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Biomedical subjects

Z Jin

Publications and source records attributed to Z Jin.

At least 109 records · Page 6Linked to original sources
PubMed1997

X-ray microanalysis of uterine epithelial cells in culture.

The ionic composition of the uterine fluid, secreted by the endometrium, is of importance for fertilization and embryonic development. Little, however, is known about the ion transport mechanisms in the uterine epithelial cells. Because it is difficult to study ion transport in this tissue in situ, a method was developed to culture mouse uterine epithelial cells for X-ray microanalysis in the electron microscope, in order to allow the study of ion transport. Our data suggest the presence of a number of ion transport mechanisms in the cultured uterine epithelial cells. The cells appear to possess a ouabain-sensitive Na(+)-K(+)-ATPase, an amiloride-sensitive Na(+)-H+ antiporter, cAMP- and Ca(2+)-activated chloride channels, and volume-activated chloride efflux and influx mechanisms. In addition, chloride efflux can be stimulated by cholinergic and alpha-adrenergic agonists. Only a few of these mechanisms had been studied previously in the uterine epithelium.

Acetylcholine↗
PubMed1997

Maternal HIV-1 viral load and vertical transmission of infection: the Ariel Project for the prevention of HIV transmission from mother to infant.

Most HIV-1 infections of children result from mother-to-infant transmission, which may occur perinatally or postnatally, as a consequence of breast feeding. In this study, the influence of maternal viral load on transmission of infection to infants from non-breast-feeding mothers was examined using samples of plasma and peripheral blood mononuclear cells (PBMCs) collected at several time points during pregnancy and the 6-month period after delivery. These samples were analyzed by several quantitative methods, including virus cultures of PBMCs and polymerase chain reaction (PCR) assays for HIV-1 RNA in plasma and DNA in PBMCs. The risk of transmission increased slightly with a higher viral load, but transmission and nontransmission occurred over the entire range of values for each assay. No threshold value of virus load was identified which discriminated between transmitters and nontransmitters. We also noted a significant rise in viral load and a decline in CD4+ lymphocytes in the six months after delivery. These findings suggest that a high maternal viral load is insufficient to fully explain vertical transmission of HIV-1. Additional studies are needed to examine the post-partum increase in viremia.

Anti-HIV Agents↗
PubMed1997

Rail supporting transducer posts for three-dimensional force measurement.

Parallel bars supported on transducer posts were designed, instrumented and calibrated to measure three-dimensional (3-D) forces applied to the rails. These instrumented rails were designed for measuring forces applied by paraplegic patients during development and evaluation of functional electrical stimulation (FES) patterns for standing, side stepping, and ascending and descending stairs. The focus of this study was on the adaptation of the system for measuring support forces during stair climbing and descent. The specific problems with crosstalk among the three axes, nonlinearity, and hysteresis were investigated. In this design, the crosstalk between axes was less than 5%, nonlinearity was less than 2% of full scale, and force accuracy was better than 5%.

Biomechanical Phenomena↗
PubMed1997

[Study on Servo-null method for direct measurement of microvascular pressure by micropuncture technique].

The dynamic microvascular pressures in the mesentery of spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats were measured and recorded by using the Servo-null microvascular pressure measuring system (Model 4A, IPM, Inc., San Diego, USA) with glass micropipettes whose tips were 1.0-5.0 microns in diameter and had been beveled very sharply at an angle of 25 degree. Microvascular pressures were measured in two groups of microvessels: large, 25-45 microns; small, 15-25 microns. Mean microvascular pressures (Pm) of large and small arterial microvessels in SHR were 6.0 +/- 7.0 kPa and 4.8 +/- 0.6 kPa, respectively. In WKY rats, Pm were 4.2 +/- 0.6 kPa and 3.6 +/- 0.6 kPa, respectively. Pm of comparable types of arterial microvessels in SHR and WKY rats was significantly different. No significant difference of Pm in small venous vessels was found between SHR and WKY rats.

