Protective effect of the angiotensin-converting enzyme inhibitor perindopril on diabetic glomerulopathy in streptozotocin-induced diabetic rats

OBJECTIVES

To evaluate the protective effect of the angiotensin-converting enzyme inhibitor perindopril on diabetic glomerulopathy in rats with experimentally induced diabetes and explore its possible mechanisms.

METHODS

Ninety-two adult male Wistar rats were randomly allocated into diabetes mellitus (DM), diabetes mellitus + perindopril (DMP) and control (C) groups. According to the duration of diabetes or observation (1, 3, 6 months), each group was randomly subdivided into DM1, DM3, DM6; DMP1, DMP3, DMP6; and C1, C3, C6 groups. Diabetes was induced by intraperitoneal injection of streptozotocin. The rats in the DMP groups received perindopril 1 mg.kg-1.d-1, through gastric intubation. Urinary protein excretion rate was determined by the method of Coomassie brilliant blue. Plasma renin activity, renal tissue renin activity, and plasma and renal tissue angiotensin II concentration were assayed by radioimmunoassay (RIA). Renal tissue total RNA was extracted by the Chomezymskis AGPC method. Renal angiotensinogen mRNA expression level was assessed by slot blot hybridization using a full length rat angiotensinogen cDNA probe labelled with 32P-dCTP and a random primer.

RESULTS

There was increased activity of the renin angiotensin system in diabetic rats. Perindopril decreased proteinuria and delayed the progression of glomerular basement membrane thickening. However, it did not reduce the expansion of the mesangial matrix (P < 0.05). Renin activity increased and angiotensin II concentration decreased significantly in both plasma and renal tissue in diabetes + perindopril groups (P < 0.05).

CONCLUSIONS

Perindopril may help prevent the progression of diabetic glomerulopathy, and the inhibition of renin angiotensin system activity may be a mechanism for this action.

Segmental defect of the intestinal musculature associated with ileal atresia and biliary atresia

A full-term baby boy with a segmental defect of the ileal musculature associated with terminal ileal and biliary atresia is presented. The newborn had a dilated loop of the ileum 30 cm proximal to the ileal atretic site. Pathological study results showed absence of the intestinal musculature with relatively intact mucosa. Foci of recent muscular necrosis were found in the lesion. One month later, relaparotomy was performed because of persistent jaundice and hepatic duct atresia was confirmed. Segmental defect of the intestinal musculature associated with ileal atresia and biliary atresia has not been reported in the literature. The authors emphasize that in the management of this unusual defect, one should pay attention to the multiple associated malformations.

Vitamin A deficiency reduces the responsiveness of pineal gland to light in Japanese quail (Coturnix japonica)

Synthesis of melatonin in pineal gland is under the control of light environment. The recent finding of the presence of rhodopsin-like photopigment (pinopsin) and retinal in the avian pinealocytes has led to a hypothesis that vitamin A is involved in photoresponses of the pineal gland. We have thus analyzed the effect of vitamin A deficiency on the regulatory system of melatonin synthesis in the pineal gland of Japanese quail. Depletion of vitamin A from Japanese quails was attained by feeding them with a vitamin A-free diet supplemented with retinoic acid. In the vitamin A-deficient birds, diurnal rhythm in melatonin production persisted such that the phase of the wave was similar to that seen in the control birds. However, the amplitude of the nighttime surge of pineal melatonin was damped by vitamin A deficiency. When the control birds were briefly exposed to light at night, pineal melatonin dropped to the daytime level. In contrast, only slight decrease was observed in the vitamin A-deficient quails. The light responsiveness was restored after feeding the vitamin A-deficient quails with the control diet for 1 week. These results indicate that vitamin A plays essential roles in maintaining sufficient responsiveness of the avian pineal gland to photic input.

[Micellar paper chromatographic separation of structural isomers of diphenylmethyl alcohols and their chromatographic behaviour]

Structural isomers of nine diphenylmethyl alcohols (DPMA) have been separated by paper chromatography with sodium dodecylsulfate(SDS) micellar pure water solution as mobile phase and their Ri data are measured in different concentrations of SDS surfactant aqueous solution with no other additives. However, the curves of Cm vs Ri/(1 - Ri) deviate considerably from the Armstrong's ideal curve and are sawtoothed. The reason is that there is a big stereoscopic effect of DPMA compounds. The partly antibinding behaviour of the sawtoothed shapes comes from the effect which decides that DPMA cannot enter micellar core, otherwise the entropy of micellar system would be reduced or micellar will be broken, although both of them have hydrophobic property. One of the Armstrong's equations is shown as: [formula: see text] In this case, Km in the equation is negative. The above equation comes from a special condition in which there is only one type of micelle, however, there are several kinds of micelles for real system which is in dynamic equilibrium. Armstrong gave the correct pseudophase retention equation for 2:1 complexes [formula: see text] The DPMAs' chromatographic behaviour is the synthetic results of K1 and K2, both of which can be more than or less than zero, respectively or simultaneously, so the curves show sawtoothed shapes. The suitability of the relationship between the solutes' molecular structures and the micellar shapes and sizes is the main driving force of chromatographic separation.

[Effect of HE-NE laser acupuncture on the spleen in rats]

The splenic sinuses, lymphocytes and antigen presenting cells in the spleen of rat stimulated by He-Ne laser acupuncture were observed by using TEM to investigate the ultrastructural changes of them. The width of endothelial interstice was increased, hence a lot of blood cells oozed out of the splenic sinuses. There were numerous activated T cells which contained abundant mitochondria and ribosome in the periarterial lymphatic sheaths. The B cells were gradually differentiated into large lymphocytes, immature and mature plasmatic cells with a lot of endoplasmic reticula. They were prominently increased in the splenic nodules. The macrophages had short processes with numerous folds and microvilli and tended to neighboring lymphocytes. The nucleus pores were increased. There were a lot of vacuoles, phagosome and mitochondria were closed to macrophages and lymphocytes. In conclusion the activities of the cellular immunity and humoral immunity were enhanced by laser.

