Search PubMed⌕ Search

Biomedical subjects

R Yang

Publications and source records attributed to R Yang.

280 records · Page 16Linked to original sources
PubMedDate not supplied

Review of arteriovenous fistula care.

The patient with End Stage Renal Failure is largely dependent upon haemodialysis for survival. Vascular access is the vital lifeline. This paper provides a review of the literature and aims to advocate the advantages of arteriovenous fistulae compared with other vascular access. It will discuss the main causes of thrombosis in arteriovenous fistula failure, measurements of early detection of venous stenosis and the care of an arteriovenous fistula to ensure its patency. The responsibility of the dialysis nurse is also considered.

Arteriovenous Shunt, Surgical↗
PubMedDate not supplied

Reduced recovery of a Cryptococcus neoformans adherence mutant from a rat model of cryptococcosis.

Stable mutants of Cryptococcus neoformans (strain CSF-1) induced by treatment with ultraviolet light and nitrosoguanidine were isolated that demonstrated reduced adherence to glial cells in culture. Adherence of the mutants, as measured by a radiometric assay, was reduced by 50-70% of that attained for the parent CSF-1 strain. The adherence mutants appeared to be phenotypically similar to the CSF-1 strain. However, all but one mutant (designated as CSF-23) demonstrated slightly slower growth rates than the wild-type strain. The CSF-1 and CSF-23 strains were injected intravenously and intratracheally into normal rats and rats immunosuppressed by cyclophosphamide treatment, and the organ distribution and recovery of viable yeasts determined over 2-96 h. During this relatively short period of observation the majority of the yeasts were localized in the lungs. By either route of injection, the recovery of the CSF-23 adherence mutant was reduced by as much as 90% of that obtained for the wild-type strain. The results indicated that host cell adherence may be important for the persistence of cryptococci in tissue and that further studies with the adherence mutants are warranted.

Animals↗
PubMedDate not supplied

Discrepancy between cytogenetic and FISH results on an amniotic fluid sample of 45,X/46,X,idic(Y)(p11).

The presence of abnormal ultrasound markers showing a thick nuchal fold with short middle phalanx of the fifth finger in an otherwise normal-appearing female fetus led to the sampling of amniotic fluid at 16 weeks gestation. Cytogenetic analysis with routine G-banding showed a 45,X karyotype in all 20 cells analysed from two flasks. However, fluorescent in situ hybridization on uncultured cells showed presence of a Y signal in 9 cells, 11 cells showing a single signal for the X. A cytogenetic analysis of the fetal blood at 23 weeks confirmed the presence of two cell lines, 45,X and 46,X, idic(Y)(p11). The couple opted to have the pregnancy terminated. However, the fetus was not available to carry out confirmatory tests.

Amniotic Fluid↗
PubMedDate not supplied

Treatment with growth hormone enhances contractile reserve and intracellular calcium transients in myocytes from rats with postinfarction heart failure.

BACKGROUND: Recombinant human growth hormone (GH) improves in vivo cardiac function in rats with postinfarction heart failure (MI). We examined the effects of growth hormone (14 days of 3.5 mg. kg-1. d-1 begun 4 weeks after MI) on contractile reserve in left ventricular myocytes from rats with chronic postinfarction heart failure. METHODS AND RESULTS: Cell shortening and [Ca2+]i were measured with the indicator fluo 3 in myocytes from MI, MI+GH, control, and normal animals treated with GH (C+GH) under stimulation at 0.5 Hz at 37 degrees C. Cell length was similar in MI and MI+GH rats (150+/-5 and 157+/-5 microm) and was greater in these groups than in the control and C+GH groups (140+/-4 and 139+/-4 microm, P<0.05). At baseline perfusate calcium of 1.2 mmol/L, myocyte fractional shortening and [Ca2+]i transients were similar among the 4 groups. We then assessed contractile reserve by measuring the increase in myocyte fractional shortening in the presence of high-perfusate calcium of 3.5 mmol/L. In the control and C+GH groups, myocyte fractional shortening and peak systolic [Ca2+]i were similarly increased in the presence of high-perfusate calcium. In the presence of high-perfusate calcium, both myocyte fractional shortening and peak systolic [Ca2+]i were depressed in the MI compared with the control groups. In contrast, myocyte fractional shortening (14.1+/-.9% versus 11.1+/-.9%, P<0.05) and peak systolic [Ca2+]i (647+/-43 versus 509+/-37 nmol/L, P<0.05) were significantly higher in MI+GH than in MI rats and were comparable to controls. Left ventricular myocyte expression of sarcoplasmic reticulum Ca2+ ATPase 2 (SERCA-2) and left ventricular SERCA-2 protein levels were increased in MI+GH compared with MI rats. CONCLUSIONS: Calcium-dependent contractile reserve is depressed in myocytes from rats with postinfarction heart failure. Long-term growth hormone therapy increases contractile reserve by restoring normal augmentation of systolic [Ca2+]i in myocytes from rats with postinfarction heart failure.

