Search PubMed⌕ Search

Biomedical subjects

J He

Publications and source records attributed to J He.

At least 397 records · Page 22Linked to original sources
PubMed1993

Infectious bursal disease virus structural proteins expressed in a baculovirus recombinant confer protection in chickens.

Plasmids were prepared that contained cDNA segments of the large genomic segment A of infectious bursal disease virus (IBDV) strain GLS-5. The genes encoding the IBDV structural proteins (VP2, VP3 and VP4) were introduced into the baculovirus transfer vector pBlueBacI to obtain a recombinant baculovirus vIBD-7. When insect cells were infected with recombinant viruses, the result was synthesis of IBDV precursor proteins which were processed by the viral protease. The recombinant IBDV antigens were characterized by immunoprecipitation with monoclonal antibodies (MAbs) and polyclonal antiserum to IBDV, and by antigen-capture ELISA using a panel of IBDV-specific MAbs. The recombinant IBDV antigens closely resembled the native IBDV proteins and reacted with all the GLS-5 strain-specific neutralizing MAbs that recognize only conformational epitopes of IBDV. When susceptible chickens were inoculated with the recombinant IBDV antigens, virus-neutralizing antibodies were induced that conferred up to 79% protection against IBDV challenge.

Animals↗
PubMed1993

Expression and diagnostic utility of hepatitis E virus putative structural proteins expressed in insect cells.

The full-length putative structural proteins encoded by open reading frame 2 (ORF2) and ORF3 of hepatitis E virus have been cloned and expressed in recombinant baculovirus. Sera obtained from 28 Sudanese pediatric patients with acute hepatitis and 19 pediatric control patients were analyzed for reactivity to hepatitis E virus by using the baculovirus-expressed ORF2 and ORF3 proteins in a Western blot (immunoblot) format. Seventeen of the 18 patients classified as having non-A, non-B hepatitis, without acute antibody markers for hepatitis A, B, or C viruses, Epstein-Barr virus, or cytomegalovirus, were shown to have immunoglobulin M (IgM) antibodies to the recombinant ORF2 protein, as did two patients with chronic hepatitis B, three of seven patients with acute hepatitis A, and one patient with acute hepatitis B. None of the 19 control patients had IgM antibodies against the ORF2 or ORF3 proteins. The Western blot assay using the baculovirus-expressed ORF3 protein did not appear to be as sensitive as the assay based on the ORF2 protein. Only 10 of the patients classified as having non-A, non-B hepatitis had IgM antibodies to the baculovirus-expressed ORF3 protein. We conclude that a Western blot assay which uses a baculovirus-expressed ORF2 protein is both sensitive and specific for diagnosing acute hepatitis E.

Acute Disease↗
PubMed1993

Effect of captopril on fluctuations of blood pressure and renal blood flow in rats.

Arterial blood pressure and renal blood flow (RBF) fluctuations in rats were studied by autoregressive (AR) and autoregressive-moving average (ARMA) modeling. These estimation procedures provided greater sensitivity and frequency resolution than classic fast Fourier transform (FFT)-based methods and also require shorter observation periods. We estimated the transfer function of RBF autoregulation to test whether inhibition of angiotensin-converting enzyme impairs whole kidney dynamic autoregulation. The transfer function in control animals measured with the ARMA method was similar to transfer functions obtained previously, using FFT methods. Because of better frequency resolution, we also detected an oscillation in RBF at 50 mHz, the same frequency as an oscillation in tubular pressure and glomerular filtration rate that had been attributed to tubuloglomerular feedback (TGF), but that FFT methods had not previously found in whole kidney blood flow. Captopril increased the amplitude of RBF fluctuations and increased the gain of the transfer function at frequencies below 100 mHz, a frequency bandwidth previously associated with TGF. The increased gain indicates that TGF operates less effectively to mediate dynamic autoregulation when angiotensin conversion is inhibited. Gain at frequencies greater than 100 mHz, previously ascribed to the myogenic mechanism, was not affected by captopril. These results show that angiotensin, by modulating TGF, reduces fluctuations of RBF about the mean value.

Animals↗
PubMed1993

Analysis of parameters for epidural spinal cord stimulation. 3. Topographical distribution of paresthesiae--a preliminary analysis of 266 combinations with contacts implanted in the midcervical and midthoracic vertebral levels.

