Application of transcranial Doppler in subarachnoid hemorrhage

Transcranial Doppler (TCD) was dynamically performed on 25 patients with subarachnoid hemorrhage (SAH) before and after treatment. In the first 4 days of clinical course, 3 cases demonstrated elevated intracranial pressure (ICP), 6 cases showed stenosis of blood vessels, and 16 cases gave normal findings. At 7-14 days of clinical course, 20 cases showed vascular spasm or narrowing, 4 cases imparted normal findings and 1 patient died of elevated ICP. After the third TCD performed on the 20th day of the clinical course, 5 cases showed mean blood flow velocities (Vm) below normal values, indicating poor cerebral perfusion, 9 cases still had Vm above normal levels, 10 cases yielded completely normal findings. In conclusion, TCD conducted at different phases of SAH can not only demonstrate the functional and pathological status of cerebral blood vessels following SAH, but also reflect the outcome of clinical features. It is very helpful in the evaluation of the causes and the prognosis of SAH.

Structures and stereochemistry of pseudolarolides K and L, novel triterpene dilactones from pseudolarix kaempferi

Pseudolarolides K(1) and L(2), two novel triterpenedilactones, were isolated from the seeds of Pseudolarix kaempferi, and their structures characterized from spectral data.

Genetic tracing of arterial graft flow surface endothelialization in allogeneic marrow transplanted dogs

In order to trace genetically the source of fallout endothelialization on arterial grafts, six beagle dogs with successful autologous bone marrow transplantation received composite tandem aortic grafts with an isolated, totally impervious Dacron graft and a porous Dacron graft for 12 weeks. For impervious segments, five of 12 fresh tissue samples were Factor VIII/von Willebrand factor + (FVIII/vWF) and seven had faint or negative signals; three of the FVIII/vWF + samples had alpha-actin + smooth muscle cells. Polymerase chain reaction (PCR) study showed eight had a pure donor DNA genotype and four had donor/host mixed, with the donor predominant. Of 12 AgNO3-stained samples, 11 showed pure donor type and one had donor/host mixed, with the donor predominant. For porous segments, all 12 fresh samples had positive flow surface FVIII/vWF and alpha-actin cells. PCR showed all these samples and all 12 AgNO3-stained samples had donor/host mixed type, but the host pattern was predominant. Porous graft healing appears to involve both cellular fallout and tissue ingrowth, and bone-marrow-derived cells may be a source for fallout.

The opioid peptide analog D-Ala2-Met-enkephalinamide decreases bile flow by a central mechanism

The existence of an opioid central pathway that may regulate bile secretion was explored by studying the effect of the intracisternal (i.c.) administration of the opiate D-Ala2-Met-enkephalinamide (DAME) on bile secretion in anesthetized male rats. The i.c. administration of DAME was associated with a dose-related decrease in bile flow that ranged from 12% to 41%, which was prevented by the opiate antagonist naloxone. Bicarbonate secretion into bile decreased significantly after i.c. DAME. Chemical adrenergic denervation and cholinergic pharmacological blockade with atropine did not prevent the DAME-induced decrease in bile flow. The data support the existence of an opioid-mediated pathway that starts in the brain and that contributes to the regulation of bile secretion.

[Investigation on resources and commodities of Chinese medicinal herbs of Jili]

OBJECTIVE

To make clear the current situation of application of the Chinese medicinal herbs of Jili.

METHOD

The medicinal resources and commodities of the berbs in some provinces and cities in China were investigated.

RESULT

The species Tribulus terrestris included in <Pharmacopolia of the Peoples Republic of China> is widely distributed in China. The fruit of T. terrestris which is widely used in China as a traditional medicine is commonly called Yingjili. Being only the fruit of Atriplex entralasiatica Ruanjili is produced mainly in Shandong Province and customarily used as Fructus Tribuli in some areas of Shandong and Hebei Provinces.

CONCLUSION

The current situation of medicinal application of Jili basically conforms to the requirements of <Pharmacopolia of the Peoples Republic of China>. The main variety is Yingjili.

The effects of serum from patients with acute liver failure on the growth and metabolism of Hep G2 cells

In many bioartificial liver systems currently being designed and evaluated for use in fulminant hepatic failure, direct contact is required between the patient's blood and the liver cells in the device. The efficacy of such devices will be influenced by the interaction of fulminant hepatic failure (FHF) patient serum with the cells. We have found that FHF serum inhibits the growth rate and the synthesis of DNA, RNA, and protein; disturbs glutathione homeostasis; and induces morphological changes in cultured human Hep G2 cells. These interactions should influence the design of bioartificial liver devices based on proliferating cell lines and indicate the requirement to pretreat FHF patient plasma to reduce the toxin load.

