A simulation study on +Gz protection afforded by extended coverage anti-G suits

Computer simulation studies using our newly developed mathematical model of human cardiovascular (CV) system were performed to investigate the effect of bladder coverage and inflation schedule of anti-G suit on G protection and CV response. The simulation results agree well with centrifuge experiments. The study demonstrates that additional +Gz protection provided by the extension of the bladder coverage depends mainly upon the pressure transmission efficiency to the underlying tissues and vessels. Although G tolerance increases clearly with the increase of suit inflation schedule, the tendency of increase seems slower when inflation schedule becomes higher than 10 kPa/G.

Design and development of an interactive medical teleconsultation system over the World Wide Web

The objective of the medical teleconsultation system presented in this paper is to demonstrate the use of the World Wide Web (WWW) for telemedicine and interactive medical information exchange. The system, which is developed based on Java, could provide several basic Java tools to fulfill the requirements of medical applications, including a file manager, data tool, bulletin board, and digital audio tool. The digital audio tool uses point-to-point structure to enable two physicians to communicate directly through voice. The others use multipoint structure. The file manager manages the medical images stored in the WWW information server, which come from a hospital database. The data tool supports cooperative operations on the medical data between the participating physicians. The bulletin board enables the users to discuss special cases by writing text on the board, send their personal or group diagnostic reports on the cases, and reorganize the reports and store them in its report file for later use. The system provides a hardware-independent platform for physicians to interact with one another as well as to access medical information over the WWW.

Experimental model of renovascular hypertension

OBJECTIVE

To establish a model of renovascular hypertension.

METHODS

A 4/0 resorbable chromic catgut ligature was used to ligate subtotally the renal arteries of 18 dogs, forming experimental renovascular hypertension steadily. Blood pressure, plasma renin activity, the ultrastructural changes of juxtaglomerular apparatus and renal artery wall were studied after the constriction.

RESULTS

It was reasonable that renal blood flow measured with an electromagnetic flowmeter was reduced by 30% after the constriction. The pathological changes of the induced renal artery stenosis were similar to those of fibromuscular dysphasia.

CONCLUSION

The findings provide valuable evidence for the treatment of renovascular hypertension.

Optimization and mechanism of step-leap respiration exercise in treating of cor pulmonale

The interaction between cardiovascular system and the respiratory system is complicated and may be used for the rehabilitation of the cor pulmonale disease. To study the effects of different breathing mode on the cardiac and pulmonary systems, a mathematical model is established based on the previous work. Using this model, computer simulation experiments are carried out for searching an optimal respiration mode in treating of cor pulmonale disease. Results indicate that the step-leap respiration mode could provide a better assistant to the rehabilitation of the cor pulmonale patients in the sense of increasing coronary flow, reducing pulmonary arterial pressure and reducing the working load for the right heart. This result is also proven by the clinical experiments. This work may suggest that a proper directed respiration exercise can be used in the treatment of cor pulmonale disease.

[The studies on MTS1/p16 gene deletion during transformation of human bronchial epithelial cells]

OBJECTIVE

To detect the deletion of MTS1/p16 and the expression of P16 protein during the transformation of human bronchial epithelial cell line M.

METHODS

Dual-color fluo-rescence in situ hybridization (FISH), immunohistochemical staining and western blot analysis were carried out.

RESULTS

No deletion of MTS1/p16 gene was found in MP18 cells of the cell line M. But partial deletions occurred in the MP36 and MP120 cells of the cell line M. Immunohistochemical analysis and western blot test showed lower expression of P16 protein in the MP120 cells than in MP20 cells.

CONCLUSIONS

MTS1/p16 gene deletion contributes to the malignant transformation of the human bronchial epithelial cell line M. Also FISH is a useful technique in detecting gene deletion.

[Effects of the glucoprotein component of musk on functions of rat polymorphonuclear leukocytes activated by LTB4 in vitro]

To investigate the effects of musk-1, a glucoprotein component isolated from the water extract of musk, on some functions of rat polymorphonuclear leukocytes activated by LTB4, an in vitro incubation system with rat polymorphonuclear leukocytes was used. The superoxide anion production was determined by cytochrome C reduction, and the beta-glucuronidase and lysozyme release was quantitated by enzyme reactions in which phenolphthaleinglucuronic acid and micrococcus lysodeikticus were used as the substrates. In comparison with the control, musk-1 at final concentrations of 1 microgram/ml-100 micrograms/ml can increase the superoxide anion production by 28.7%-202.1% and decrease the beta-glucuronidase and lysozyme release by 3%-46% and 6%-32% respectively in rat polymorphonuclear leukocytes. It is concluded that musk-1 can significantly affect the functions of rat polymorphonuclear leukocytes activated by LTB4. One of the mechanisms of this anti-inflammatory action of musk may consist in the inhibition of lysosomal enzyme release.