Animals↗
PubMed1997

X-ray microanalysis of uterine secretion in the mouse.

In an attempt to characterize ion transport mechanisms in the uterine epithelium the effect of diuretics on the elemental composition of the uterine secretion was investigated by X-ray microanalysis. Mice were treated with a variety of diuretics and Sephadex beads were incubated in situ in the uterus where they absorbed the uterine secretion. In animals treated with furosemide, bumetanide, or amiloride, the concentration of Na, K, and Cl in the uterine secretion was significantly decreased. After treatment with acetazolamide, only the K concentration was significantly decreased. Treatment with diuretics also decreased the concentration of P and S in the uterine secretion, indicating that less mucus was absorbed to the Sephadex beads. Transmission electron microscopy confirmed that treatment with amiloride and furosemide decreased the amount of mucus covering the epithelium. A possible explanation is that because of lack of water, the uterine mucus cannot leave the lumen of the uterine glands and reach the surface of the epithelium where the beads are. The data strongly suggest that Na+, K+, and Cl- transport in the uterine epithelium is dependent on a basolaterally situated Na(+)-(K+)-Cl(-)-cotransport mechanism. Disturbance of normal ion and water transport apparently affects the composition and consistency of the mucus, which may help explain abnormalities in cervical mucus in patients with cystic fibrosis.

Acetazolamide↗
PubMed1997

Effects of nicotine on the uterine epithelium studied by X-ray microanalysis.

The composition of the uterine fluid is of importance for the development of the embryo. The ionic composition of the uterine fluid is determined by transport processes in the uterine epithelium. The aim of the present study was to investigate whether nicotine can affect the ion transport processes and ultrastructure of the uterine epithelium in mouse and rat. The effects of nicotine on the uterine epithelium were compared with those on kidney and liver. Nicotine was administered to mice as an intraperitoneal injection of a 1 microgram/l nicotine solution twice daily for 8 days, or in the drinking water (108 microM nicotine) for 15 days, whereas rats received nicotine in their drinking water for 10 days (54 or 108 microM nicotine). In addition, primary cultures of endometrial cells were exposed to nicotine in vitro. Changes in morphology were examined by transmission electron microscopy and changes in elemental content by X-ray microanalysis. Nicotine caused a significant decrease in the concentrations of Na, K, and Cl in the uterine fluid and in the endometrial cells in situ. Similar changes in elemental concentrations were observed in endometrial cells in vitro. Ultrastructural changes in endometrial cells included swollen and damaged mitochondria. In liver and kidney much smaller effects of nicotine on the elemental composition of the cells were observed. However, marked ultrastructural effects were seen in the kidney: a reduction in mitochondrial size and an increase in lysosomal volume. It is concluded that nicotine directly interferes with fluid transport across the uterine epithelium.

Animals↗
PubMed1997

Risk of relapse in leprosy after fixed-duration multidrug therapy.

Between 1986 and 1995, 8307 leprosy patients have completed fixed-duration multidrug therapy (FD-MDT) and were followed annually for possible relapse. The mean relapse rate for multibacillary (MB) leprosy is 0.15/1000 person-years (py) and for paucibacillary (PB) 0.55/1000 py. There is no difference in the relapse rates between patients with or without chemotherapy before FD-MDT. In MB patients, the five relapses occurred between 4 and 7 years; in PB patients, five relapses occurred at 4-5 years after FD-MDT. Six additional PB relapses self-reported 1-4 years after the 5-year surveillance period and were not included in the relapse rates. Most PB patients relapsed into MB due to wrong classification and insufficient therapy. For the known 62 irregular MB patients the cumulative relapse rate is 6.5%.

Anti-Infective Agents↗
PubMed1997

Standardization of low attenuation area versus total lung area in chest X-ray CT as an indicator of chronic pulmonary emphysema.