[The changes of serum estrogen, progesterone and the function of immune system in intrahepatic cholestasis of pregnancy]

OBJECTIVE

To explore the effects of estrogen, progesterone and the function of immune system on intrahepatic cholestasis of pregnancy (ICP).

METHODS

Fifty women with ICP and fifty normal pregnant women were enrolled in the study. The levels of their serum estradiol (E2) and progesterone (P) were measured and cellular immunity and humoral immunity were determined. Radioimmunoassay was used to detect the levels of E2 and P, and APAAP was used to detect cellular immunity.

RESULTS

(1) The level of estrodiol was significantly increased in ICP group than those of normal control group (25.89 +/- 6.85 micrograms/L, 16.92 +/- 4.98 micrograms/L, P < 0.01). (2) The level of CD8+ was decreased (19.06 +/- 1.93%, 26.43 +/- 2.89%) and the ratio of CD4+/CD8+ was increased significantly in ICP group than those of control group (2.23 +/- 0.38, 1.73 +/- 0.23, P < 0.05). (3) There were negative correlation between E2 and CD8+, and positive correlation between E2 and the ratio of CD4+/CD8+.

CONCLUSION

These results suggest that the high level of E2 of ICP patients may result in functional disorder of immune system by the means of estrogen receptor on CD8+. This may be a factor of ICP development.

[DNA content, expression of proliferating cell nuclear antigen and surgical margins in locally advanced laryngeal cancer]

OBJECTIVE

To probe into the relationship between DNA content, PCNA and prognosis.

METHODS

Surgical margins in 34 patients with locally advanced laryngeal cancers were observed by means of antibody to PCNA and DNA content measurements.

RESULTS

The results demonstrated that at neoplasm margins of 1.0, 0.5, and 0 cm, PCNA indices were 8.62%, 17.76% and 50.32% and DNA indices were 0.98, 1.082 and 1.436 respectively. There is a significant difference between 1.0, 0.5 and 0 cm.

CONCLUSION

Moderate and severe atypical hyperplasia of epithelium (AHE) was different from mild AHE and simple hyperplasia of epithelium in the biologic behavior of fission, proliferation and so on and surgical margins should be kept outside the area of moderate AHE.

[Study of the behavior on meso-Tetra (4-sulfophenyl) Porphyrin (TPPS) in the microemulsion system]

The change of absorption spectrum of meso-Tetra (4-sulfophenyl) Porphyrin (TPPS) in microemulsion system (Triton X-100-nonane-pentanol-water) was studied. The electric dissociation constants (Ka ) and dimerization constants (KD) were calculated. It was shown that Ka of TPPS is added but KD of TPPS is decreased in microemulsion system as compared with that in aqueous solution.

Interaction of ethanol and nitric oxide in the hypothalamic-pituitary-gonadal axis in the male rat

Ethanol (EtOH) exerts deleterious actions on reproductive function at all three levels: the hypothalamus, pituitary, and gonad (HPG). Nitric oxide (NO), a newly identified messenger molecular in a variety of biological systems, has been suggested as playing a role in HPG hormone regulation. NO stimulates luteinizing hormone releasing hormone secretion from the hypothalamus and has variable effects on luteinizing hormone release from the pituitary. NO is inhibitory to testosterone production, and it may also directly inhibit some steroidogenic enzymes. Related studies in the accompanying paper have demonstrated that inhibiting NO synthase (NOS) using various NOS inhibitors can prevent the EtOH-induced suppression of testosterone on the male HPG axis, and this action is mainly, although not entirely, due to a direct gonadal effect. To further investigate the role of NO in the HPG axis, we assessed the HPG NO-NOS system by determining NOS mRNA levels, protein levels, and enzyme activity in the presence and absence of EtOH. At the testicular level, EtOH's action did not appear to be mediated by increasing NO content. However, EtOH was able to potentiate NO's suppressive effect on the testicular synthesis system. One locus where EtOH and NO interacted was at the steroidogenic enzyme level. N(G)-nitro-L-arginine methyl ester, a NOS inhibitor, was found to antagonize the EtOH-induced fall on P-450 17alpha-hydroxylase/C17-20 lyase mRNA levels when administered along with EtOH. EtOH had no apparent effect on the pituitary NO-NOS system and its effects on the hypothalamic NO-NOS system do not explain its ability to reduce luteinizing hormone releasing hormone secretion.