[An internet based medical communication server]

The telemedicine and medical conference usually need multi-point to multi-point communication. Because the communication users can be patients, specialists or medical centers, they have different communication ratios and different physical connection, therefore, this kind of communication is complicated and limited by the communication ratios. In this paper, to meet the requirements of medical communication, we presented a concept of medical communication server which is able to receive data packages and deliver them according to the request of clients, and described its implementation in Windows 95 environment by using Windows Sockets.

The design and preliminary evaluation of a home electrocardiography and blood pressure monitoring network

A home electrocardiography (ECG) and blood pressure (BP) monitoring network was established in Beijing. The network consisted of three parts: (1) the home ECG and BP monitoring devices; (2) the monitoring centre at the hospital; and (3) the data communication network, for which we chose the public telephone network. The system was tested in our university hospital for two months with 30 patients and six normal volunteers. A preliminary evaluation by the users indicated that the system was acceptable in terms of its efficiency and effectiveness. This paper describes the system design, the preliminary testing procedure, and results.

Simulation study of the interaction between respiration and the cardiovascular system

Many studies have been done on the respiratory and the cardiovascular system. Among them, only a few are on the interaction of these two physiologic systems. To explore the mechanism of the integration of these two physiological systems, computer simulation has been done; we report the preliminary results obtained in our laboratory. In this study, a mathematical model of the cardiovascular system integrated with the respiratory mechanical system has been established. The model is based on our previous work on cardiovascular modeling. The previous lumped lung model has been replaced by a multielement model with more detail. Interthoracic and abdominal pressures and modeled as external pressure sources on the related cardiovascular elements. Using this model, a sequence of simulation studies have been carried out. Different respiratory modes have been simulated and the different effects are observed in the simulation results. The results indicate that by following a certain respiratory pattern, the circulation status can be improved. These results agree with clinical observations.

A communication server for telemedicine applications

The telemedicine applications, in some cases, need multipoint-to-multipoint communication. To meet the requirement of telemedicine communication, the development of a medical communication server is proposed in this paper. To make a working, as well as cost-effective, communication platform for the telemedicine applications, a specially designed communication server model is proposed in this work. This server is able to provide an effective multipoint-to-multipoint communication service for any level applications in telemedicine. The implementation program of this server is developed in a Windows'95 environment by using a winsocket. The trial application testing in a telemonitoring system is also presented to demonstrate the feasibility of taking such a structure with the server. By using the architecture of such a communication server in telemedicine applications, the multipoint-to-multipoint communication is easily managed and the communication processes are simplified and well controlled by the server.

Measurement of spontaneous transfer and transbilayer movement of BODIPY-labeled lipids in lipid vesicles

An assay was developed to study the spontaneous transfer and transbilayer movement (flip-flop) of lipid analogs labeled with the fluorescent fatty acid, 5-(5,7-dimethyl BODIPY)-1-pentanoic acid (C5-DMB-) in large unilamellar lipid vesicles comprised of 1-palmitoyl-2-oleoyl phosphatidylcholine (POPC). The assay is based on the concentration-dependent changes in fluorescence intensity that occur when donor vesicles containing a C5-DMB-lipid are mixed with nonfluorescent acceptor vesicles. A kinetic model was developed to describe the time-dependent changes in concentration of a lipid undergoing both spontaneous transfer between unilamellar vesicles and transbilayer movement within the vesicle membranes, and a mathematical solution was obtained. Data were obtained using C5-DMB-labeled analogs of sphingomyelin (C5-DMB-SM), ceramide (C5-DMB-Cer), phosphatidylcholine (C5-DMB-PC), and diacylglycerol (C5-DMB-DAG), and kinetic parameters for each lipid were determined using a nonlinear least-squares fitting program. The half-times for interbilayer transfer of the lipids were C5-DMB-SM (21 s) < C5-DMB-PC (350 s) approximately C5-DMB-Cer (400 s) << C5-DMB-DAG (100 h). C5-DMB-Cer (t1/2 approximately 22 min) and C5-DMB-DAG (t1/2 approximately 70 ms) exhibited rapid spontaneous transbilayer movement, while C5-DMB-SM (t1/2 approximately 3.3 h) and C5-DMB-PC (t1/2 approximately 7.5 h) moved across the bilayer very slowly. These results provide a basis for interpreting the behavior of these lipid analogs in cells.

[The study of women's bone density in Beijing]

Bone mass of 434 healthy women aged from 20-65 years was measured at both distal and mid-radius of the non-dominant arm by using a single-photon absorptiometer (SPA) with an 241Am source (model SD-1000), and bone density and related factors were studied. The bone density in women reached the peak value around 40 years old and the bone loss began around 45 years old. Bone loss was accelerated after menopause, with faster speed in trabecular bone than in cortical bone. The effect of menopause on bone loss was more significant than the effect of advancing age. Among 174 menopausal women, 9.8% had fractures. The bone density of postmenopausal women with history of bone fracture was lower than that of those without fracture. The results of this study suggest that the measurement of bone density can be used to predict the risk of osteoporotic fractures.

[Effect of Salvia miltiorrhizae Composita on erythrocyte membrane phospholipid in patients with coronary heart disease]

OBJECTIVE

To investigate the function of phospholipid metabolism in pathogenesis of coronary heart disease (CHD) and the effect of Salvia miltiorrhizae Composita (SMC) on it.

