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Biomedical subjects

Z R Zhu

Publications and source records attributed to Z R Zhu.

At least 19 recordsLinked to original sources
PubMed2000

Glossina austeni (Diptera: Glossinidae) eradicated on the island of Unguja, Zanzibar, using the sterile insect technique.

An area-wide integrated tsetse eradication project was initiated in Zanzibar in 1994 by the International Atomic Energy Agency and the governments of Tanzania and Zanzibar, to eradicate Glossina austeni Newstead from Unguja Island (Zanzibar) using the sterile insect technique. Suppression of the tsetse population on Unguja was initiated in 1988 by applying residual pyrethroids as a pour-on formulation to livestock and by the deployment of insecticide impregnated screens in some of the forested areas. This was followed by sequential releases of gamma-sterilized male flies by light aircraft. The flies, packaged in carton release containers, were dispersed twice a week along specific flight lines separated by a distance of 1-2 km. More than 8.5 million sterile male flies were released by air from August 1994 to December 1997. A sterile to indigenous male ratio of >50:1 was obtained in mid-1995 and it increased to >100:1 by the end of 1995. As a consequence the proportion of sampled young females (1-2 ovulations), with an egg in utero in embryonic arrest or an uterus empty as a result of expulsion of a dead embryo, increased from <25% in the 1st quarter to >70% in the last quarter of 1995. In addition, the age structure of the female population became significantly distorted in favor of old flies (> or = 4 ovulations) by the end of 1995. The apparent density of the indigenous fly population declined rapidly in the last quarter of 1995, followed by a population crash in the beginning of 1996. The last trapped indigenous male and female flies were found in weeks 32 and 36, 1996, respectively. Time for 6 fly generations elapsed between the last catch of an indigenous fly and the end of the sterile male releases in December 1997.

Animals↗
PubMed2000

[Determination of alkyl alcohol polyoxyethylene ether by high temperature gas chromatography].

High temperature GC method has been developed for the separation and determination of alkyl alcohol polyoxyethylene ether (AEO). These AEO samples were separated on high temperature Al-coated fused-silica capillary column (0.1 micron bonded methyl silicon stationary phase, 25 m x 0.25 mm i.d.). The components of AEO sample were identified by GC/MS. The free alkyl alcohol and ethoxymer distribution of polyoxyethylene of AEO sample were determined by normalization method. The FID responses of typical components of AEO sample were determined, and their relative deviations were less than 4.1%. The recoveries of the free alkyl alcohol ranged from 96.5% to 98.1%. The relative standard deviations were less than 1.9%. In comparing with previous methods, this method is simple, fast and more reproducible.

Chromatography, Gas↗
PubMed1998

Field responses of Glossina austeni to sticky panels on Unguja Island, Zanzibar.

Two designs of cross-shaped sticky panels (XT and XLP) were compared with the royal blue-white legpanel (LPBuWh) in the Jozani forest on Unguja Island as trapping devices for male Glossina austeni. Single coloured royal blue (XTBu) and bi-coloured royal blue-white XT (XTBuWh) caught more than twice as many male G. austeni as the LPBuWh, whereas single coloured black XT trapped significantly fewer flies (10%) than the control LPBuWh. XT's in various horizontal and diagonal blue-white configurations likewise trapped more flies than the LPBuWh, except a horizontally striped blue-white XT which trapped fivefold fewer flies than the LPBuWh. Cross-shaped LP in the blue-white (XLPBuWh) and black-white (XLPB1Wh) combination scored significantly better than the control LPBuWh. Similar fly numbers were trapped with XTBuWh and XLPBuWh. Long-term trapping data indicated that the XTBu, XTBuWh and XLPBuWh were three- to fourfold more effective in trapping female flies than the LPBuWh. The landing bias on bi-coloured panels was low in the blue-white but more pronounced in the blue-black and white-black combinations and was affected by the type of sticky panel used. A high proportion (49%) of the flies alighted on the bottom corners of the XTBu panel, but landing positions were more scattered if white was added. Increasing the width of the XTBu from 70 to 120 cm improved the catch by a factor of two as compared with standard sized XTBu. The effect of doubling the height of the XT on total fly catch was negligible. At present, it is the XTBu which can be recommended as the best trapping device for male and female G. austeni.

Animals↗
PubMed1995

Microcomputer system for automatic identification of the Cryptococcus neoformans and its clinical application.

In this study, microcomputer image processing and pattern recognition technology, and the knowledge of morphology and optical characteristics of Cryptococcus neoformans were used for identification of Cryptococcus neoformans. Four groups of mice were lethally infected with standard strain, Wuhan strain, American B-2643 strain and Var. Shanghainesis of the Cryptococcus neoformans. The samples collected included mice brain, lung, kidney, liver, small intestine tissue and were observed under a light microscope. More than 600 images of the fungus were input into a microcomputer. A system of computer for automatic identification of the Cryptococcus neoformans was developed. The technique involved image preprocessing, image segmenting, coding of line-length on the edge, curve fitting, extracting of image feature, building of image library and feature data bank etc.. And then, 768 images of the clinical samples and other fungus samples whose morphological features tend to be confused with Cryptococcus neoformans were input into microcomputer and subjected to automatic identification. The Cryptococcus neoformans was accurately identified within 15 min, and the consistency rate with results of routine culture was 98%.