Effect of nitric oxide synthase inhibitors on preventing ethanol-induced suppression of the hypothalamic-pituitary-gonadal axis in the male rat

Ethanol (EtOH) suppression of the hypothalamic-pituitary-gonadal (HPG) axis results in broad reproductive malfunction. In the HPG axis, the suppressive effects of EtOH are manifested by decreased serum testosterone, reduced testicular luteinizing hormone (LH) receptor numbers, lowered serum LH and pituitary beta-LH mRNA levels (in castrated animals), and impaired luteinizing hormone releasing hormone (LHRH) release from the hypothalamus. Increasing evidence has suggested that nitric oxide (NO) plays a role in regulation of the HPG axis. NO was shown to stimulate LHRH secretion from the hypothalamus and to have variable effects on LH release from the pituitary. At the gonadal level, NO is inhibitory to testosterone production. NO may directly inhibit some testicular steroidogenic enzymes. To investigate the effect of EtOH, NO, and their interaction on the male HPG axis, three NO synthase (NOS) inhibitors, N(G)-nitro-L-arginine methyl ester, N(G)-nitro-L-arginine, and 7-nitro indazole were used to study overall HPG function in the presence and absence of EtOH. Animals were given intraperitoneal injections of saline, EtOH, various NOS inhibitors, or EtOH, along with NOS inhibitors 2 hr before sacrifice. Serum testosterone and LH concentrations, pituitary beta-LH mRNA levels, hypothalamic LHRH mRNA levels, and LHRH content were determined. It was found that blocking NOS by these NOS inhibitors prevented EtOH-induced suppression of testosterone and, in some cases, serum LH. However, this was not accompanied by concurrent changes with NOS blockade on LHRH mRNA, hypothalamic pro-LHRH or LHRH content or pituitary LH beta mRNA levels. It appears that the protective effect of NOS blockade was largely, although not completely, due to a direct effect at the gonadal level.

Tribulusamide A and B, new hepatoprotective lignanamides from the fruits of Tribulus terrestris: indications of cytoprotective activity in murine hepatocyte culture

Tribulusamides A (1) and B (2), new lignanamides embracing two cinnamic amide parts joined in a cis configuration, were isolated from the fruits of Tribulus terrestris, together with four known compounds, N-trans-feruloyltyramine (3), terrestriamide (4), N-trans-coumaroyltyramine (5), and beta-sitosterol. The structures were elucidated by 2D-NMR spectroscopy. Addition of compounds 1-5, especially 1 and 2, to primary cultured mouse hepatocytes significantly prevented cell death induced by D-galactosamine (D-GalN)/tumor necrosis factor alpha (TNF-alpha).

Reasons for intracranial hypertension and hemodynamic instability during acute elevations of intra-abdominal pressure: observations in a large animal model

In previous studies we reported that an acute elevation in intra-abdominal pressure (IAP) is responsible for the elevation in intracranial pressure (ICP) and mean blood pressure (MBP). Thus far, the reasons for the increased ICP during an acute elevation in IAP and the combined effects of increased IAP and ICP on hemodynamics have not been reported. Five large animals (swine) were studied. Each animal served as its own control. A subarachnoid screw was placed for ICP monitoring. The jugular vein, femoral vein, and femoral artery were cannulated. ICP, MBP, central venous pressure above (CVPA) and below (CVPB) the diaphragm, and PaC02 were monitored after a pneumoperitoneum with C02 was established at 5, 15, and 30 mm Hg of IAP. Cavography was performed to evaluate the morphology of the inferior vena cava at different increments of IAP. Measurements were obtained in reverse Trendelenburg (group 1), supine (group 2), and Trendelenburg (group 3) positions. Multiple regression analysis was used to examine the effects of IAP and positioning in separate models with different blood pressures as dependent variables. Increased IAP significantly increased CVPA, CVPB, ICP, and MBP. There were no changes in cerebral perfusion pressure. The change in position (from group 1 to group 3) significantly increased CVPA and decreased the CVPB. Cavograms performed on animals in the supine position with increased IAP showed a narrowing of the IVC at the level of the diaphragm. Increases in IAP will increase ICP and MBP without altering the cerebral perfusion pressure. A mechanical effect mediated by compression of the inferior vena cava at the level of the diaphragm with increased central venous pressure and decreased drainage from the lumbar plexus and central nervous system is responsible for this effect.