METHODS

The levels of erythrocyte membrane phospholipid, blood lipid peroxide (LPO), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were determined in the patients with CHD by Thinlayer chromatography and fluorimetry during the treatment of SMC.

RESULTS

Sphingomyelins (SM), phosphatidyl serine (PS), phosphatidyl ethanolamine (PE) and lysophosphatide (LL) of erythrocyte membrane phospholipid were increased in patients with CHD. Phosphatidyl cholines (PC) was lower than control group. Among them, the ratios of SM/PC and PS/PC were significantly higher. In the patients with CHD, LPO was significantly increased and ratios of SOD/LPO and GSH-Px/LPO significantly decreased. After the treatment with SMC, LL, SM, PS and PE of erythrocyte phospholipid and the ratios of SM/PC and PS/PC and LPO were decreased. PC and SOD/LPO were increased.

CONCLUSIONS

The abnormality of erythrocyte membrane phospholipid participate the occurrence and development of CHD. SMC might improve the abnormality of erythrocyte phospholipid and lipid peroxide and possess the effect of regulating phospholipid metabolism.

[Effects of the glucoprotein component of musk on the functions of rat polymorphonuclear leukocytes activated by fMLP in vitro]

To investigate the effects of musk-1, a glucoprotein component isolated from the water extract of musk, on the release of superoxide anion as well as beta-glucuronidase and lysozyme of rat polymorphonuclear leukocytes activated by fMLP. An in vitro incubation system with rat polymorphonuclear leukocytes was used. Superoxide anion production was determined by cytochrome C reduction. beta-glucuronidase and lysozyme release was quantitated by enzyme reactions in which phenolphthaleinglucuronic acid and micrococcus lysodeikticus were as the substrates, respectively. In comparison with control, musk-1 at final concentrations of 1-100 micrograms/ml can increase superoxide anion production by 23.0%-83.6% and decrease beta-glucuronidase and lysozyme release by 7%-47% and 9%-22%, respectively, in rat polymorphonuclear leukocytes. It is concluded that Musk-1 can significantly affect the functions of rat polymorphonuclear leukocytes. Therefore, inhibition of lysosomal enzyme release might be considered as one of the mechanisms of anti-inflammatory role of musk.

[The effect of glucoprotein component of musk on arachidonic acid metabolizing enzymes in rat polymorphonuclear leukocytes]

To investigate the effects of musk-1, a glucoprotein component isolated from the water extract of musk, on arachidonic acid metabolizing enzymes, which include phospholipase A2(PLA2), 5-lipoxygenase (5-LO), and cyclooxygenase (COX), in rat polymorphonuclear leukocytes, an in vitro incubation system with rat polymorphonuclear leukocytes or homogenate supernatant of the same cells was used. In comparison with control, musk-1 at final concentrations of 1-100 micrograms/ml can increase AA release from PMNL by 6.0%-21.6%, decrease LTB4 biosynthesis in homogenate supernatant of the cells by 9%-81%, but increase 6-keto-PGF1 alpha production by 18.2%-85.4%.

[The monitoring of post cesarean section uterine scal with B-ultrasonographic and clinical detections]

OBJECTIVE

To find out an effective method for monitoring the healing of uterine incision after cesarean section.

METHODS

1,145 patients with cesarean section were monitored by B-ultrasonography. In 19 patients who revealed fluid mass in uterine incision, 10 cases were treated by percutaneous drainage under sonographic guidance and 9 cases as control.

RESULTS

According to sonographic characteristics, uterine incision healing can be divided into three conditions: normal type revealing a smooth strong echo's light band in uterine incision (93.97%), inflammatory type revealing an uneven parenchymatous light mass (3.67%), and fluid mass with inflammation revealing a complex light mass with low echo's or anechoic area (2.36%). There were abnormal clinical signs in most cases of inflammation. The percutaneous drainage therapy showed marked effect.

CONCLUSIONS

The monitoring of uterine incision healing by B-ultrasonography plays an important role in preventing late post-partum hemorrhage.

[A simulation study on G protection using tilt-back seat]

A mathematical model of human cardiovascular system with cardiopulmonary interaction was developed basing on the previous works of Jaron, Bai jing, et al (1988, 1992). The model of pulmonary circulation was improved and intrathoracic pressure, intra-abdominal pressure and pulmonary alveolar pressure were introduced in the new model. Computer simulation experiments using this model for human relaxed tolerance to rapid onset (1 G/s), gradual onset (0.1 G/s), and high onset (5 G/s) G exposures, at seat back angles of 13 degrees, 30 degrees, 45 degrees, 55 degrees, 65 degrees, 75 degrees, and 85 degrees, were performed. The simulation results are consistent with the experimental data obtained from reported centrifuge experiments. The tolerance increase by tilt back seat may be attributed to the following three factors: (1) decrease of retinal-aorta hydrostatic distance; (2)decrease of venous pooling in the lower body; (3)decrease of G onset rate in Z axis.