As a part of the systematic analysis of parameters involved in electrical epidural spinal cord stimulation therapy, distribution of paresthesiae in accordance with the position of contacts, as related to midline and vertebral level of contacts, was investigated. A preliminary analysis performed for 266 combinations having contacts implanted in the midcervical and low-thoracic vertebral levels showed that the topographical spread of the paresthesiae did not always cover the classical dermatomes. Significant paresthesiae spread was found as follows: C4-midline, unipolar combinations; the hand, forearm and upperarm, bipolar combinations; the hand, forearm; C4-lateral, unipolar combinations: the anterior shoulder, forearm, upper arm and hand, bipolar combinations: the hand, forearm and upper arm; T10-midline, unipolar combinations: the anterior and posterior of thigh, leg, knee, ankle and foot, bipolar combinations: the anterior and posterior thigh, leg, knee and foot; T10-lateral, unipolar combinations: the abdomen, anterior leg, knee and anterior thigh, bipolar combinations: the anterior thigh, anterior leg, knee and foot. This preliminary analysis suggests that more detailed studies would be worthwhile in the investigation of sensory responses to electrical stimulation of the spinal cord with epidural electrodes. Findings from such investigations could also be useful to extend our present anatomical knowledge of central and peripheral sensory neural structures.

Cervical Vertebrae↗
PubMed1993

Alcohol use and blood pressure in an unacculturated society.

Alcohol intake has been associated with higher blood pressure in acculturated populations but not in unacculturated societies. We performed a cross-sectional survey of a random community sample of 5023 male Yi rural farmers and 1656 Yi and 2173 Han men living in an urban setting. Average alcohol intake among drinkers was 36.4 g/d in Yi farmers, 56.5 g/d in Yi migrants, and 38.7 g/d in Han men. Age-adjusted mean diastolic blood pressure was 66.9, 70.5, and 71.7 mm Hg, respectively. Diastolic blood pressure was higher at higher alcohol intakes in all three groups (all P < .001). After adjustment for age, body mass index, heart rate, smoking, and physical activity, the change (95% confidence interval) in diastolic blood pressure for each standard drink was 0.50 (0.38-0.62), 0.31 (0.18-0.43), and 0.24 (0.07-0.40) mm Hg for Yi farmers, Yi migrants, and Han men, respectively. The percentage of variance in diastolic blood pressure explained by alcohol intake was 5% for Yi farmers, 4% for Yi migrants, and 2% for Han men. In a random sample of 831 men, these associations were independent of urinary sodium, potassium, calcium, and magnesium and sodium-potassium ratio. In the Yi farmers, associations were less strong for systolic blood pressure and no longer significant after adjustment. Approximately 33% of hypertension could be attributed to daily alcohol use in the Yi groups compared with 9.5% in the Han people.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Direct injection analysis of atenolol enantiomers in plasma using an achiral/chiral coupled column HPLC system.

A novel HPLC system was developed with an achiral/chiral coupled column for the direct injection analysis of atenolol (AT) enantiomers in plasma. The system consists of a size-exclusion column, an ODS silica column and a newly developed beta-cyclodextrin perphenylcarbamate(ph-beta-CD)-bonded silica column connected in a series via two switching valves. The neat plasma sample was directly injected onto the size-exclusion column, and the deproteinized fraction of AT enantiomers was concentrated on the ODS silica column. The enantiomers were then transferred and separated mutually on the ph-beta-CD silica column. The calibration line for each of the AT enantiomers was linear in the range of plasma concentration of 10-200 ng/ml (r > 0.9997) with good reproducibility (CV < 9.7%, n = 20). The recoveries from plasma were almost complete (> 97.4%) for both enantiomers. One analysis finished within 30 min. The developed system was applied to the enantioselective determination of plasma concentration-time curve of AT after the oral administration of racemic AT to a healthy volunteer.

Atenolol↗
PubMed1993

The long-term observation of the transplantation of encapsulated rat islets to the diabetic mice.

Rat islets encapsulated in the immuno-isolated membrane were transplanted intraperitoneally into 11 streptozotocin induced diabetic mice. The effective rate was 91% while all rejected in the 11 nonencapsulated xenograft group. 4 mice showed complete remission and longest normoglycemic period in those mice was 360 days. The pathological changes of islets of the long-term successful xenograft group were studied and showed atrophy. It proved that the immuno-isolated membrane can protect rejection during xeno-transplantation.