Analysis of Variance↗
PubMedDate not supplied

Effect of electroacupuncture on the level of preproenkephalin mRNA in rat during penicillin-induced epilepsy.

Our previous studies have shown that seizure induced by injecting penicillin (0.24 mg/2 microliters) into hippocampus could be inhibited by electroacupuncture (EA) probably via decreasing enkephalin content in hippocampus. To determine whether this change reflected the peptide synthesis, preproenkephalin (PPE) mRNA was detected in hippocampus and some other limbic structures during seizure and after EA treatment by in situ hybridization. Four hours after injecting penicillin into hippocampus, PPE mRNA levels were significantly increased by 10 folds in entorhinal cortex, subiculum, CA1 area of hippocampus, amygdaloid nucleus and piriform cortex, whereas EA treatment apparently attenuated the seizure-induced increase of PPE mRNA in the areas mentioned above. The results indicated that EA may regulate the biosynthesis of PPE in hippocampus during seizure by an alteration in gene transcription.

Animals↗
PubMedDate not supplied

20-Cyclopropyl-cholecalciferol vitamin D3 analogs: a unique class of potent inhibitors of proliferation of human prostate, breast and myeloid leukemia cell lines.

We have synthesized and studied the ability of a series of nine novel 1,25 dihydroxyvitamin D3 [1,25(OH)2D3] analogs to inhibit clonal growth of myeloid leukemic cells (HL,60), prostate (LNCaP, PC-3 and DU-145) and breast (MCF-7) cancers cells. DU-145 cells were actively resistant to compounds (cmpd) with all of these modifications, but when we removed C-19 (E, 1,25-Dihydroxy-23E-ene-26,27-hexafluoro-19-nor-20-cyclopropy l- cholecalciferol) an analog resulted that was inhibitory against all three prostate cell lines, breast and HL-60 cell lines. Further analysis showed that pulse exposure (3 days, 10(-7) M) to this analog was enough to inhibit clonal growth of PC-3 cell by 50%. Furthermore, cmpd E increased the number of PC-3 cells in G1 and decreased the number in S phase. 1,25(OH)2D3 mediates its biological activities through specific binding to the vitamin D3 receptor (VDR) and subsequent association with vitamin D3 response elements (VDRE) in genes modulated by 1,25(OH)2D3. Several novel vitamin D3 cmpds have recently been identified which have 5- to 1000-fold greater abilities to induce differentiation and to inhibit proliferation of prostate cancer, breast cancer and HL-60 leukemic blast cells as compared to the parental 1,25(OH)2D3. To clarify the mechanism by which nine of these vitamin D3 analogs mediate their remarkably potent biological activities, we have investigated their abilities in PC-3 prostate cancer cells to transactivate a chroramphenicol acetyl transferase (CAT) reporter gene containing a VDRE from the human osteocalcin gene attached to a thymidine kinase minimal promoter. Dose-response studies of Cmpd E showed that in serumless culture conditions, transactivation of the VDRE-CAT was stronger than cmpd J [1,25(OH)2D3]. Then, we investigated the effects of vitamin D3 cmpd J in mice. Our data showed the growth inhibitory action of the vitamin D3 cmpd E in prostate cancer cell line (PC-3) was stastically superior to the non-treatment group in terms of tumor size and tumor weight in mice. In summary, this is the first report of a potent series of 20-cyclopropyl-cholecalciferol vitamin D3 analogs with the ability to inhibit proliferation of LNCaP, PC-3, DU-145, MCF-7 and HL-60 cell lines. These cmpds may mediate their potent anti-proliferative activities through a cell cycle arrest pathway.