[Simulation study on the blood volume feedback control]

To describe the relationship between blood volume and the cardiac function mathematically, a computer cardiovascular model, was developed including a systemic circulation, a heart and a pulmonary model and a blood volume feedback control. Simulation results indicate that the chronic heart failure could be compensated by increasing the blood volume to maintain the proper arterial pressure. Deterioration in heart failure causes an increase in blood volume, as well as increases in heart volume and cardiac energy consumption. These results are in agreement with the clinical data and results reported in the literature. The simulation also shows that for a predetermined ventricular contractility, an adequate increase in blood volume will increase the heart volume but decrease the cardiac energy consumption and lead the heart to work in an optimum condition.

A home electrocardiography and blood pressure telemonitoring system

A home electrocardiography (ECG) and blood pressure telemonitoring system for cardiac patients was installed in the Macau region. The monitoring centre was established in the emergency unit at the Government Hospital of Macau. The first users were 10 cardiovascular patients selected by a physician. The average age of these users was 61 years (range 30-78). The results of a three-month trial showed that the system was easy to operate and technically reliable. It was found to be helpful for cardiac patients. The most significant problem during the trial was electrical noise from the ECG electrodes.

Unique long terminal repeat U3 sequences distinguish exogenous jaagsiekte sheep retroviruses associated with ovine pulmonary carcinoma from endogenous loci in the sheep genome

Ovine pulmonary carcinoma (OPC) is a contagious lung cancer of sheep that is presumed to be caused by an exogenous retrovirus of sheep, jaagsiekte sheep retrovirus (JSRV). The sheep genome carries 15 to 20 copies of endogenous sheep retrovirus (ESRV) loci that hybridize to JSRV DNA probes. In order to clarity the etiologic roles of ESRV and an exogenous JSRV-like retrovirus (exJSRV) in OPC, we assessed sequence differences between ESRV and JSRV. Molecular characterization of six ESRV loci revealed restriction sites specific for JSRV. Nucleotide sequences of ESRVs from sheep of different breeds were similar to those of JSRV in structural genes but divergent in U3. Therefore, primers specific for the U3 sequences of exJSRV were designed for use in the PCR. Of 13 tumor DNAs tested by PCR with these exogenous-virus U3 primers, 8 produced DNA fragments that hybridized with the JSRV gag probe, but neither lung DNAs from healthy sheep nor DNAs from nontumor tissues of diseased sheep produced similar DNA fragments. exJSRV PCR products from tumor DNAs of sheep with OPC from three continents had restriction profiles similar to each other but different from those of ESRVs upon digestion with EcoRI, HindIII, NdeI, KpnI, and ScaI. These exjSRVs could be classified into two genotypes according to U3 sequences and restriction profiles. U3 sequences of exJSRV proviruses in tumors strongly resembled those of JSRV but differed from those of ESRVs, suggesting that exJSRVs, rather than ESRVs, are primarily associated with oncogenesis in OPC.

The effects of intra-aortic balloon pumping combined with coronary sinus interventions on failing hearts: a model study

Cardiac energy balance is an important factor in evaluating cardiac function. In this work, the effects of different assist modalities and their combinations on cardiac energy balance and global cardiac function have been investigated. The simulation results indicate that coronary sinus interventions (CSIs) can provide myocardium with more energy than IABP when coronary arterial stenosis is serious. However, IABP can decrease myocardial energy consumption and enhance cardiac output, which cannot be done by CSIs, under the condition of impaired myocardial contractility. Therefore, we conclude that the combination of IABP and CSIs is the best way of assisting failing circulation.

Characterization of SDS--PAGE-separated proteins by matrix-assisted laser desorption/ionization mass spectrometry

A new strategy to characterize SDS--PAGE-separated proteins with MALDI MS is described. The proteins, electroblotted onto nitrocellulose after SDS--PAGE separation and stained with reversible Ponceau S dye, are readily recovered by dissolving the membrane in matrix solutions prepared with acetone. The resulting mixtures are amenable to direct MALDI MS analysis, which provides a rapid and accurate means of measuring the molecular weights of SDS--PAGE-separated proteins and of peptides that result from CNBr digestion of proteins on the nitrocellulose membrane. Compared with the traditional elution method, this procedure provides more efficient detection of proteins and peptides, especially the higher molecular weight proteins from the membrane. As little as 3.5 pmol of lysozyme and 15 pmol of bovine albumin loaded onto a gel can be detected using this method. The detection sensitivity is higher than or comparable to that of the traditional Coomassie Brilliant Blue staining procedure.