[Effects of electroacupuncture on the subcutaneous mast cells of zusanli acupoint in rat with unilateral sciatic nerve transection]

Electroacupuncture could induce the convergence and degranulation of subcutaneous mast cells in acupoints. After unilateral transection of sciatic nerve, we studied the numbers of subcutaneous mast cells and its degranulation in bilateral Zusanli and Xiajuxu acupoints with electroacupuncture in Zusanli. We found that sciatic nerve transection could reduce the total numbers of mast cells and the degranulation numbers of mast cells in Zusanli. The results suggested peripheral nerves play an important role in the convergence and degranulation of mast cells in acupoints by electroacupuncture induction.

Diurnal fluctuation in the enzyme activity and the messenger RNA level of pineal serotonin N-acetyltransferase in normal and hereditary microphthalmic rats

The enzyme activity and the messenger RNA level of pineal serotonin N-acetyltransferase were more than 20- and 50-fold higher, respectively, in the dark period than in the light period in normal rats. In hereditary microphthalmic rats, however, the serotonin N-acetyltransferase activity and its mRNA level did not undergo a great diurnal change through the light and dark periods. These results indicate that the diurnal rhythms of the activity and the mRNA level of serotonin N-acetyltransferase are not detected in the pineal gland of hereditary blind rats, suggesting free-running rhythms in individual animals due to desynchronization of their circadian rhythms by a lack of their optic nerve.

[Inhibitory effect of samarium-153-labeled ethylenediaminetetramethylene phosphonate (EDTMP) on bone invasion and osteolysis in Walker 256 carcinoma bearing rats]

OBJECTIVE

To investigate the inhibitory effect of samarium-153 EDTMP on bone invasion and osteolysis in Walker 256 carcinoma bearing rats.

METHODS

Invasion and resorption of tibia by Walker 256 carcinoma in rats were evaluated by X-ray and histological examination.

RESULTS

Intravenous administration of 153Sm-EDTMP at a dose of 74 or 148 MBq/kg, the rat numbers with tibia invasion and bone resorption were reduced by fifty percent. 153Sm-EDTMP at a dose of 37 MBq/kg still exhibited inhibitory effect on bone invasion and osteolysis as compared with the control group. However, there was no indication of change in the weight of primary tumor even at the highest dose utilized.

CONCLUSION

Samarium-153 EDTMP can inhibit bone invasion and osteolysis by Walker 256 carcinoma in rats, but it has no effect on the growth of the transplanted tumor. Therefore, that the effect of 153Sm-EDTMP is due to a reduction in tumor growth leading to decreased bone invasion and osteolysis can be reasonably ruled out.

High lung inflation increases mRNA levels of ECM components and growth factors in lung parenchyma

Remodeling of pulmonary capillaries occurs after chronic increases in capillary pressure (e.g., mitral stenosis). Also, remodeling of pulmonary arteries begins within 4 h of increased wall stress and is endothelium dependent. We have previously shown that high lung inflation increases wall stress in pulmonary capillaries. This study was designed to determine whether high lung inflation induces remodeling of the extracellular matrix (ECM) in lung parenchyma. Open-chest rabbits were ventilated for 4 h with 9-cmH2O positive end-expiratory pressure (PEEP) on one lung and 1-cmH2O PEEP on the other (High-PEEP group), or with 2-cmH2O PEEP on both lungs (Low-PEEP group). An additional untreated control group was also included. We found increased levels of mRNA in both lungs of High-PEEP rabbits (compared with both the Low-PEEP and untreated groups) for alpha1(III) and alpha2(IV) procollagen, fibronectin, basic fibroblast growth factor, and transforming growth factor-beta1. In contrast, alpha2(I) procollagen and vascular endothelial growth factor mRNA levels were not changed. We conclude that high lung inflation for 4 h increases mRNA levels of ECM components and growth factors in lung parenchyma.

Very high pressures are required to cause stress failure of pulmonary capillaries in thoroughbred racehorses

Thoroughbred horses develop extremely high pulmonary vascular pressures during galloping, all horses in training develop exercise-induced pulmonary hemorrhage, and we have shown that this is caused by stress failure of pulmonary capillaries. It is known that the capillary transmural pressure (Ptm) necessary for stress failure is higher in dogs than in rabbits. The present study was designed to determine this value in horses. The lungs from 15 Thoroughbred horses were perfused with autologous blood at Ptm values (midlung) of 25, 50, 75, 100 and 150 mmHg, and then perfusion fixed, and samples (dorsal and ventral, from caudal region) were examined by electron microscopy. Few disruptions of capillary endothelium were observed at Ptm < or = 75 mmHg, and 5.3 +/- 2.2 and 4.3 +/- 0.7 breaks/mm endothelium were found at 100 and 150 mmHg Ptm, respectively. Blood-gas barrier thickness did not change with Ptm. At low Ptm, interstitial thickness was greater than previously found in rabbits but not in dogs. We conclude that the Ptm required to cause stress failure of pulmonary capillaries is between 75 and 100 mmHg and is greater in Thoroughbred horses than in both rabbits and dogs.

[Study of the expression of the epidermal growth factor-receptor in the laryngeal squamous cell carcinoma and the correlation with clinical pathology characteristics]

OBJECTIVE

The expression of the epidermal growth factor-receptor (EGF-R) in the laryngeal squamous cell carcinoma and the correlation with clinical characteristics of the tumor, difference of tissues.

METHOD

Immunohistochemical detection.