We examined the methods for measuring the LAA% (100 x low attenuation area/total lung area) on thoracic X-ray CT scans in order to develop a useful indicator of chronic pulmonary emphysema (CPE). First, we modified the method for calculating the LAA% to be applicable by the programming tool installed in a commercially available CT machine in order to minimize manual procedures. This new method proved to be applicable in all CT machines produced after 1987. Second, we examined the difference in the Hounsfield Unit (HU) between different CT machines using two kinds of phantoms. One phantom was composed of Styrofoam, which has a density similar to the low attenuation areas. The other phantom was composed of Styrofoam and water, which has a density similar to the lung. We proved that the difference of LAA% with the correct value was 5% at maximum among four different CT machines. Thus, the phantom developed in the present study may play an important role in the standardization of HU. Finally, the possibility of decreasing the X-ray levels was examined. Twenty-five percent of the standard electrical current provided the same LAA% in cases where the subject was an established CPE patient, whereas the LAA% was overestimated in subjects with a normal LAA% value. However, a correction using a linear regression equation may be possible in the latter cases. It may be concluded that LAA% analysis can easily be performed in many city hospital, without much investment of manual procedures or any corrections to the HU levels between different CT machines. This method may be useful as a routine follow up for CPE patients because of the smaller irradiated dose given when using a CT machine.

Algorithms↗
PubMed1997

The selective recognition of antibody IgY for digestive system cancers.

Biological methods for cancer therapies are very important. A small and efficient target carrier is the key component for anti-cancer drugs. In our laboratory, the antibody IgY was extracted from egg yolk of a SPF hen. The SPF hen was immunized with an antigene of P110 protein which was purified from human stomach cancer MGC-803 cells. Results indicated that the antibody IgY can specifically recognize gastrointestinal system cancers. It may become an important carrier for antitumorigenic drugs.

Adenocarcinoma↗
PubMed1997

[Effects of amniotic fluid embolism-like plasma on isolated perfused rabbit lungs].

OBJECTIVE: In order to investigate whether amniotic fluid could induce the release of mediators from blood cells which would damage the lungs, an isolated perfused rabbit lung (IPRL) was exposed to amniotic fluid embolism-like plasma (AFEP) and the injury of AFEP to lungs and the protective effects of ibuprofen were studied. METHODS: 10 ml human amniotic fluid and 50 ml heparized rabbit blood were incubated together with or without ibuprofen (600 micrograms) at 37 degrees C for 30 min and centrifuged. Supernatants were taken and were referred to as AFEP or ibuprofen AFEP. IPRL was perfused with AFEP, ibuprofen AFEP, simple amniotic fluid (SAF), supernatant of amniotic fluid (SnAF), rabbit plasma (RP) and control NS. The changes of pulmonary artery pressure (PAP), respiratory pressure (RP) and lung weight were recorded by computer and compared with control NS group. RESULTS: In groups of SAF, SnAF and RP PAPs were slightly elevated (0.13-0.6 kPa, P > 0.05), and lung weights were not changed. AFEP induced the increase of PAP (3.52 +/- 0.64 kPa, P < 0.05) and lung weight (4.0 +/- 1.0 g, P < 0.01) with the development of lung edema. Administration of ibuprofen prevented partially the APEP-induced increase of PAP (1.87 +/- 0.43 kPa, P < 0.05) and lung weight (0.4 +/- 0.3 g, P < 0.01). CONCLUSION: Amniotic fluid may induce the release of mediators from blood cells, and the latter is the important cause resulting in the pathological changes of lungs in amniotic fluid embolism. Ibuprofen may reduce partially the APEP-induced lung injury.

Animals↗
PubMed1997

[Inhibitory effect of ganciclovir on the HSV1-tk positive subcutaneous tumors transplanted with human ovarian cancer in nude mice].