The exogenous form of Jaagsiekte retrovirus is specifically associated with a contagious lung cancer of sheep

Sheep pulmonary adenomatosis ([SPA] ovine pulmonary carcinoma) is a transmissible lung cancer of sheep that has been associated etiologically with a type D- and B-related retrovirus (jaagsiekte retrovirus (JSRV]). To date it has been impossible to cultivate JSRV in vitro and therefore to demonstrate the etiology of SPA by a classical approach. In addition, the presence of 15 to 20 copies of endogenous JSRV-related sequences (enJSRV) has hampered studies at the molecular level. The aim of this study was to investigate whether the expression of exogenous JSRV was specifically associated with neoplasia in SPA-affected animals. Initially, we found that enJSRVs were transcribed in a wide variety of normal sheep tissues. Then, by sequencing part of the gag gene of enJSRV we established a ScaI restriction site in gag as a molecular marker for the exogenous form of JSRV. Restriction enzyme digestion of PCR products obtained from the amplification of cDNA from a total of 65 tissues collected from SPA-affected and unaffected control sheep revealed that the exogenous form of JSRV was exclusively and consistently present in tumor tissues and lung secretions of the affected animals. In addition, exogenous JSRV provirus was detected only in DNA from SPA tumors and not from nontumor tissues of the same animals. This study has demonstrated clearly that the exogenous form of JSRV is specifically associated with SPA tumors.

Splenic hypofunction in cirrhosis is not associated with increased risk for infections

BACKGROUND/AIM

Pitted cell count has been described as a sensitive marker of splenic function. Recently, pitted cell count was shown to be increased in patients with alcoholic liver disease, and also to be associated with an increased susceptibility to infection. Therefore, our aim in the present study was to assess splenic function in a group of patients with cirrhosis and to determine its possible role in the development of infections.

METHODS

Splenic function was assessed during hospitalization in 44 patients diagnosed as having cirrhosis, and was compared to 18 healthy subjects. Function was evaluated by counting the number of pitted cells in peripheral blood films. Results were the mean value of two independent counts and were expressed as number of pitted cells/100 erythrocytes.

RESULTS

The mean percentage of pitted cells in peripheral blood of cirrhotic patients was significantly greater than that assessed in controls (3.5 +/- 3.7% vs. 1.6 +/- 0.9%, P < 0.01, Mann-Whitney U test). Eighteen patients with cirrhosis (36%) had counts greater than 3.4% (mean + 2 SD of the control group). There were no significant differences between patients with counts above or below 3.4% in terms of liver tests, platelet and reticulocyte counts, the presence of complications, Child-Pugh score and the prevalence of infections. There was no difference in pitted cell count between alcoholic and non-alcoholic cirrhotic patients (3.8 +/- 3.4% vs. 3.1 +/- 2.8% respectively, P, NS). Moreover, the mortality rate and the occurrence of infections were similar in patients with normal and increased pitted cell counts during 1-year follow-up.

CONCLUSION

The increased number of pitted cells in patients with cirrhosis is not related to heptic function and does not represent a risk factor for infections.

Characterization of two new matrices for matrix-assisted laser desorption/ionization mass spectrometry

Three structurally related compounds, 4-hydroxy-33-methoxyphenylpyruvic acid (HMPPA), indole-3 pyruvic acid (IPA), and indole-3-glyoxylic acid have been evaluated as matrix-assisted laser desorption/ionization (MALDI) matrices. HMPPA and IPA were found to be effective matrices for MALDI-MS analysis of proteins and peptides and have been characterized in this work. HMPPA was found to be a particularly good matrix for the analysis of proteins and peptides because of its tolerance towards impurities and the resulting sensitivity in MALDI-MS experiments. Analysis of model proteins and peptides, including those in biological fluid, are demonstrated.

Use of a nitrocellulose film substrate in matrix-assisted laser desorption/ionization mass spectrometry for DNA mapping and screening

A nitrocellulose film is used as a substrate in matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) studies of DNA. PCR products and DNA fragment digests obtained from biochemical procedures can be analyzed with the use of a nitrocellulose substrate in MALDI MS whereas no signal is observed with the use of a stainless steel substrate. In this method, on-probe purification allows for effective elimination of the interfering effects of salts, buffers, and other contaminants that are usually present in DNA samples, which serve as important limiting factors in the DNA molecular ion yield in the MALDI process. The use of the nitrocellulose film substrate also appears to improve the shot-to-shot and sample-to-sample reproducibility of the ion yield due to the more homogeneous coverage of matrix/analyte over the sample surface. With the use of the nitrocellulose substrate, DNA fragments of up to 622 base pairs in complex mixtures provide mass spectra with minimal sample purification. Although only species corresponding to single-stranded DNA were detected, a mass calibration scheme was established allowing an accuracy of within one base pair for fragments of < 250 bp under the experimental conditions. Despite the low mass resolution of the spectra obtained, the method has been successfully used for rapid DNA screening for sample disease genes and PCR products.

[Correlation study of allelic gene deletion of nm23-H1 and human colorectal carcinoma metastasis]

In recent years, a tumor suppressor gene nm23 has been found to be associated with decreased tumor metastatic potential. Allelic deletion, mutation and low expression of this gene has been correlated with tumor metastatic potential in a number of tumors. There are two known isotypes of human nm23 gene, named nm23-H1 and nm23-H2. We examined DNA from 23 cases of colorectal carcinomas and their corresponding normal mucosa using Southern blot hybridization with nm23-H1 cDNA probe. Five cases with allelic deletion of nm23-H1 gene were found, with allelic deletion rate of 57. 1% (4/7) in cases with metastasis to lymph node, liver or other organs, and 6.2% (1/16) in cases without metastases (P < 0.005). There is no correlation between allelic deletion and tumor size, location or differentiation. This result indicates that nm23-H1 gene plays an important role in the metastasis of colorectal carcinoma.