RESULTS

The EGF-R expression was evaluated in 36 laryngeal squamous cell carcinoma and 25 normal laryngeal tissues specimens. The EGF-R expression showed only in one specimen of normal laryngeal tissues, whereas twenty-four of thirty-six carcinomas showed positive staining reaction with the anti EGF-R antibodies. The EGF-R expression did not correlate with age, whereas it was higher in poorly differentiated tumors than in moderately and well differentiated tumors (P < 0.05) and it was higher in T3, 4 of TNM classification than in T1, 2 (P < 0.05). Four patients being the recurrence cancers after the operation had an enhanced expression of EGF-R. Six of seven patients with the metastatic cervicallymph-node involvement showed an enhanced expression of EGF-R.

CONCLUSIONS

The uncontrolled cell growth and proliferation of the laryngeal squamous cell carcinomas may be related to the abnormal EGF-R expression. The enhanced expression of EGF-R can be identified as a poorly prognostic parameter.

[CT-guided percutaneous transthoracic fine needle aspiration biopsy of small peripheral pulmonary lesions]

OBJECTIVE

CT-guided percutaneous transthoracic fine needle aspiration biopsy (PTFNAB) was performed in small peripheral pulmonary lesions, which are not easily diagnosed or accessible to fibrobronchoscopes.

METHODS

Twenty-four sputum negative cases of small pulmonary lesions smaller than 2 cm in diameter were studied. After thin-slide scanning and localization with Somatom DR-H computed tomorgraphy, the pulmonary nodules were biopsied with a 20 Gauge needle guided by a ruler especially designed. Biopsy materials were used for cyto- and histopathologic examination. The diagnosis accuracy of biopsy was evaluated by the result of postoperative pathology and/or observation for 2 years.

RESULTS

Sixteen pulmonary lesions were proved to be malignant and 8 benign. The sensitivity rate was 75.0% (12/16), specitivity rate 8/8 and accuracy rate 83.3% (20/24) according to cytopathology and 87.5% (14/16), 8/8, 91.7% (22/24) by histopathology, respectively. Two cases of early-stage peripheral lung cancer were detected and proved by operation.

CONCLUSION

CT-guided PTFNAB is safe and quick for diagnosis with high accuracy for small peripheral pulmonary lesions which are usually negative in sputum examination and bronchoscopy. PTFNAB should be widely used as routine in the diagnosis of lung neoplasms.

Crystal structure of glycine N-methyltransferase from rat liver

Glycine N-methyltransferase (GNMT) from rat liver is a tetrameric enzyme with 292 amino acid residues in each identical subunit and catalyzes the S-adenosylmethionine (AdoMet) dependent methylation of glycine to form sarcosine. The crystal structure of GNMT complexed with AdoMet and acetate, a competitive inhibitor of glycine, has been determined at 2.2 A resolution. The subunit of GNMT forms a spherical shape with an extended N-terminal region which corks the entrance of active site of the adjacent subunit. The active site is located in the near center of the spherical subunit. As a result, the AdoMet and acetate in the active site are completely surrounded by amino acid residues. Careful examination of the structure reveals several characteristics of GNMT. (1) Although the structure of the AdoMet binding domain of the GNMT is very similar to those of other methyltransferases recently determined by X-ray diffraction method, an additional domain found only in GNMT encloses the active site to form a molecular basket, and consequently the structure of GNMT looks quite different from those of other methyltransferases. (2) This unique molecular structure can explain why GNMT can capture folate and polycyclic aromatic hydrocarbons. (3) The unique N-terminal conformation and the subunit structure can explain why GNMT exhibits positive cooperativity in binding AdoMet. From the structural features of GNMT, we propose that the enzyme might be able to capture yet unidentified molecules in the cytosol and thus participates in various biological processes including detoxification of polycyclic aromatic hydrocarbons. In the active site, acetate binds near the S-CH3 moiety of AdoMet. Simple modeling indicates that the amino group of the substrate glycine can be placed close to the methyl group of AdoMet within 3.0 A and form a hydrogen bond with the carboxyl group of Glu15 of the adjacent subunit. On the basis of the ternary complex structure, the mechanism of the methyl transfer in GNMT has been proposed.

[A retrotransposon-like element Tca1 was used for taxonomic determination of Candida albicans]

We had isolated from Candida albicans a moderately repetitive sequence designated alpha and a retrovirus-like transposable element Tcal (Transposon Candida albicans). The Tcal consisted of two 388bp direct repeats of the alpha element, called LTR (Long Termination Repeat), which was separated by approximately 5.5kb of DNA. A large number of strains from America and China have been grouped based on patterns of hybridization bands visualized on Southern blots of EcoRI digested genomic DNA probed with alpha and Tcal element internal sequence. Strains from same area have higher relatedness than those from different area. The hybridization patterns with URA3 and other DNA probes were also conserved within the groups. alpha element are species specific, no hybridization was observed with genomic DNA of other yeast species. The data presented here indicate that the alpha element can be employed to distinguish between species and to assess strain relatedness within C. albicans, we suggest that Tcal may be relevant to the genomic evolutions of C. albicans and the pathogenic potential of the organism.

Age-of-onset related HLA-DQA1 genetic heterogeneity of insulin-dependent diabetes mellitus

OBJECTIVE

To clarify whether there is an association of insulin-dependent diabetes mellitus (IDDM) susceptibility with HLA-DQA1 locus in adult-onset IDDM.

PATIENTS AND METHODS

Possible heterogeneity in immunogenetic aspects was investigated by comparing the findings on relationship between HLA-DQA1 52 Arg(+) and IDDM predisposition in three groups with different ages of IDDM onset (group A 14 years, group B 15-30 years, group C > 31 years).