Alginates↗
PubMed1993

Mapping of sensory responses to epidural stimulation of the intraspinal neural structures in man.

A database is presented of sensory responses to electrical stimulation of the dorsal neural structures at various spine levels in 106 subjects subjected to epidural spinal cord stimulation. All patients were implanted for chronic pain management and were able to perceive stimulation in the area of pain. All patients entered in this study were able to reliably report their stimulation pattern. Several patients were implanted with more than one electrode array. The electrode arrays were placed in the dorsal epidural space at levels between C-1 and L-1. The structures that were likely involved include the dorsal roots, dorsal root entry zone, dorsal horn, and dorsal columns. At the present time, exact characterization of the structure being stimulated is possible only in limited instances. Various body areas are presented with the correspondent spine levels where implanted electrodes generate paresthesias. Areas that are relatively easy targets for stimulation are the median aspect of the hand, the abdominal wall, the anterior aspect of the thigh, and the foot. Some areas are particularly difficult to cover with stimulation-induced paresthesias; these include the C-2 distribution, the neck, the low back, and the perineum.

Abdominal Muscles↗
PubMed1993

[Effect of SC1001-sodium on ADA activity of the thymus, spleen and brain in repeated seizure rats].

Twenty nine adult SD rats in the experiment were randomly separated into two groups. Nineteen rats of them were intramuscularly injected (i.m.) with Coriaria lactone (CL, 2.5 mg/kg for female rat; 30 mg/kg for male rat) two days a time, continued 28 times, to induce repeated seizures, as the experimental group. The control group (n = 10) was injected with normal saline (N.S.) in the same volume as that of CL. The rats of experimental group were subdivided into a treatment group (n = 9) with SC1001Na (200 mg/kg) and a placebo group (n = 10) receiving N.S. in the same volume as that of SC1001 Na. All rats of repeated seizure were administered once every day for a week. The results indicated that SC1001Na (200 mg/kg) could inhibit in some degree the growth of immune organs (spleen and thymus) and significantly decrease the ADA activity of thymus, cerebrum and cerebellum, suggesting that the antiepileptic mechanism of SC1001Na is probably related with the decreased activity of ADA and the increased adenosine level in brain.

Adenosine Deaminase↗
PubMed1993

[Gas chromatographic analysis of nicotine in indoor air].

An analytical method for the determination of nicotine in indoor air was developed. Air sample was collected in absorption solution of 1% NaHSO4. After alkalization and heptance extraction, the content of nicotine in the sample was determined by gas chromatography with FID. The average sampling efficiency was 93.6%. The recovery rate was 89.3%-105.5% (mean = 98.4%). The coefficient of variation was 1.7-4.1%. Under the sampling condition the detection limit was 0.01 microgram/m3. After discussing the stability and extraction efficiency of the sample, we found the air sample collected in the absorption solution was stable for at least 7 days in refrigerator. The field experimental results show that the method is simple, reliable and suitable for collecting and determining trace nicotine in indoor air.

Air Pollution, Indoor↗
PubMed1993

[The multi-channel VEPs topography in optic neuritis].

The multi-channel VEPs topographies of 20 normal persons and 22 patients suffered from optic neuritis were recorded. In normal subjects, the topography showed symmetric distribution by full-field stimulation and paradoxical lateralization by half-field stimulation. In patients with optic neuritis, it showed asymmetric distribution most on the temperal side, some on the nasal side and occasionally in the middle by full-field stimulation. The result suggests that the optic nerve may be damaged on either temperal or nasal. The effect of the early diagnosis and evaluating treatment using topography is also discussed.

Adult↗
PubMed1993

[Preconcentration of trace Fe, Mn, Cu and Cd in water with charcoal and determination by flame atomic absorption spectroscopy].

The absorption of Fe, Mn, Cu and Cd by charcoal and the influence of pH, particle size and temperature on absorption were studied. A method for the preconcentration of these irons in water was established, and with flame atomic absorption spectroscopy a content as low as microgram/L could be determined. The recovery and the coefficient of variance (n = 6) were in the range of 90-113% and 2.6-9.9%, respectively. The proposed method is simple, rapid, accurate reproducible and suitable for the preconcentration and determination of titled metal irons in different kinds of water.

Cadmium↗
PubMed1993

A study on the clinical effect and immunological mechanism in the treatment of Hashimoto's thyroiditis by moxibustion.