Experimental renal artery stenosis and angioplasty. The mechanism of the angioplasty

The mechanism of percutaneous transluminal renal angioplasty (PTRA) was studied in 18 dogs. The dogs were divided into two groups. Seven dogs were in the early group and eleven were within 1-3 weeks after PTRA. A 4/0 resorbable chronic catgut was used to ligate subtotally the renal artery to create fibromuscular dysplasia. PTRA was performed after renal artery stenosis for 6-8 weeks. The changes of ultrastructure of renal artery were studied. A contrary orientation balance hypothesis was proposed to explain the mechanism of PTRA.

Body composition and bone mineral density in untreated and treated patients with celiac disease

Body composition and bone mineral density (BMD) were studied by X-ray absorptiometry in 20 untreated and 12 treated women with celiac disease, as well as in 85 age-matched control women. Untreated patients had a significantly lower body weight, fat mass, lean tissue mass and BMD at the lumbar spine and total skeleton compared to controls (p < 0.001 for all parameters). Treated patients had also a significantly lower body weight (p < 0.01) fat mass (p < 0.05) and bone mineral density at lumbar spine and total skeleton (p < 0.05) compared with controls, but lean tissue mass was not diminished. However, treated patients had a significantly higher body weight, fat mass and BMD of the total skeleton compared with untreated celiac patients (p < 0.01 for all parameters). Serum alkaline phosphatase levels were increased in untreated patients but serum 250HD was normal. In conclusion, celiac disease causes a global and almost universal reduction of fat mass and BMD. The results of this cross-sectional study suggest that osteopenia does not seem to be completely restored by adequate treatment. Alteration of vitamin D metabolism was not the cause of osteopenia in the majority of patients.

HPRS-103 (exogenous avian leukosis virus, subgroup J) has an env gene related to those of endogenous elements EAV-0 and E51 and an E element found previously only in sarcoma viruses

The avian leukosis and sarcoma virus (ALSV) group comprises eight subgroups based on envelope properties. HPRS-103, an exogenous retrovirus recently isolated from meat-type chicken lines, is similar to the viruses of these subgroups in group antigen but differs from them in envelope properties and has been assigned to a new subgroup, J. HPRS-103 has a wide host range in birds, and unlike other nontransforming ALSVs which cause late-onset B-cell lymphomas, HPRS-103 causes late-onset myelocytomas. Analysis of the sequence of an infectious clone of the complete proviral genome indicates that HPRS-103 is a multiple recombinant of at least five ALSV sequences and one EAV (endogenous avian retroviral) sequence. The HPRS-103 env is most closely related to the env gene of the defective EAV-E51 but divergent from those of other ALSV subgroups. Probing of restriction digests of line 0 chicken genomic DNA has identified a novel group of endogenous sequences (EAV-HP) homologous to that of the HPRS-103 env gene but different from sequences homologous to EAV and E51. Unlike other replication-competent nontransforming ALSVs, HPRS-103 has an E element in its 3' noncoding region, as found in many transforming ALSVs. A deletion found in the HPRS-103 U3 EFII enhancer factor-binding site is also found in all replication-defective transforming ALSVs (including MC29, which causes rapid-onset myelocytomas).

Faecal alpha 1-antitrypsin concentration in the diagnosis and management of patients with pouchitis

OBJECTIVE

To investigate the role of faecal alpha 1-antitrypsin concentration in the diagnosis and management of patients with ileal pouch-anal anastomosis.

DESIGN

Prospective study.

METHODS

Fifty-two measurements of faecal alpha 1-antitrypsin concentration were taken from 33 patients operated on for ulcerative colitis.

RESULTS

Patients with active pouchitis (44.4 +/- 7.1 mg%) had a three-fold higher mean faecal alpha 1-antitrypsin concentration than patients in remission (13.7 +/- 1.3 mg%; P < 0.0001), than patients who had never had pouchitis (14.4 +/- 2.3 mg%; P < 0.003) and than patients with incontinent ileostomies (12.7 +/- 1.3 mg%; P < 0.004). Faecal alpha 1-antitrypsin measurements were 80% sensitive and 97% specific for active pouchitis. A significant positive correlation between the pouchitis disease activity index and faecal protein loss was observed (r = 0.702; P < 0.0001). The correlations between protein loss and other parameters were weaker (protein loss versus clinical score, r = 0.309; versus endoscopic score, r = 0.583; and versus histologic score, r = 0.558).

CONCLUSION

Faecal alpha 1-antitrypsin concentration is a good indicator of the degree of intestinal inflammation in pouchitis and may be useful as a quantitative index of disease activity in prospective studies.