RESULTS

The frequency of HLA-DQA1 52 Arg(+) in group A (87.5%) was higher than that in control (53.9%, P < 0.05) and in group B and C (P < 0.05). The frequency of HLA-DQA1 52 Arg(+)/Arg(+) phenotype in group A (75%) was higher than that in group C (23.1%, P < 0.05).

CONCLUSION

The contribution of HLA-DQA1 52 arginine to IDDM susceptibility is heterogeneous. Further study is necessary to clarify the immunogenetic entity of IDDM.

[Effects of curcumin derivatives on the GJIC of normal and tumor cells]

Experiments were conducted by using scrape-loading and dye transfer (SLDT) method to study the gap junction intercellular communication (GJIC) of Chinese hamster lung cells (V79), mouse fibrous cells (Balb/c-3T3), rat liver cells (WB) and human embryonal lung cells (2BS). We also observed the inhibition of the GJIC by TPA and the antagonistic effect of Curcumin derivatives on TPA. The results indicated that V79, WB, 3T3 and 2BS normal cells showed medium level of GJIC, and TPA could inhibit the GJIC to some extents. Curcumin derivatives (91022, 91022-S) could counteract the inhibition of TPA-induced GJIC. It was also found that human lung adenocarcinoma cell (A549) and GLC lacked GJIC, and 91022 could improve the GJIC of A549 cell. It may be related to its anticancer activity.

[A study of CD23 expression and regulation in the patients with asthma]

To study the pathogenesis of asthma, we examined the CD23 expression on peripheral blood mononuclear cells (PBMC) from 25 healthy donors and 28 asthmatic patients with APAAP test. The results demonstrated that CD23 antigen expressed strongly on PBMC from patients and their PBMC correlated positively with their IgE level (r = 0.78 P < 0.01). We investigated the regulation of CD23 expression by IL-4 and IFN-gamma in vitro, the results demonstrated that IFN-gamma could inhibit spontaneous and IL-4 induced expression of CD23. It was suggested that the analysis of the percentage of positive CD23 expression is useful for making diagnosis and assessing severity of asthma and is of significance in elucidating the pathogenesis of the asthma.

Flexible loop in the structure of S-adenosylmethionine synthetase crystallized in the tetragonal modification

S-Adenosylmethionine synthetase (MAT, ATP:L-methionine S-adenosyltransferase, E.C.2.5.1.6.) plays a central metabolic role in all organisms. MAT catalyzes the two-step reaction which synthesizes S-adenosylmethionine (AdoMet), pyrophosphate (PPi) and orthophosphate (Pi) from ATP and L-methionine. AdoMet is the primary methyl group donor in biological systems. MAT from Escherichia coli was crystallized in the tetragonal modification with space group P4(3)2(1)2 using the same conditions as previously yielded crystals of the hexagonal system [Takusagawa, et al., (1996), J. Biol. Chem. 171, 136-147], except for the crystallization temperature. The structure has been determined by molecular replacement at 3.2 A resolution. The overall structure of the tetrameric MAT in the tetragonal modification is essentially the same as the structure found in the hexagonal modification. However there are two remarkable differences between the structures of two modifications. One is the contents in the active sites (holoform vs. apo-form), and the other is the conformation of the flexible loop over the active site (open vs. closed). These differences in the crystal structures are caused solely by the difference in crystallization temperatures (26 degrees C vs. 4 degrees C). We have interpreted the structural data obtained from the X-ray analyses in conjunction with the results of the mechanistic and sequencing studies in terms of possible dynamic motion of the flexible loop. When a substrate/product binds in the active site (hexagonal modification), the loop becomes disordered, apparently due to flexibility at the entrance of the active site as if it acts as a "mobile loop" during the catalytic reaction. On the other hand, when the temperature is decreased, the dynamic motion of the flexible loop may be reduced, and the loop residues enter the active site and close its entrance (tetragonal modification). Thus, the active site of the tetragonal modification is empty despite the crystals being grown in mother liquor containing a large concentration of phosphate (100 mM). There is no significant displacement of amino acid residues in the active site between the holo and apo forms, suggesting that the flexible loop plays an important role in determination of the contents in the active site. Since the functionally important amino acid residues in the active site are all conserved throughout various species, the structures of the active sites and the mechanism of the catalysis are probably essentially identical in the enzymes from a wide range of organisms. However, the substrate KM and Vmax values of MATs from various species are distributed over a wide range. The amino acid residues in the flexible loop regions are poorly conserved throughout various species. Therefore, the wide differences in catalysis rates of MATs from various speeches may be due to the differences in the composition of the flexible loop.

Effect of reducing alveolar surface tension on stress failure in pulmonary capillaries

We previously showed that when pulmonary capillaries are exposed to high transmural pressures, stress failure of the blood-gas barrier occurs. It has been suggested that the surface tension of the alveolar lining layer may protect against stress failure because at high transmural pressures the capillaries bulge into the alveolar spaces. To test this hypothesis, we abolished the gas-liquid surface tension of the alveoli by filling rabbit lungs with normal saline. The lungs were then perfused at capillary transmural pressures of 32.5 or 52.5 cmH2O for 1 min with autologous blood, the blood was washed out with a saline-dextran mixture (3 min), and the lungs were fixed for electron microscopy with buffered glutaraldehyde; all perfusions were done at the same pressure. The frequency of breaks was measured in the capillary endothelial layer, alveolar epithelial layer, and basement membranes, and the data were compared with those in air-filled lungs at the same capillary transmural pressure and lung volume. We found that the frequency of breaks in the endothelium was not significantly different between air and saline filling and that there were fewer breaks in the outer boundary of the epithelial cells. By contrast, after saline filling, a larger number of breaks were seen in the inner boundary of the epithelium. The frequency of disruptions of the inner boundary of the epithelium was closely correlated with the volume of edema fluid collected at the trachea during the perfusion. These breaks in the inner boundary of the epithelium had not previously been seen in air-filled lungs exposed to the same pressures. The results suggest that abolishing the surface tension of the alveolar lining layer removes support from parts of the blood-gas barrier when the capillaries are subjected to a high transmural pressure but that not all portions of the barrier are subjected to the same forces.