Animals↗
PubMed1995

Fatty acid composition of breast adipose tissue in breast cancer patients and in patients with benign breast disease.

Fatty acid composition of triglycerides (TGs) and phospholipids (PLs) in breast adipose tissue was analyzed in 73 female breast cancer patients and 55 patients with benign breast disease. No differences were observed in the dietary intake of the major fatty acids (i.e., palmitic, stearic, oleic, and linoleic acids) or in the proportion of TGs and PLs in breast adipose tissue between the two groups. In postmenopausal women, however, the dietary intake of eicosapentaenoic acid (20:5n-3) and docosahexaenoic acid (22:6n-3) was significantly lower in the breast cancer patients than in patients with benign breast disease. Accordingly, the percentage of docosahexaenoic acid of PLs in breast adipose tissue was significantly lower in breast cancer patients than in patients with benign breast disease among postmenopausal women. The stage of the breast cancer did not contribute to the observed alterations of fatty acid composition of PLs. Consonant with the previous epidemiologic data, the present results suggest that intake of the long-chain n-3 fatty acids (mainly derived from fish) may have a protective effect against breast cancer, particularly in postmenopausal women.

Adipose Tissue↗
PubMed1990

Image processing by microcomputer on ultrastructure of griseofulvin-resistant fungi in favus.

The ultrastructure of 5 griseofulvin-resistant fungi of favus was studied by image processing with microcomputer. It was found that the cell walls of the fungi consisted of 8 layers, and the inner layer containing cytoplasm was loose. It was also found that all structures within the cytoplasm possessed a 1-3 layers integral envelope with chromatins in the nucleus. These might be contributing factors in the development of resistance to griseofulvin. This multiple-layered, thick cell wall might act as a barrier responsible for the impermeability of the cell to griseofulvin.

Drug Resistance, Microbial↗
PubMed1990

Effects of sodium iodate on experimental subretinal neovascularization in the primate.

We investigated the role of the retinal pigment epithelium (RPE) in the development of subretinal neovascularization (SRN) induced by bilateral laser photocoagulation of the retinas in monkeys. RPE function was affected by a unilateral carotid injection of sodium iodate, a selective RPE toxin, before laser photocoagulation. This caused severe RPE damage in the ipsilateral eye, but did not affect the contralateral eye. After laser photocoagulation no SRN was demonstrable clinically or histopathologically in the ipsilateral eye; in contrast, active SRN showing extensive fluorescein leakage was found in the contralateral eye. These results suggest that RPE may play a role in the development of laser-induced SRN.

Animals↗
PubMed1990

[Pathogenesis of posterior capsular opacification after extracapsular cataract extraction].

Rabbit eyes were enucleated and examined by light and electronic microscope immediately after extracapsular surgery, and one day, one week, two weeks, one month and 6 months postoperatively. In addition, the technique of autoradiography was used to examine the status of cell hyperplasia of the lens epithelium. The results showed that posterior capsular opacification was due to migration of the lens epithelial cells onto the posterior capsule and transformation into fibroblasts. Fibrin exudate from postoperative uveitis was also a contributing factor.

Animals↗
PubMed1990

[Follow-up for posterior capsular opacification after extracapsular cataract extraction in 263 eyes].

263 eyes (252 patients) were followed up after extracapsular cataract extraction for posterior capsular opacifications. It was found that the incidence of this complication was higher after longer periods of follow-up, and also more frequent in younger patients. The etiology is due to migration and fibrosis of hyperplastic epithelial cells. Postoperative uveitis may be a contribution factor. Nd: YAG laser is the best means to perforate the posterior capsular opacification.

Adolescent↗
PubMed1989

Experimental subretinal neovascularization in the rabbit.

Subretinal neovascularization (SRN) in the rabbit was induced by subretinal injection of vitreous without rupture of Bruch's membrane. Eight of 26 eyes developed SRN. The incidence of SRN rose from 33% to 57% in a period of 4-40 weeks. Because of the absence of any fluorescein angiographic indication of SRN, these occult new vessels were identified by light and transmission electron microscopy. Histological examination showed that these newly formed vessels are composed of continuous capillaries with the morphologic characteristics of choriocapillaris, including diaphragmed fenestrations, basement membranes, and junctional complexes. The new vessels originated from the choriocapillaris and penetrated through Bruch's membrane into the subretinal space, where they were associated with the degenerated sensory retina and proliferating glial and/or RPE cells. This experiment provides a model of SRN without breaks in Bruch's membrane.

Animals↗
PubMed1989

Morphologic observations of retinal pigment epithelial proliferation and neovascularization in the rabbit.