Sequence of host-range determinants in the env gene of a full-length, infectious proviral clone of exogenous avian leukosis virus HPRS-103 confirms that it represents a new subgroup (designated J)

A genomic DNA library was constructed, in a bacteriophage lambda vector, from line 0 chick embryo fibroblasts (CEFs) infected with HPRS-103, an exogenous avian leukosis virus (ALV; envelope subgroup J) recently isolated from meat-type chickens. The library was screened at high stringency using a full length RAV-1 (subgroup A) proviral probe. From 10(6) plaques, two clones which hybridized strongly to the RAV-1 probe were isolated; one contained a full-length copy of the proviral genome of HPRS-103 and the other contained a copy lacking the 5'-long terminal repeat (LTR) and part of gag. The relative strength of hybridization of RAV-1 and HPRS-103 clones, to RAV-1 probes representing different parts of the proviral genome, indicated that the gag and pol genes of HPRS-103 share a high level of identity with those of RAV-1 but that the env gene and the LTRs are considerably less well conserved. Infectious virus was recovered from CEFs transfected with the full-length clone, as detected by ELISA. The recovered virus appeared to be identical to HPRS-103 by electron microscopy and by Southern blotting of proviral DNA. The recovered virus was shown to be of the same subgroup as HPRS-103 by serum neutralization and receptor interference assays. Sequence analysis of the env gene of HPRS-103 shows that it differs considerably from the env genes of other ALV subgroups, particularly in the host range determinants, consistent with the finding that HPRS-103 represents a new subgroup (designated J).

Rapid screening of genetic polymorphisms using buccal cell DNA with detection by matrix-assisted laser desorption/ionization mass spectrometry

A new approach is developed for the rapid and cost-effective detection of human genetic polymorphisms based on matrix-assisted laser description/ionization mass spectrometric (MALDI MS) detection using a nitrocellulose film substrate. This method employs polymerase chain reaction (PCR) amplification using DNA extracted from buccal cells as templates, followed by direct digestion with restriction enzymes and subsequent analysis by MALDI MS. The extraction of DNA from buccal cells provides a rapid and convenient means for sampling PCR-based diagnostic analysis. The amount of DNA was sufficient as the template for both normal PCR amplifications, and amplifications involving the use of mismatched primers and multiple primers. The MALDI MS methodology has been successfully used for the analysis of such PCR products where restriction fragments generated directly in PCR reactions have been used for detection of carbonic anhydrase and cystic fibrosis transmembrane conductance regulator as model genes. The detection of genetic polymorphisms following routine biological and clinical procedures with the MALDI MS method is demonstrated. The results from MALDI MS analysis are shown to be comparable to those obtained from gel electrophoresis but the MALDI MS method is several orders of magnitude faster than gel electrophoretic techniques. The method described herein should also be readily extended to other areas involving DNA screening and testing.

Matrix-assisted laser desorption/ionization using an active perfluorosulfonated ionomer film substrate

The use of an active Nafion substrate is shown to enhance the performance of MALDI MS. The use of a Nafion substrate with certain matrices can significantly enhance the signals obtained over those observed with a stainless steel probe substrate. Analytes can often be observed with the use of the Nafion substrate that cannot be easily observed with the standard MALDI procedure, and usually a much wider range of peaks can be observed using MALDI from the Nafion substrate than with any single matrix on a stainless steel substrate. This enhancement of signal from the Nafion substrate is observed only with the sequential deposition of the sample and the matrix onto the Nafion film. If the analyte and matrix are premixed, then the effect is not observed. The use of the Nafion substrate has been shown to be particularly effective in analyzing real biological mixtures without prepurification. This has been demonstrated for various samples including the analysis of the products of chemical digests of proteins, protein profiling in milk and egg white samples, cell lysate analysis, and oligonucleotide detection.

A study of optimal configuration and control of a multi-chamber balloon for intraaortic balloon pumping

Balloon configuration and control scheme are important for the optimization of assistance of the failing heart with an intraaortic balloon pumping device. In this work, the configuration of a multi-chamber balloon and control schemes have been investigated by using a hemodynamic model and computer simulation methods. Following the simulation study, physical testing and animal experiments were performed to demonstrate the simulation results. Results show that the optimal configuration and controlled multi-chamber balloon can provide better assistance to the failing heart. Based on the simulation and experimental results, it was found that the shape of the rear chamber of a multi-chamber balloon is critical. The optimal control scheme was to inflate the rear chamber first and deflate it last.

Matrix-assisted laser desorption/ionization mass spectrometry of restriction enzyme-digested plasmid DNA using an active Nafion substrate

Matrix-assisted laser desorption/ionization using a 3-hydroxypicolinic acid matrix from an active Nafion substrate has been used for detection of restriction enzyme-digested double-stranded plasmid DNA using time-of-flight mass spectrometry. DNA strands of up to 267 base pairs were detected with minimal sample purification, although only as species corresponding to single-stranded DNA.