OBJECTIVE: To investigate the inhibitory effect in vivo of ganciclovir (GCV) on the growth of human ovarian cancer cells (AO) transducted with the thymidine kinase gene of herpes simplex virus I type (HSV1-tk). METHODS: Tumors were induced in nude mice by subcutaneous injection of AO cells and AO cells carried with HSV1-tk gene from China strain (AO/HSV1-tk cells). When the growing tumors were visible, GCV was injected daily into the peritoneum of the nude mice. RESULTS: The average weights of survived AO/HSV1-tkc tumors and AO tumors treated with GCV were 0.087 +/- 0.036 g and 0.661 +/- 0.260 g respectively. Most of the survived AO/HSV1-tkc cells treated with GCV were characterized by hypertrophy and necrosis, but their nuclear chromatins predominantely took the forms of heterchromatins. CONCLUSIONS: GCV could effectively inhibit the growth of HSV1-tk positive human ovarian cancer cells in vivo, but the nuclei of the survival tumor cells appeared to proliferate actively. As the same results of in vitro experiments, this may suggest that HSV1-tk/GCV gene therapeutic system might be combined with S-phase chemotherapy to increase the long-term effect.

Animals↗
PubMed1997

[Clinical diagnostic valuation cine magnetic resonance coronary angiography].

OBJECTIVE: To assess the ability of imaging coronary arteries noninvasively with magnetic resonance angiography technique (MRCA) and its diagnostic value in coronary artery disease. METHODS: MRCA was performed on 33 subjects, including 12 healthy adult volunteers and 21 patients with available recent X-ray contrast angiography (XCA) results. MRCA technique consisted of a gradient echo sequence (Turbo-Cine), two-dimensional acquisition, fat suppression, peripheral gating. Subjects were imaged in supine position using a standard body coil, without breath-hold. RESULTS: All 33 subjects were imaged successfully. Identification of the coronary artery was possible for the right coronary, left main stem, left anterior, and left circumflex arteries respectively in 97%, 100%, 91% and 91% with a visualized mean length of 51 +/- 15 (28-80 mm), 11 +/- 4 (4-22 mm), 44 +/- 13 (24-66 mm), 40 +/- 12 (20-66 mm). In the 21 subjects with available XCA results, 78% (29/37) proximal stenoses of the coronary arteries were detected with MRCA. CONCLUSION: At current stage, MRCA can depict most of the hemodynamically significant proximal stenoses but not the distals. This procedure can be used as an alternative imaging application under certain clinical indications.

Adult↗
PubMed1996

Molecular characterization of a novel, developmentally regulated small embryonic chaperone from Caenorhabditis elegans.

Low molecular weight chaperones inhibit protein aggregation and facilitate refolding of partially denatured polypeptides in cells subjected to physical and chemical stresses. The nematode Caenorhabditis elegans provides a system amenable for investigations on roles for chaperone proteins in normal homeostasis and development. We characterized a C. elegans gene and cDNAs that encode a novel, small embryonic chaperone-like protein (SEC-1) that is composed of 159 amino acids. The central core of SEC-1 (residues 45-126) is approximately 40% identical with a corresponding segment of mammalian Hsp27 and alphaB crystallin. Expression of SEC-1 in Escherichia coli confers thermotolerance on the bacterium. SEC-1 mRNA is evident only in C. elegans oocytes and developing embryos. Translation and accumulation of SEC-1 protein is temporally coupled with a prolonged burst of intense protein synthesis and rapid mitogenesis during early embryogenesis. As the rate of protein synthesis decreases during late embryogenesis, levels of SEC-1 and its cognate mRNA decline precipitously. Induction/deinduction of SEC-1 is precisely regulated by intrinsic developmental factors rather than extrinsic stresses. In vivo injection of C. elegans oocytes with antisense oligonucleotides that complement the 5'-end of SEC-1 mRNA arrests nematode development at an early stage after fertilization. Thus, SEC-1 appears to be adapted to perform essential functions in early embryogenesis.

Amino Acid Sequence↗
PubMed1996

Alterations in H-ras1 promoter conformation during N-nitroso-N-methylurea-induced mammary carcinogenesis and pregnancy.