Effect of increased duration of high perfusion pressure on stress failure of pulmonary capillaries

We have previously shown that raising the capillary transmural pressure (Ptm) in rabbit lung causes disruption of the capillary endothelium, alveolar epithelium, or sometimes all layers of the wall. In those studies the lungs were perfused with autologous blood (1 min), then saline/dextran (3 min), followed by glutaraldehyde fixative (10 min), all at the same pressure. The present study was designed to determine whether increasing the time of exposure of the capillaries to the increased pressure altered the frequency of stress failure. The procedure was identical to that of the previous study except that the duration of the blood perfusion was extended from 1 to 10 and 100 min. We chose a Ptm of 32.5 cm H2O because our previous studies showed that this caused only a few disruptions per millimeter endothelial and epithelial boundary length (0.7 +/- 0.4 and 0.9 +/- 0.6 (SE), respectively). Ten New Zealand white rabbit lungs were perfused with autologous blood plus homologous blood from additional rabbits for 10 and 100 min. After 100 min of blood perfusion the number of disruptions per millimeter endothelial and epithelial boundary length (0.66 +/- 0.4 and 0.52 +/- 0.33 (SE), respectively) was not significantly different from the earlier study. Thus, increasing the duration of the increased Ptm during blood perfusion by 100-fold did not alter the incidence of stress failure. These results indicated that any viscoelastic behavior resulting in further strain and ultimately failure of the capillary walls is insignificant over a wide range of exposure times to increased pressure under the conditions of this study.

Pulmonary capillaries are more resistant to stress failure in dogs than in rabbits

We previously showed that stress failure of pulmonary capillaries occurs at transmural pressures of approximately 50 cmH2O (40 mmHg) and above in rabbit lung. In this study, we examined whether pulmonary capillaries are more resistant to failure in dogs than in rabbits. This might be expected because of the greater athletic ability of dogs and therefore their presumably greater tolerance to large cardiac outputs and higher pulmonary vascular pressures. The lungs of 12 anesthetized mongrel dogs [22.1 +/- 5.2 (SD) kg] were perfused in situ with autologous blood and then with saline-dextran (5 min) and glutaraldehyde solution (10 min), all three perfusions at the same preset transmural pressure of 32.5, 72.5, 92.5, or 112.5 cmH2O. In dogs, the stress failure curves relating break number per millimeter of epithelium and endothelium were right shifted by approximately 40 cmH2O compared with rabbits. Blood-gas barrier thickness was significantly greater than in rabbits at 32.5 cmH2O, and unlike in rabbits, neither total nor interstitial thickness increased significantly with increasing pressure. These results indicate that pulmonary capillaries are more resistant to stress failure in dogs than rabbits.

[Lymphatic metastasis in central direction and bowel axial direction in colonic cancers]

485 lymph nodes were founded by palpation in 44 R3 resected specimens of colonic cancers. In the bowel axial direction, the rate of lymphatic metastasis was 6.8%, which accound for 9.6% of the positive lymph node metastasis. All these positive nodes were limited from 10 cm proximal to 5 cm distal to the tumor. In the central direction, the rate of mesenteric lymphatic metastasis was 20.4%, and the rate of lymphatic metastasis at the root of mesentery was 4.5%, which accounted for 38.1% of the positive lymph node metastasis. Compared to the bowel axial direction, mesenteric lymphatic metastasis in the central direction was more common and should be carefully disseted during radical operation.

Pulmonary microvascular permeability. Responses to high vascular pressure after induction of pacing-induced heart failure in dogs

The pressure threshold for injury of pulmonary capillaries is approximately 50 to 55 cm H2O in the canine lung, as measured by changes in the filtration coefficient (Kf,c). Since the pulmonary endothelial basement membrane has been observed to thicken in patients with heart failure and pulmonary venous hypertension, we hypothesized that both baseline permeability and the threshold for high-vascular-pressure injury would be altered as a result. Dogs (n = 12) were chronically paced at 245 beats per minute for approximately 4 weeks, then were paced at 225 beats per minute for an additional 3 weeks. Lung lobes from anesthetized paced dogs and additional control dogs (n = 14) were then isolated, ventilated, and perfused with blood. Although vascular resistance was increased nearly threefold and vascular compliance reduced by 50% in the paced group, Kf,c referenced to 1 g blood-free dry weight was no different from control. Despite this lack of difference at normal pulmonary vascular pressures, several significant results were obtained. First, in the paced group there was a significant increase in the threshold for high-vascular-pressure injury: Kf,c measured at pulmonary vascular pressures commonly seen in heart failure (20 to 50 cm H2O) were significantly less in this group compared with control. Model predictions showed that in vivo, this difference in Kf,c would result in a 50% reduction in the amount of water and protein cleared across the pulmonary capillary endothelial barrier in the paced group.(ABSTRACT TRUNCATED AT 250 WORDS)

Pathogenesis of high-altitude pulmonary oedema: direct evidence of stress failure of pulmonary capillaries