A simulation study of external counterpulsation

To study the haemodynamic effect of external counterpulsation, a computer model has been extended based on our previous work. Using this model, computer simulations have been performed on following aspects: the relationship between blood flow distributions and the control scheme; counterpulsation with and without buttock balloons; effects of duration and time intervals for sequential pulsing; and the potential to use a performance index for the optimal control of this assist device to the failing heart. The results indicate that effective assistance can be achieved by a proper setting of the control scheme. The results also show that this device is effective to improve the circulation status of other organs in addition to the heart. Simulation results agree well with the clinical data.

Ultrastructural observations of the anterior chamber angle tissues in congenital glaucoma

Eighteen trabeculectomy specimens of congenital glaucoma were examined by light and transmission electron microscopy. The results showed that the primary anomalies in congenital glaucoma included the developmental defects of trabecular meshwork, excessive collagen fibrils in the trabecular matrix, shifting forward of ciliary muscle fibres and persistent mesenchymal tissues in the anterior-chamber angle. The authors also pointed out the importance of the secondary lesions of the trabecular meshwork in the pathogenesis of congenital glaucoma.

Chromosome instability in lymphocytes from patients with celiac disease

Cytogenetic studies were performed in celiac disease (CD) patients to determine if the presence of chromosome instability is related to the predisposition to cancer. Chromosome aberrations (CA) and sister chromatid exchange (SCE) frequencies in peripheral blood lymphocyte cultures from untreated CD patients and healthy controls were analyzed. Patients showed aberrations in 23% of cells, while only 3% were detected in the control group (p < 0.0001). The mean frequencies of gaps, breaks and total CA were found to be higher in CD patients compared to controls (p < 0.0001). Breakpoint distribution was nonrandom among chromosomes from celiac patients (p = 0.01), but not among controls (p = 0.04). The frequency of SCE/cell showed a mean value of 6.9 +/- 0.6 in CD patients and 7.3 +/- 0.2 in controls. No statistical differences were found. Breakpoints involved in CD patients presented a strong coincidence with the location of fragile sites (78.6%) and sites of cancer chromosome rearrangements (57.1%), most of them (75%) associated with malignant non-Hodgkin lymphomas. These results suggest that CD is a condition with increased chromosome instability characterized by a high level of CA and normal SCE frequencies, probably related to the increased incidence of cancer.

Cardiovascular responses to external counterpulsation: a computer simulation

A mathematical model of the human cardiovascular system is presented which includes a simulation of cardiac assistance by external counterpulsation. The model was established to study the effects of external counterpulsation on cardiovascular haemodynamics. The closed simulation includes both the left and the right heart and the pulmonary circulation. The model is able to provide data for the behaviour of the system under varying modes of assistance. Our results suggest that control of external counterpulsation is more difficult than control of the intra-aortic balloon pump and requires regulation of a larger number of variables. The results also suggest that a tradeoff exists between improved oxygen delivery to the heart and reduction in the oxygen consumption of the myocardium, an observation similar to that reported for the intra-aortic balloon pump.

Increased rDNA transcriptional activity in celiac disease

The activity of nucleolar organizer regions (NORs) in chromosomes of peripheral blood lymphocyte cultures from 20 healthy subjects and 32 patients with celiac disease (CD) (nine untreated patients, nine treated but with dietary lapses, and 14 treated with gluten-free diet (GFD) and normal small bowel histology) was studied. Furthermore, three female patients diagnosed with small bowel non-Hodgkin's lymphoma (NHL) complicating CD were studied. Silver (Ag)-staining technique was used to visualize positive NORs. In each individual, 20 metaphases were analyzed to determine the number of NORs per cell. The average of Ag-NOR+ per cell, expressed as mean +/- SD, was found to be higher in the CD group (6.62 +/- 0.65) compared with controls (5.70 +/- 0.81) (p less than 0.001). This increase was evident in both groups of chromosomes analyzed (D and G). No differences were found among the three groups, but all of them were found to be statistically different compared to controls (p less than 0.001). The NHL complicating CD patients showed a statistically increased frequency of Ag-NORs (7.20 +/- 0.39) with respect to CD patients (p less than 0.02) and controls (p less than 0.001). These findings show an increase of the transcriptional activity of rDNA in CD that could be related to the high incidence of malignancy in this pathology. Longitudinal studies of CD patients should be performed to confirm this evidence.

Celiac sprue after surgery of the upper gastrointestinal tract. Report of 10 patients with special attention to diagnosis, clinical behavior, and follow-up

The clinical onset of celiac sprue (CS) may be precipitated by upper digestive tract surgery. We report a series of 10 patients who developed CS after diverse types of peptic ulcer surgery. Six were male and 4 female. Gastrectomy with Billroth II anastomosis was performed in 5 patients, truncal vagotomy and pyloroplasty in 2, parietal cell vagotomy and pyloroplasty in 1, and vagotomy with gastrojejunal anastomosis in 2. We found that eight patients had had previous symptoms that suggested CS. Symptoms occurred early in the postoperative period. Severe diarrhea and striking weight loss were the most prominent clinical findings. The response to gluten-free diet was independent of the type of surgical procedure performed and was similar to that observed in the general celiac population.