Neovascularization and proliferation of the retinal pigment epithelium (RPE) was induced in the rabbit by subretinal injection of vitreous without rupture of Bruch's membrane. New vessels developed between the layer of RPE and photoreceptor outer segments, but were enveloped in proliferating RPE. For this reason they were occult; no fluorescein leakage was visible by angiography. The vessels were identified only by histologic examinations. Endothelial cell budding was the initial stage of vessel development, first seen two weeks after injection. The new vessels grew from the choriocapillaris, penetrated Bruch's membrane, and spread into the subretinal space, despite the absence of subretinal fluid. Fenestrations with diaphragms were found in the endothelial walls during the earliest stages of vessel formation, and were also present in the fully matured vessels. Intermediate junctional complexes were frequently observed among the endothelial cells. During maturation of these plexi, junctions changed from open to putative tight junctions. The mature vessels were ultimately completely enveloped by collagen and RPE cells. Our results show that all new vessels in this animal model have the morphologic characteristics of choriocapillaris. We assume that they leak fluorescein, as does the choriocapillaris, but that the dye has no opportunity to pool in the subretinal space and thus cannot be seen during angiography.

Animals↗
PubMed1989

Anti-shock effects of synthetic effective compositions of fructus aurantii immaturus. Experimental study and clinical observation.

Satisfactory results have been obtained in treating infective shock with injection of natural Fructus Aurantii immaturus (nat-FAI). The results of animal experiments and clinical observations on the anti-shock effects of the synthetic effective compositions of Fructus Aurantii immaturus (syn-FAI) are reported. The cardiac output increased from 0.53 to 0.87 L/min (P less than 0.01), and the cardiac index increased from 0.99 to 1.63 L/m2/min (P less than 0.01) in the endotoxic shock dogs after the treatment with syn-FAI. At the same time the blood stream in bulbar conjunctiva became accelerated and the dilated microvessels began to get smaller in most dogs. Of fifty children with infective shock treated with syn-FAI, forty-eight showed curative effects, with a total effective rate of 96%. The anti-shock effective compositions in FAI have been proved to be synephrine and N-methyltyrosamine. Moreover, syn-FAI has shown a more stable property, less side-effects and better clinical results than nat-FAI.

Adrenergic alpha-Agonists↗
PubMed1988

Cellular proliferation induced by subretinal injection of vitreous in the rabbit.

A new experimental model of subretinal cellular proliferation, based on injection of autologous vitreous into the subretinal space of rabbits, was studied by light and electron microscopy. As early as five days after injection, proliferation of retinal pigment epithelial (RPE) and retinal glial cells was observed in the subretinal space. These morphologically distinct proliferating cells were sometimes joined by junctional complexes. Morphologically, the proliferating RPE cells resembled either RPE cells or fibroblasts. Some proliferating RPE cells also retained their epithelial characteristics (ie, basement membranes and cell junctions), while others were partially dedifferentiated and showed some embryonic features. New formation of melanin could be identified within the proliferated RPE cells, which could account, in part, for the hyperpigmentation at the site of the bleb caused by the injection of vitreous. The results demonstrated that injection of autologous vitreous into the subretinal space can lead to subretinal proliferation of retinal glial and RPE cells in the rabbit.

Animals↗
PubMed1988

Breakdown of Bruch's membrane after subretinal injection of vitreous. Role of cellular processes.

It was recently shown that the injection of autologous vitreous beneath the retina of rabbits leads to retinal degeneration, subretinal cellular proliferation and neovascularization. The current study, using electron microscopy, was designed to determine the cellular processes involved in the breakdown of Bruch's membrane in this model. Bruch's membrane was not mechanically damaged by the injection and appeared intact for the first 1 to 2 days after injection. Subsequently, numerous breaks in Bruch's membrane were found associated with invasion of macrophages and fibroblasts; in addition, budding and penetration of retinal pigment epithelial (RPE) and choroidal endothelial cells into Bruch's membrane were noted. Although it was not proven that these cells, per se, were responsible for the breaks, that these cells actively penetrate Bruch's membrane is a reasonable hypothesis.

Animals↗
PubMed1988

Experimental changes resembling the pathology of drusen in Bruch's membrane in the rabbit.

Drusen-like changes in Bruch's membrane following subretinal injection of vitreous in the rabbit were studied by electron microscopy. A sequence of changes is seen that closely panellels those observed during drusen formation in primates. The initial event is the budding of retinal pigment epithelial (RPE) cells into Bruch's membrane; the buds, which contain cytoplasm and plasma membrane, are connected to the cytoplasm of the parent RPE cell. Most buds are surrounded by basement membrane, but some penetrate RPE basement membrane into Bruch's membrane. Later, RPE buds completely separate from the parent RPE cell and show degeneration and disintegration. Finally, drusen-like material, including vesicular, granular, tubular and linear structures, is dispersed from the bud remnant into Bruch's membrane. The study described herein thus supports the hypothesis that drusen are the result of budding from the RPE.

Animals↗