Biomedical subjects

Y M Luo

Publications and source records attributed to Y M Luo.

45 records · Page 3Linked to original sources

PubMed1998

Diaphragm EMG measured by cervical magnetic and electrical phrenic nerve stimulation.

The purpose of the study was to compare electrical stimulation (ES) and cervical magnetic stimulation (CMS) of the phrenic nerves for the measurement of the diaphragm compound muscle action potential (CMAP) and phrenic nerve conduction time. A specially designed esophageal catheter with three pairs of electrodes was used, with control of electrode positioning in 10 normal subjects. Pair A and pair B were close to the diaphragm (pair A lower than pair B); pair C was positioned 10 cm above the diaphragm to detect the electromyogram from extradiaphragmatic muscles. Electromyograms were also recorded from upper and lower chest wall surface electrodes. The shape of the CMAP measured with CMS (CMS-CMAP) usually differed from that of the CMAP measured with ES (ES-CMAP). Moreover, the latency of the CMS-CMAP from pair B (5.3 +/- 0.4 ms) was significantly shorter than that from pair A (7.1 +/- 0.7 ms). The amplitude of the CMS-CMAP (1.00 +/- 0.15 mV) was much higher than that of ES-CMAP (0.26 +/- 0.15 mV) when recorded from pair C. Good-quality CMS-CMAPs could be recorded in some subjects from an electrode positioned very low in the esophagus. The differences between ES-CMAP and CMS-CMAP recorded either from esophageal or chest wall electrodes make CMS unreliable for the measurement of phrenic nerve conduction time.

Action Potentials↗

PubMed1993

Effects of ginseng root saponins and ginsenoside Rb1 on immunity in cold water swim stress mice and rats.

The proliferation of splenic lymphocytes, the humoral immune response to sheep red blood cells, and the phagocytotic function of intraperitoneal macrophages were all suppressed by cold water (4 degrees C) swim stress (CWSS) for 5 min in rats and for 3 min in mice. Meanwhile, the levels of serum corticosterone increased. Ginseng root saponins 100 mg.kg-1 or ginsenoside Rb1 10 mg.kg-1 ip or ig completely antagonized the immunosuppression induced by CWSS, and inhibited the increase of serum corticosterone in CWSS rats, but increased the level of serum corticosterone further in CWSS mice.

Animals↗

PubMed1991

Spleen cell dialyzable extracts (SCDE) mediated immunotherapy for patients with myasthenia gravis.

We studied 14 cases of myasthenia gravis (MG) with regard to their anti-acetylcholine receptor antibody (AChR-Ab) production, peripheral blood CD4+/CD8+ ratio, and responses of peripheral lymphocytes to PHA and PWM stimulations. We found that the clinical severity was not proportional to AChR-Ab level in serum in terms of whole myasthenic population, whereas in one individual patient there was a close correlation between clinical severity and the AChR-Ab level in serum. The CD4+/CD8+ ratio in myasthenic patients was significantly higher than that of normal controls. The responses of T- and B-cells to mitogenic stimulations were impaired in myasthenic patients. The immune abnormalities found in the majority of the patients were restored to about normal after spleen cell dialyzable extracts (SCDE) therapy was applied to all patients. The results implicated that SCDE, working as an immunomodulator, could serve as a promising agent to normalize the abnormal immune functions of MG patients or other autoimmune diseases.

Adjuvants, Immunologic↗

PubMed1991

Alloantibodies against donor epidermis and early kidney transplant rejection.

We have previously observed that transplant recipient sera with endothelial antibodies are bound to epidermal cells, as shown by immunofluorescence on sections of skin. It was also reported that early kidney failures that occurred despite negative T cell crossmatches were associated with, and could have been predicted by, a crossmatch with donor skin. Ninety patients undergoing kidney transplantation have now been evaluated using this technique. A few other patients were excluded from the analysis because of the presence of autoantibodies staining autologous skin. In 12 the crossmatch with donor skin was positive, and 9 of them had severe rejection within the first 10 days after transplantation. The three patients with a positive skin crossmatch and a benign course had not been tested with autologous skin and therefore autoantibodies could not be excluded. Only 7 of the 78 patients with negative skin crossmatches had early rejection. The correlation between skin crossmatch and early rejection was statistically highly significant (P less than 0.0001). Studies by flow cytometry have shown that these antigens are found on the surface of epidermal and endothelial cells, and are modulated by gamma interferon. When tested against a panel of skin donors, skin alloantibodies gave different patterns of positive and negative reactions, suggesting polymorphism.

Antigens, Surface↗

PubMed1990

The cluster diathesis.

We present further evidence for a sympathetic defect of vasomotor control of the anterior cerebral artery (ACA) on the side of the headache during cluster periods. In 119 cluster headache patients, utilizing transcranial Doppler, we measured CO2 reactivity of the major intracranial vessels, in and out of cluster. Reactivity was significantly lower during the cluster period, but only in the ACA on the side of the headache. Nineteen patients followed sequentially for a full cycle (ie/both in and out of a cluster period) showed the same changes. In 3 out of 6 patients in an active cluster period, we describe a lesion on Gallium single-photon emission computerized tomography (SPECT) in the region of the cavernous sinus which fades as the patient moves out of cluster. It is felt that this lesion may represent the cavernous sinus plexus lesion postulated as the central lesion in cluster. Changes in the sympathetic outflow at this point could explain the changes we have described in ACA CO2 reactivity during cluster.

Adult↗

PubMedDate not supplied

Survival of faecal coliforms and hygiene risks in soils treated with municipal sewage sludges.