The pathogenesis of high-altitude pulmonary oedema (HAPE) is disputed. Recent reports show a strong correlation between the occurrence of HAPE and pulmonary artery pressure, and it is known that the oedema is of the high-permeability type. We have, therefore, proposed that HAPE is caused by ultrastructural damage to pulmonary capillaries as a result of stress failure of their walls. However, no satisfactory electron microscopy studies are available in patients with HAPE, and animal models are difficult to find. Madison strain Sprague-Dawley rats show a brisk pulmonary pressure response to acute hypoxia and are susceptible to HAPE. We exposed 13 Madison rats to a pressure of 294 torr for up to 12.5 h, or 4 rats to 236 torr for up to 8 h. Pulmonary arterial or right ventricular systolic pressures measured with a catheter increased from 30.5 +/- 0.5 (SEM) in controls (n = 4) to 48 +/- 2 torr (n = 11). The lungs were fixed for electron microscopy with intravascular glutaraldehyde. Frothy bloodstained fluid was seen in the trachea of three animals. Ultrastructural examination showed evidence of stress failure of pulmonary capillaries, including disruption of the capillary endothelial layer, or all layers of the wall, swelling of the alveolar epithelial layer, red blood cells (RBCs) and oedematous fluid in the alveolar wall interstitium, proteinaceous fluid and RBCs in the alveolar spaces, and fluid-filled protrusions of the endothelium into the capillary lumen.(ABSTRACT TRUNCATED AT 250 WORDS)

Pathogenesis of high-altitude pulmonary oedema: direct evidence of stress failure of pulmonary capillaries

The pathogenesis of high-altitude pulmonary oedema (HAPE) is disputed. Recent reports show a strong correlation between the occurrence of HAPE and pulmonary artery pressure, and it is known that the oedema is of the high-permeability type. We have, therefore, proposed that HAPE is caused by ultrastructural damage to pulmonary capillaries as a result of stress failure of their walls. However, no satisfactory electron microscopy studies are available in patients with HAPE, and animal models are difficult to find. Madison strain Sprague-Dawley rats show a brisk pulmonary pressure response to acute hypoxia and are susceptible to HAPE. We exposed 13 Madison rats to a pressure of 294 torr for up to 12.5 h, or 4 rats to 236 torr for up to 8 h. Pulmonary arterial or right ventricular systolic pressures measured with a catheter increased from 30.5 +/- 0.5 (SEM) in controls (n = 4) to 48 +/- 2 torr (n = 11). The lungs were fixed for electron microscopy with intravascular glutaraldehyde. Frothy bloodstained fluid was seen in the trachea of three animals. Ultrastructural examination showed evidence of stress failure of pulmonary capillaries, including disruption of the capillary endothelial layer, or all layers of the wall, swelling of the alveolar epithelial layer, red blood cells (RBCs) and oedematous fluid in the alveolar wall interstitium, proteinaceous fluid and RBCs in the alveolar spaces, and fluid-filled protrusions of the endothelium into the capillary lumen.(ABSTRACT TRUNCATED AT 250 WORDS)

Crystallization and preliminary X-ray diffraction studies of glycine methyltransferase from rat liver

Glycine methyltransferase from rat liver is a tetrameric enzyme with 292 amino acid residues in each identical subunit and catalyzes the AdoMet-dependent methylation of glycine to form sarcosine. The enzyme was crystallized by the hanging drop vapor diffusion method, using polyethylene glycol 4000 as a precipitant. The crystal belongs to the orthorhombic space group P2(1)2(1)2, with unit cell dimensions of a = 86.4, b = 175.7, c = 45.5 A and with two subunits in the asymmetric unit. The crystals diffract beyond 2.4 A resolution, and a set of 2.4 A resolution data were measured.

Comparative aspects of the strength of pulmonary capillaries in rabbit, dog, and horse

In previous studies of rabbit and dog lung, we demonstrated stress failure of pulmonary capillaries at high transmural pressures (Ptm). The Ptm necessary to elicit stress failure was 40 cmH2O higher in dog than rabbit, and the total blood-gas barrier (BGB) thickness was greater in dog than rabbit. This suggests that stress failure may be related to BGB thickness, and is consistent with the Laplace relationship which states that wall stress is proportional to capillary radius but inversely proportional to wall thickness. In the present studies, we compared BGB thickness and an index of capillary radius in lungs from 3 rabbits, 3 dogs, and 2 horses perfusion fixed at a Ptm of approximately 30 cmH2O. Thicknesses of the BGB were measured at right angles to the barrier at random points on the capillary wall determined by test line intersections. Capillary radius was determined from the mean of major and minor axes measured on electron micrographs. Capillary pressure for failure in the horse was taken to be the mean of pulmonary arterial and left atrial pressures observed in galloping thoroughbreds known to develop exercise-induced pulmonary hemorrhage, although the actual pressure required for failure may be less than this. Average capillary radii were 3.6, 3.4, and 3.2 microns for rabbits, dogs, and horses, respectively. We found that the BGB was thinnest in the rabbit, intermediate in the dog, and thickest in the horse. Calculated capillary wall stress values for the median total BGB thickness at a nominal Ptm of 30 cmH2O were 2.5 x 10(4), 1.7 x 10(4), and 1.5 x 10(4) N.m-2 for rabbits, dogs, and horses, respectively. This species ranking fits with the pressures required to cause stress failure which are approximately 50, 90, and 130 cmH2O in rabbit, dog, and horse, respectively. We conclude that the differences in capillary radius of curvature and BGB thickness account for some of the observed differences in Ptm necessary to cause stress failure. However, other factors may also be important in determining the strength of the BGB.