We previously demonstrated that H-ras1 oncogene mutations detected in N-nitroso-N-methylurea (NMU)-induced mammary tumors arose as background mutations within rat mammary cells (RMCs) and that NMU promoted the outgrowth of these preexisting mutants. We have now detected a putative DNA structure in the H-ras1 promoter of RMCs in vivo that was absent in NMU-induced mammary tumor cells. Analysis of the promoter in RMCs as a function of time after exposure to carcinogens indicated that NMU, but not 7,12-dimethylbenz(a)anthracene, initiated the loss of this structure with a half-life of 7 days. Although loss of the structure was irreversible in cells that gave rise to tumors, it was restored in normal RMCs by 120 days after exposure and was present in normal RMCs of animals bearing tumors, even 1 year after NMU exposure. The structure was also abrogated in RMCs during pregnancy and restored after lactation was terminated, suggesting that reversible regulation of the structure by hormones contributed to normal RMC growth. Thus, NMU may promote abnormal RMC growth by mimicking the effects of hormones on DNA conformation. We hypothesize that the NMU-induced alterations in promoter conformation irreversibly deregulates H-ras1 expression in initiated cells, thereby increasing the phenotypic penetrance of the conditional H-ras1 mutations.

Animals↗
PubMed1996

Structure and function of gustatory neurons in the nucleus of the solitary tract: II. Relationships between neuronal morphology and physiology.

This study employed intracellular recording and labeling techniques to examine potential relationships between the physiology and morphology of brainstem gustatory neurons. When we considered the neuronal response to the four "prototypic" tastants, we were able to demonstrate a positive correlation between breadth of responsiveness and the number of dendritic branch points. An analysis of the response to eight tastants also revealed an association between dendritic spine density and the breadth of responsiveness, with more narrowly tuned neurons exhibiting more spines. Interestingly, a neuron's "best response" was a relatively poor predictor of neuronal morphology. When we focused on those neurons that responded to only one tastant, however, a number of potentially important relationships became apparent. We found that the cells that only responded to quinine were smaller than the neurons that only responded to NaCl, HCl, or sucrose. The HCl-only neurons, however, were more widespread in the rostrocaudal dimension that the neurons that only responded to NaCl. A number of additional structure-function relationships were identified when we examined the neuronal response to selected tastants. We found that neurons that responded to sucrose but not quinine, as well as neurons that responded to quinine but not sucrose, were more widespread in the mediolateral dimension than neurons that responded to both sucrose and quinine. We also discovered that the neurons that responded to NaCl, but not to NH4Cl or KCl, were larger than neurons that responded to all three salts. We believe that these results support the hypothesis that there are relationships between the structure and function of gustatory neurons in the nucleus of the solitary tract, with the data highlighting the importance of three themes: 1) the relationship between dendritic specializations and tuning, 2) the relationship between dendritic arbor orientation and response properties, and 3) the potential importance of stimulus-specific neurons.

Animals↗
PubMed1996

[Changes in sexual hormones and bone metabolism disorder in postmenopausal NIDDM patients].

In the present study the bone mineral content (BMC) was measured with a single photoabsorptionmeter in 31 diabetic menopausal females and 45 normal menopausal females, simultaneously the serum level of estradiol (E2), testosterone (T), parathyroid hormon (PTH) and calcitonin (CT) were measured with radioimmunoassay. The results showed, BMC, E2 and CT in diabetic group were significantly lower than in the control group. The serum level of PTH in diabetic group was significantly higher than in the control group. The multiple regression-analysis showed that chiefly the level of E2 in the diabetic group was closely related with BMC. Serum E2 stimulate directly the osteoblasts for the bone reconstruction and increased the bone tissue sensibility to PTH. CT is the antagonistic hormone of PTH and protects the bone mineralization. Hyperglycemia may cause the damage of ovarium and decreased E2-secretion. The lowered E2 level results in combination with elevated PTH and lowered CT level in serum obviously, in loss of a large amount of bone mineral content and in developing the diabetic osteoporosis.

Aged↗