Animals↗
PubMedDate not supplied

[Type 1 glucose transporter (Glut1) deficiency: manifestations of a hereditary neurological syndrome].

AIM: To define this genetic syndrome. DEVELOPMENT: The constellation of infantile epilepsy, acquired microcephaly and hypoglychorrachia is characteristic of glucose transporter type 1 (Glut1) deficiency syndrome, a prototype neurometabolic disorder caused by inheritable mutations in the gene SLC2A1. All known mutations reduce the function of Glut1 in the blood brain barrier and thus limit brain glucose availability. As the cerebral metabolic rate for glucose increases during infancy, patients become gradually symptomatic, a phenomenon that underscores the importance of early diagnosis via lumbar puncture and treatment, which has meet with some success in ameliorating several --but not all-- features of the disease. CONCLUSION: The increasing number of mild phenotypic variants being described, owing to the improved awareness of the disease, has led to the consideration of Glut1 deficiency in the diagnosis of infantile seizures, mental retardation, familial epilepsy and movement disorders.

Animals↗
PubMedDate not supplied

[Epidemiological study of onchocercosis in 5 villages of the valley of the Sanaga (Cameroon)].

The study carried out in five villages in the Sanaga Valley of Cameroon was concerned with the prevalence of the disease, the level of infection and an evaluation of the effect of the parasites on the health of the people. Entomological data were also collected. The study was concerned with the onchocerciasis found in the forest area where the disease is hyperendemic. The males are infected moreoften than the females. Among the adults the skin and lymphatic lesions are extremly important. It was found that as the visual acuity diminishes with age, from age forty many for the people are blind. The villages most affected are those situated near the Sanaga rapids where there is a concentration of the breeding sites of the vectors.

Adolescent↗
PubMedDate not supplied

Prospective, randomized comparison of disposable and reusable biopsy forceps in gastrointestinal endoscopy.

We prospectively compared biopsy specimens obtained with reusable and disposable stainless steel biopsy forceps of varying sizes and configurations. Six types of forceps were used: (1) jumbo reusable forceps, (2) jumbo disposable forceps with a Teflon sheath, (3) regular reusable forceps, (4) regular disposable forceps with a Teflon sheath, (5) regular long-jaw disposable forceps, and 6) regular long-jaw disposable forceps with a Teflon sheath. "Jumbo" forceps were those requiring an endoscopic biopsy channel of at least 3.3 mm. "Regular" forceps were those requiring only a 2.8-mm channel. Two biopsy specimens were obtained with each of the six forceps from normal-appearing stomach, duodenum, and sigmoid colon (25 sets at each location). Mixed and coded specimens were scored by a single pathologist for volume (height, width, and length) and histologic depth. Reusable and disposable jumbo forceps yielded biopsy specimens of similar volumes (30 +/- 1 mm3 and 33 +/- 1 mm3, respectively) and histologic depth (grades of 3.3 +/- 0.1 and 3.5 +/- 0.1, respectively). In comparison, the regular-sized biopsy forceps gave specimens with half the volume of those obtained by the jumbo forceps (reusable, 13 +/- 1 mm3; disposable with Teflon sheath, 15 +/- 1 mm3; long-jaw, 16 +/- 1 mm2; and long-jaw with Teflon sheath, 17 +/- 1 mm3). However, the histologic depths of specimens obtained with the regular disposable forceps were the same as those of specimens obtained with the jumbo forceps. Regular reusable biopsy forceps yielded specimens with the smallest overall volume and histologic depth. We conclude that disposable forceps are equivalent to reusable forceps and that the two types can be used interchangeably in gastrointestinal endoscopy. We recommend the use of jumbo forceps whenever possible because they provide biopsy specimens that are double the size of those obtained with regular forceps.

Biopsy↗