Structure of trichosanthin at 1.88 A resolution

Trichosanthin (TCS) is one of the single chain ribosome-inactivating proteins (RIPs). The crystals of the orthorhombic form of trichosanthin have been obtained from a citrate buffer (pH 5.4) with KCl as the precipitant. The crystal belongs to the space group P2(1)2(1)2(1) with a = 38.31, b = 76.22, c = 79.21 A. The structure was solved by molecular replacement method and refined using the programs XPLOR and PROLSQ to an R-factor of 0.191 for the reflections within the 6-1.88 A resolution range. The bond length and bond angle in the protein molecule have root-mean-square deviations from ideal value of 0.013 A and 3.3 degrees, respectively. The refined model includes 247 residues and 197 water molecules. The TCS molecule consists of two structural domains. The large domain contains six alpha-helices, a six-stranded sheet, and an antiparallel beta-sheet. The small domain has a largest alpha-helix, which shows a distinct bend. The possible active site of the molecule located on the cleft between two domains was proposed. In the active site Arg-163 and Glu-160, Glu-189 and Arg-122 form two ion pairs, Glu-189 and Gln-156 are hydrogen bonded to each other. Three water molecules are bonded to the residues in the active site region. The structures of TCS molecule and ricin A-chain (RTA) superimpose quite well, showing that the structures of the two protein molecules are homologous. Comparison of the structures of the TCS molecule in this orthorhombic crystal with that in the monoclinic crystal indicates that there are no essential differences of the structures between the two protein crystals.

Refined crystal structure of mitochondrial malate dehydrogenase from porcine heart and the consensus structure for dicarboxylic acid oxidoreductases

The crystal structure of mitochondrial malate dehydrogenase from porcine heart contains four identical subunits in the asymmetric unit of a monoclinic cell. Although the molecule functions as a dimer in solution, it exists as a tetramer with 222 point symmetry in the crystal. The crystallographic refinement was facilitated in the early stages by using weak symmetry restraints and molecular dynamics. The R-factor including X-ray data to 1.83-A resolution was 21.1%. The final root mean square deviation from canonical values is 0.015 A for bond lengths and 3.2 degrees for bond angles. The resulting model of the tetramer includes independent coordinates for each of the four subunits allowing an internal check on the accuracy of the model. The crystalline mitochondrial malate dehydrogenase tetramer has been analyzed to determine the surface areas lost at different subunit-subunit interfaces. The results show that the interface with the largest surface area is the same one found in cytosolic malate dehydrogenase. Each of the subunits contains a bound citrate molecule in the active site permitting the elaboration of a model for substrate binding which agrees with that found for the crystalline enzyme from Escherichia coli. The environment of the N-terminal region of the crystallographic model has been studied because the functional protein is produced from a precursor. This precursor form has an additional 24 residues which are involved in mitochondrial targeting and, possibly, translocation. The crystallographic model of mitochondrial malate dehydrogenase has been compared with its cytosolic counterpart from porcine heart and two prokaryotic enzymes. Small but significant differences have been found in the polar versus nonpolar accessible surface areas between the mitochondrial and cytosolic enzymes. Using least squares methods, four different malate dehydrogenases have been superimposed and their consensus structure has been determined. An amino acid sequence alignment based on the crystallographic structures describes all the conserved positions. The consensus active site of these dicarboxylic acid dehydrogenases is derived from the least squares comparison.

Clinical studies on the mechanism for acupuncture stimulation of ovulation

Ovulatory dysfunction is commonly seen in gynecology clinic. It may cause infertility, amenia, functional uterine bleeding and a variety of complications. This research according to TCM theory records treating with acupuncture 34 patients suffering from ovulatory dysfunction. Changes in clinical symptoms and some relative targets are reported, plus findings in animal experiments. The effect of acupuncture in improving ovulation and the rationale are discussed. According to TCM theory concerning the generative and physiologic axis of women, this research involved the following points: Ganshu (UB 18), Shenshu (UB 23), Guanyuan (Ren 4), Zhongji (Ren 3), and Sanyinjiao (Sp 6). The reinforcement and reduction of acupuncture enables it to strengthen liver and kidney. Through the Chong and Ren channels it nourishes uterus to adjust the patient's axis function and recover ovulation. Treated on an average of 30 times, the patients' symptoms improved to varying degrees. The marked effective rate was 35.29%, the total effective rate being 82.35%. BBT, VS, CMS, and B ultrasonic picture all improved to some degree. The results also showed that acupuncture may adjust FSH, LH, and E2 in two directions and raise the progesterone level, bringing them to normal. The animal experiments confirmed this result. Results showed that acupuncture may adjust endocrine function of the generative and physiologic axis of women, thus stimulating ovulation. The results of this research will provide some scientific basis for treating and further studying this disorder.

Clinical evaluation of radioimmunoimaging with 131I-C0C183B2 monoclonal antibody against ovarian carcinoma by intraperitoneal injection

Forty-eight cases subjected to radioimmunoimaging (RII) by intraperitoneal injection with 131I-C0C183B2 monoclonal antibody (MAb) prepared in our laboratory were studied. Thirteen of 14 cases of proved primary ovarian carcinoma were positive. In 11 follow-up cases of ovarian carcinoma after initial surgery and chemotherapy, 5 recurrences were positive and 6 cases without recurrence were negative; all were confirmed histopathologically after a second operation. One false negative was ovarian mucinous adenocarcinoma, which also negatively stained with C0C183B2 by the peroxidase anti-peroxidase method. Twenty of 23 cases of nonepithelial or metastatic carcinoma of the ovary, benign tumors, and benign diseases were negative. The sensitivity and specificity were 94.7 and 89.7%, respectively. If patients had complications with ascites, the MAb which positively stained with the cancer cells in the ascites was chosen for RII. For follow-up cases PAP staining with the tumor tissue from the initial surgery and the MAb should be done before RII. These are the principal factors that increase the positive rate and accuracy of RII. The intraperitoneal route seems to be a valuable method for clinical staging and tumor localization as well as for follow-up use.