71 cases of Hashimoto's thyroiditis were treated by moxibustion and their immune function and thyroid function were observed. It was found that moxibustion was able to reduce the thyroid antibodies in the peripheral blood of the patients with hypothyroidism and to recover their thyroid function. It was also found that moxibustion could lower the thyroid antibody secretory levels and ADCC (antibody-dependent cell-mediated cytotoxicity) activities of the lymphocytes. In addition, the action of moxibustion in reducing the secretion of thyroid antibodies was related to its action of regulating the proportions of T lymphocyte subsets. The results indicate that the treatment of Hashimoto's thyroiditis by moxibustion is probably accomplished through its effect in regulating the relationship among the T lymphocyte subsets.

Adult↗
PubMed1992

Valinomycin modifies phosphorescence quenching in cytochrome c oxidase.

The spectrum of resting cytochrome c oxidase is modulated by valinomycin addition, which induces a red shift of the Soret band. The enzyme is known both to fluoresce and phosphorescence, effects which can be modulated by certain protein reagents and quenchers. Valinomycin had little effect upon fluorescence at 335 nm, whether excited at 295 nm or 280 nm (tryptophans or both tryptophans and tyrosines, respectively). Phosphorescence at 445 nm was slightly enhanced upon the binding of valinomycin to the enzyme, suggesting a small conformational change accompanying the spectral shift of the heme groups. The quenching by nitrite of the phosphorescence excited at 260 nm, but not that excited at 295 nm, was diminished by valinomycin. This suggests that the valinomycin-induced conformational change may involve (i) a change in the accessibility of tyrosines to the quencher and/or (ii) a change in distribution of distances and/or orientations between populations of tyrosines and tryptophans.

Animals↗
PubMed1992

Biopathologic characteristics of DNA content in crypt cells of transitional mucosa adjacent to carcinomas of the rectum and rectosigmoid.

The transitional mucosa (TM) adjacent to carcinomas of the large bowel shows histologic and mucin histochemical changes that may indicate premalignant change and may be of prognostic value after radical resection. In this study, 10 anterior resection specimens from patients with carcinomas of the rectum and rectosigmoid were used to compare the nuclear DNA content in TM with those in cancer tissue and with those in nontransitional mucosa (N-TM; i.e., uninvolved mucosa remote from tumors showing normal histologic and mucin histochemical features). The nuclear DNA content was assessed using DNA image cytometry on Feulgen-stained sections. As compared with N-TM, crypts in TM contained greater numbers of cells, were elongated, and were more likely to be branched with marked sialomucin secretion, accompanied by a marked reduction in the normal sulfomucin content. The mean nuclear DNA content in the upper, middle, and lower thirds of crypts was significantly higher in TM than in N-TM, and the nuclear DNA content in TM exhibited no correlation to that in tumors. The results suggest that TM adjacent to carcinomas of the rectum and rectosigmoid has higher proliferative activity, providing further evidence that TM may be an unstable premalignant change.

Adenocarcinoma↗
PubMed1992

Direct injection analysis of carbamazepine and its active 10,11-epoxide metabolite in plasma by use of a semipermeable surface (SPS) silica column in LC.

A semipermeable surface (SPS) silica column was applied for the simultaneous determination of carbamazepine (CBZ) and its active 10,11-epoxide metabolite (EPO) in plasma following direct injection in LC. The SPS packing material consists of an ODS ligand as the hydrophobic inner phase and a polyoxyethylene network as the hydrophilic outer phase. When a 5-microliters portion of intact plasma was injected onto the column using a mobile phase of phosphate buffer (pH 7.1, ionic strength 0.1)-acetonitrile (4:1, v/v), the plasma proteins were size-excluded, whereas the drug and its metabolite were retained and separated both from each other and from other commonly co-administered drugs such as phenobarbital (PB) and phenytoin (DPH). The calibration graphs (peak area vs concentration) of CBZ, EPO and PB were linear over the therapeutic range of plasma concentration (r greater than 0.998) with good relative standard deviations (RSD less than 3.98%, n = 5). The recoveries from plasma were almost complete (greater than 96.6%). The analysis time was 17 min. The method as developed was applied in studies on the time course of plasma concentrations of unchanged CBZ and EPO after i.v. administration of CBZ to the rat.

Calibration↗