An incubation experiment was conducted to monitor effect of sewage sludge application on changes in numbers of faecal coliforms in soils over time after sludge application and evaluate the hygiene risks. Soil faecal coliform counts were made after 1, 7, 14, 28, 56 and 84 days of incubation. The faecal coliform counts in the sludge-treated soils decreased substantially with time and were similar to those in the untreated controls after incubation for 56 days. Land application of air-dried sludges increased the hygiene risks due to the re-growth of faecal coliforms, and the counts of faecal coliforms in soil treated with air dried sludge from Suzhou (91% DM) were 50 times higher than in soils with fresh dewatered sludge from Suzhou (15% DM) after 7 days of incubation. The main factors affecting the changes in faecal coliform counts were sludge type and incubation time. Sludge type determined the faecal coliform counts and the ability of the faecal coliforms to re-establish, and indigenous microorganisms competed with the faecal coliforms for nutrients during the incubation process.

Animals↗

PubMedDate not supplied

Degradation of benzo[a]pyrene in soil with arbuscular mycorrhizal alfalfa.

Mycorrhizal and non-mycorrhizal alfalfa (Medicago sativa) was grown in pots containing soil artificially contaminated with various levels of benzo[a]pyrene (B[a]P) (0, 1, 10 and 100 mg kg(-1)). Soil and plants were sampled after 30, 40, 50, 60 and 90 days and compared with unlanted pots. The percentage of mycorrhizal root length colonized by Glomus caledoniun was not significantly affected by the addition of B[a]P up to 10 mg kg(-1) but was significantly lower at 100 mg kg(-1)B[a]P compared with low concentrations (p < 0.05). There was no difference in soil polyphenol oxidase and dehydrogenase activity among the controls and applications of 1 and 10 mg kg(-1) of B[a]P. However, enzyme activities were significantly higher at 100 mg kg(-1) B[a]P compared with the other three treatments, and there was no mycorrhizal effect. Over a period of 90 days the concentration of B[a]P in soil in which alfalfa was grown was significantly lower than in unplanted soil (p < 0.05). Degradation rates of B[a]P added at 1, 10 and 100 mg kg(-1) without G. caledonium were 76, 78 and 53%, and with mycorrhizal inoculation were 86, 87 and 57%. The degradation rate in unplanted soil was significantly lower than in planted soil, and was significantly higher in medium- and low-B[a]P treatments than in the high B[a]P concentration tested. There is a possibility of enhancement phytoremediation of PAHs in rhizosphere soil with arbuscular mycorrhizal fungi.

Benzo(a)pyrene↗

PubMedDate not supplied

Effects of cadmium on nutrient uptake and translocation by Indian Mustard.

Plants that hyperaccumulate metals are ideal subjects for studying the mechanisms of metal and mineral nutrient uptake in the plant kingdom. Indian Mustard (Brassica juncea) has been shown to accumulate moderate levels of Cd, Pb, Cr, Ni, Zn, and Cu. In this experiment, 10 levels of Cd concentration treatments were imposed by adding 10-190 mg Cd kg(-1) to the soils as cadmium nitrate [Cd(NO3)2]. The effect of Cd on phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and the micronutrients iron (Fe), manganese (Mn), copper (Cu), and zinc (Zn) in B. juncea was studied. Plant growth was affected negatively by Cd, root biomass decreased significantly at 170 mg Cd kg(-1) dry weight soils treatment. Cadmium accumulation both in shoots and roots increased with increasing soil Cd treatments. The highest concentration of Cd was up to 300 mg kg(-1) d.w. in the roots and 160 mg kg(-1) d.w. in the shoots. The nutrients mainly affected by Cd were P, K, Ca, Fe, and Zn in the roots, and P, K, Ca, and Cu in the shoots. K and P concentrations in roots increased significantly when Cd was added at 170 mg kg(-1), and this was almost the same level at which root growth was inhibited. Zn concentrations in roots decreased significantly when added Cd concentration was increased from 50 to 110 mg kg(-1), then remained constant with Cd treatments from 110 to 190 mg kg(-1). However, Zn concentrations in the shoots seemed less affected by Cd. It is possible that Zn uptake was affected by the Cd but not the translocation of Zn within the plant. Ca and Mg accumulation in roots and shoots showed similar trends. This result indicates that Ca and Mg uptake is a non-specific process.

Biodegradation, Environmental↗

PubMedDate not supplied

Nutrients can enhance phytoremediation of copper-polluted soil by Indian mustard.

An orthogonally designed experiment was conducted to study the single and combined effects of N, P and K on phytoremediation of Cu-polluted soil by Indian mustard. Addition of fertilizer N and P significantly increased Indian mustard shoot yield. Two high treatments combined with N resulted in the highest yields, followed by low-P combined with N. In contrast, high P with no N gave no yield increase and K had no effect on yield of Indian mustard. Nitrogen and P increased the amount of chlorophyll in the leaves, indicating that the yield increases were due to enhanced photosynthesis. Nitrogen application had no effect on plant Cu concentrations but addition of P slightly decreased plant Cu concentrations, likely a dilution effect resulting from the increase in yield. Among the treatments, N and P applied at 100 and 200 mg kg(-1) respectively with no K application resulted in the highest Cu uptake. Thus, a combination of low N and high P produced a yield increase in Indian mustard that was more than adequate to compensate for a slight decrease in Cu concentration, resulting in the highest Cu removal from the contaminated soil.

Biodegradation, Environmental↗