Short-term reversibility of ultrastructural changes in pulmonary capillaries caused by stress failure

We previously showed that when the pulmonary capillaries in anesthetized rabbits are exposed to a transmural pressure (Ptm) of approximately 40 mmHg, stress failure of the walls occurs with disruption of the capillary endothelium, alveolar epithelium, or sometimes all layers. The present study was designed to determine whether some of the ultrastructural changes are rapidly reversible when the capillary pressure is reduced. To test this, the Ptm was raised to 52.5 cmH2O for 1 min of blood perfusion and then reduced to 12.5 cmH2O for 3 min of saline-dextran perfusion, followed by intravascular fixation at the same pressure. In another group of animals, the pressure was elevated for 1 min of blood and 3 min of saline-dextran before being reduced. The results were compared with previous studies in which the capillary pressures were maintained elevated at 52.5 cmH2O during the entire procedure. Control studies were also done at sustained low pressures. The results showed that the number of endothelial and epithelial breaks per millimeter and the total fraction area of the breaks were reduced when the pressure was lowered. For example, the number of endothelial breaks per millimeter decreased from 7.1 +/- 2.1 to 2.4 +/- 0.7, and the number of epithelial breaks per millimeter fell from 11.4 +/- 3.7 to 3.4 +/- 0.7. There was evidence that the breaks that closed were those that were initially small and were associated with an intact basement membrane. The results suggest that cells can move along their underlying matrix by rapid disengagement and reattachment of cell adhesion molecules, causing breaks to open or close within minutes.(ABSTRACT TRUNCATED AT 250 WORDS)

High lung volume increases stress failure in pulmonary capillaries

We previously showed that when pulmonary capillaries in anesthetized rabbits are exposed to a transmural pressure (Ptm) of approximately 40 mmHg, stress failure of the walls occurs with disruption of the capillary endothelium, alveolar epithelium, or sometimes all layers. The present study was designed to test whether stress failure occurred more frequently at high than at low lung volumes for the same Ptm. Lungs of anesthetized rabbits were inflated to a transpulmonary pressure of 20 cmH2O, perfused with autologous blood at 32.5 or 2.5 cmH2O Ptm, and fixed by intravascular perfusion. Samples were examined by both transmission and scanning electron microscopy. The results were compared with those of a previous study in which the lung was inflated to a transpulmonary pressure of 5 cmH2O. There was a large increase in the frequency of stress failure of the capillary walls at the higher lung volume. For example, at 32.5 cmH2O Ptm, the number of endothelial breaks per millimeter cell lining was 7.1 +/- 2.2 at the high lung volume compared with 0.7 +/- 0.4 at the low lung volume. The corresponding values for epithelium were 8.5 +/- 1.6 and 0.9 +/- 0.6. Both differences were significant (P less than 0.05). At 52.5 cmH2O Ptm, the results for endothelium were 20.7 +/- 7.6 (high volume) and 7.1 +/- 2.1 (low volume), and the corresponding results for epithelium were 32.8 +/- 11.9 and 11.4 +/- 3.7. At 32.5 cmH2O Ptm, the thickness of the blood-gas barrier was greater at the higher lung volume, consistent with the development of more interstitial edema. Ballooning of the epithelium caused by accumulation of edema fluid between the epithelial cell and its basement membrane was seen at 32.5 and 52.5 cmH2O Ptm. At high lung volume, the breaks tended to be narrower and fewer were oriented perpendicular to the axis of the pulmonary capillaries than at low lung volumes. Transmission and scanning electron microscopy measurements agreed well. Our findings provide a physiological mechanism for other studies showing increased capillary permeability at high states of lung inflation.

Effect of pacing on epinephrine-stimulated atrial natriuretic factor release

Previous in vitro studies showed that epinephrine stimulation can induce atrial natriuretic factor (ANF) release only form the right atrium but not from the left. In addition, sinus node has been shown to play an important role in the release of ANF. In vitro studies were done in isolated left and right rat atria to determine if pacing can induce the left atria to release ANF during epinephrine stimulation. ANF concentrations in the perfusate were measured by a radioimmunoassay method. Epinephrine increased ANF release in the right atria (from 6.3 +/- 0.8 to 10.8 +/- 0.9 pg/min/mg), but not in the unpaced left atria (4.2 +/- 0.4 and 4.2 +/- 0.3 pg/min/mg). However, when the atria were paced, ANF release rose in both the left (from 6.2 +/- 0.5 to 11.5 +/- 1.4 pg/min/mg) and right (from 8.4 +/- 1.15 to 16.6 +/- 1.8 pg/min/mg) atria with epinephrine addition. These results suggest that atrial contraction and tension play an important role in epinephrine-stimulated ANF release.

Mortality and incidence of bladder cancer in benzidine-exposed workers in China

We examined bladder cancer mortality and incidence to 1981 in 1,972 workers employed in benzidine-exposed jobs in Tianjin, Shanghai, and Jilin, China, between 1972 and 1977, and in 1,974 unexposed workers employed during the same time period. In comparison to general population rates, in the benzidine-exposed group the ratio of observed to expected deaths (SMR) was 17.5 (95% C.I.: 7.5-34.5) and the ratio of observed to expected incident cases (SIR) was 25.0 (95% C.I.: 16.9-35.7). No excess was noted in the unexposed group. The 25-fold increase in bladder cancer incidence in the exposed group was related to level of exposure, with the SIR rising from 4.8 for low exposure to 36.2 for medium exposure, and 158.4 for high exposure. Risks were elevated both for producers of benzidine (SIR = 45.7; 95% C.I.: 20.9-86.8) and for users (SIR = 20.9; 95% C.I.: 12.9-32.0) of benzidine dyes. Benzidine-exposed workers who smoked tobacco had a 31-fold risk (95% C.I.: 20.4-46.4), while non-smoking workers had an 11-fold risk (95% C.I.: 3.6-25.8), suggestive of a multiplicative relationship between these two carcinogens.