depends on a lumbar puncture (LP). Sometimes, antibiotics are administered before a LP that is delayed owing to prior need for computerized tomography (CT) scan, technical problems, inability to obtain consent, or an unstable patient. We examined the accuracy of blood culture, cerebrospinal fluid (CSF) Gram's stain, and antigen detection by latex for organism identification of meningitis. All patients admitted to the Children's Hospital of Buffalo between January 1, 1984 and December 31, 1989 and having a CSF culture diagnosis of bacterial meningitis had their charts retrospectively reviewed. Patients excluded from the study were those with neural tube defects or CSF catheters, those admitted directly to the Intensive Care Nursery (ICN), those whose positive CSF cultures were determined to be a contaminant, those whose medical records were not found, or those older than 16 years. We analyzed a total of 178 patients with positive CSF cultures and the confirmed diagnosis of bacterial meningitis. Of 169 patients who had a blood culture performed, 86% had the organism responsible for meningitis recovered by this test, with the highest yield of 91% occurring in the 2.5-month to 24-month age group. Blood culture identified the bacteria in 94% of those patients with Haemophilus influenzae meningitis, and this yield increased to 100% when patients who had been pretreated with antibiotics were excluded. The combination of blood culture, CSF Gram's stain, and/or latex agglutination identified the causative bacteria in 92% of patients with meningitis. Blood culture, CSF Gram's stain, and latex agglutination are useful in identifying the organism causing pediatric meningitis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Predation on livestock ticks by chickens.

Chickens were shown to be natural predators of ticks. Rhipicephalus appendiculatus were recovered in large numbers from the crops and gizzards of chickens which had scavenged for 30 min-1 h among tick-infested cattle. Other ticks recovered were Amblyomma variegatum and Boophilus decoloratus. The numbers of ticks recovered ranged from 3 to 331, with an average of 81 per chicken. Cattle facilitated the predation of ticks by certain behavioural actions. Chickens also picked up both engorged and unengorged ticks seeded on vegetation, but unengorged ticks were preferred. The possibility of tick predation by chickens forming a viable biological control component in an integrated tick management system in Africa is discussed.

Animals↗
PubMed1991

Spectrophotometric determination of some MAO inhibitors using 7,7,8,8-tetracyanoquinodimethane and iodine monochloride.

Two simple and sensitive spectrophotometric methods are described for the assay of three MAO inhibitors: isocarboxazid, tranylcypromine sulphate and iproniazid phosphate. The first method is based on the formation of a highly coloured stable radical anion between the drug as an n-donor and 7,7,8,8-tetracyanoquinodimethane (TCNQ) as a pi-electron acceptor. Beer's law is obeyed in the concentration range 0.2-3, 0.2-4 and 0.5-4 micrograms ml-1 for isocarboxazid, tranylcypromine sulphate and iproniazid phosphate, respectively. The second method involves the use of iodine monochloride (ICl) as an sigma-acceptor. It was found that ICl reacts quantitatively only with isocarboxazid and tranylcypromine sulphate; with iproniazid phosphate results were very poor. Beer's law is obeyed in the concentration range 2-20 micrograms ml-1 for both drugs. The optimum experimental parameters for colour production in each case were determined. The percentage recoveries obtained were in accordance with those obtained by the official methods. The proposed methods are characterized by high sensitivity.

Chlorides↗
PubMed1991

Radioprotection of whole-body gamma-irradiation-induced alteration in some haematological parameters by cysteine, vitamin E and their combination in rats.

Radioprotective effect of cysteine, vitamin E and their combination on gamma-irradiation-induced alteration in some haematological parameters in male rats has been studied 24 and 48 hrs after whole-body gamma-irradiation at a dose level of 7.5 Gy. The results of this study reveal that gamma-irradiation caused a significant decrease in red blood cells (RBCs) count with insignificant change in hemoglobin level, 24 and 48 hrs postirradiation, gamma-irradiated rats showed as well a progressive decrease in their blood ATP, and serum-SH levels with a significant increase in blood glutathione (GSH) level. Administration of cysteine or vitamin E preceding gamma-radiation exposure gave a significant radioprotection to the above haematological parameters. However, combination of both agents afforded a better protection, so that most of the measured parameters were restored to the pre-irradiated values. Finally, the date demonstrate that the radioprotection provided by combined administration of vitamin E and cysteine is feasible and perhaps, even more efficient against radiation injury to RBCs. This will appreciate the usage of such combination in protecting the patient during radiotherapy.

Animals↗
PubMed1988

Application of difference spectroscopy to the determination of some pharmaceutically important nitro compounds.

A simple and selective spectrophotometric method for the determination of some pharmaceutically important nitro compounds has been developed. The suggested method depends upon the spectral changes induced by reduction using either Zn/HCl or Zn/NH4Cl. The different experimental parameters were studied and incorporated into the procedure. The mean percentage recovery ranged from 99 to 101. The proposed method was applied to the determination of the studied compounds in dosage forms, and the results obtained were compared favourably with those given with the compendial ones.

Indicators and Reagents↗
PubMed1979

Application of orthogonal functions to the spectrophotometric determination of calciferol in oily injections.

The method of orthogonal functions has been applied to the rapid spectrophotometric determination of vitamin D in oily injections. The method involves saponification of the sample and extraction of the unsaponifiable matter with ether. After cautious evaporation of ether, the residue is dissolved in isopropanol and the absorbance of the solution is measured in the range 246--296 nm at 10 nm intervals. For BPC injections, the saponification step may be omitted. A suitable dilution of the sample in isopropanol is measured in the range 250.5--300.5 nm at 10 nm intervals. Accurate and precise results are obtained in both cases.

Ergocalciferols↗
PubMed1978

Application of orthogonal functions to the determination of prednisolone and hydrocortisone in some pharmaceutical preparations.

Glenn's method of orthogonal functions has been successfully applied to the direct spectrophotometric determination of the title compounds in presence of phenylephrine and/or neomycin sulphate without preliminary separation. The proposed methods when applied to the analysis of market preparations are in good agreement with those of the triphenyltetrazolium colour reaction recommended as the official method.

Chemical Phenomena↗
PubMed1977

Application of orthogonal functions to the spectrophotometric determination of phenytoin and phenobarbitone in pharmaceutical preparations.

Orthogonal polynomial functions have been used in the simultaneous determination of mixtures of phenytoin and phenobarbitone in pharmaceutical preparations. The mean recovery (9 determinations) and coefficeint of variation were 100-0 +/- 1-4% for phenobarbitone and 100-0 +/-1-3% for phenytoin. Neither the delta A method of Pannerdan & Fontein nor a delta A modification of Vierordt's method of two-component analysis gave results of the same accuracy and precision as the proposed method.

Capsules↗