[Discovery of ten strains of non-O1 Vibrio cholerae pigmentogens]

OBJECTIVE

To study the distribution of non-O1 Vibrio cholerae pigmentogens in water and its biological characteristics and pathogenicity.

METHODS

Samples were collected from local source of drinking water and cultured for pathogenic V. cholerae. Non-O1 V. cholerae was isolated and identified with nutrient agar slant instead of KIA.

RESULTS

Ten strains of V. cholerae producing pigment with negative Gram's stain were detected in the source water in Lu' an Prefecture, Anhui Province during 1994 to 1997, which could all met the definition of non-O1 V. cholerae in morphology, cultural characteristics, biochemistry and serology, with systematic identification. Animal experiments showed that it had strong virulence.

CONCLUSION

These strains of V. cholerae cultured in basic cholate agar, nutrient agar slant and blood agar could produce brown pigment, so it was called non-O1 V. cholerae pigmentogens.

[Study on the supercritical-CO2 fluid extraction of Prunus mandshurica oils]

The paper reported technological study on extracting Prunus mandshurica oils by supercritical-CO2 fluid, mainly researched the influence of pressure, temperature, time and flow rate of CO2 on the oil yield, determined optimum technology of extracting the oils, compared the oils from SFE-CO2 and traditional technology.

[Parental origin of extra chromosome 21 in Down syndrome detected by using short tandem repeat DNA polymorphisms after PCR amplification]

OBJECTIVE

To detect the parental origin of extra chromosome 21 in Down syndrome, using two (GT)n polymorphic markers-D21S215 and D21S120.

METHODS

The alleles of D21S215 and D21S120 were amplified by polymerase chain reaction and identified with denaturing polyacrylamide gel electrophoresis followed with Ag-staining. The parental origin of extra chromosome 21 was determined by comparing genotypes of probands with their parents.

RESULTS

The parental origin of extra chromosome 21 was determined in 17 Down syndrome out of 24, with 12 and 5 inherited from mother and father respectively.

CONCLUSION

The parental origin of extra chromosome 21 in Down syndrome can be determined by analyzing the polymorphisms of D21S215 and D21S120. Etiological study of trisomy 21 should be focused on maternal meiosis.

Evidence for circulating bone marrow-derived endothelial cells

It has been proposed that hematopoietic and endothelial cells are derived from a common cell, the hemangioblast. In this study, we demonstrate that a subset of CD34(+) cells have the capacity to differentiate into endothelial cells in vitro in the presence of basic fibroblast growth factor, insulin-like growth factor-1, and vascular endothelial growth factor. These differentiated endothelial cells are CD34(+), stain for von Willebrand factor (vWF), and incorporate acetylated low-density lipoprotein (LDL). This suggests the possible existence of a bone marrow-derived precursor endothelial cell. To demonstrate this phenomenon in vivo, we used a canine bone marrow transplantation model, in which the marrow cells from the donor and recipient are genetically distinct. Between 6 to 8 months after transplantation, a Dacron graft, made impervious to prevent capillary ingrowth from the surrounding perigraft tissue, was implanted in the descending thoracic aorta. After 12 weeks, the graft was retrieved, and cells with endothelial morphology were identified by silver nitrate staining. Using the di(CA)n and tetranucleotide (GAAA)n repeat polymorphisms to distinguish between the donor and recipient DNA, we observed that only donor alleles were detected in DNA from positively stained cells on the impervious Dacron graft. These results strongly suggest that a subset of CD34+ cells localized in the bone marrow can be mobilized to the peripheral circulation and can colonize endothelial flow surfaces of vascular prostheses.

Effects of hyperventilation and hypoventilation on PaCO2 and intracranial pressure during acute elevations of intraabdominal pressure with CO2 pneumoperitoneum: large animal observations

BACKGROUND

The side effects of acute elevations in intraabdominal pressure (IAP) are related to a multifactorial etiology. Previous studies have reported that acute elevations in IAP produce an immediate increase in intracranial pressure (ICP). This study was designed to analyze the reasons for increased ICP during acute elevations of IAP and to determine the combined effects of IAP and changes in ventilation indices on ICP and hemodynamic indices.

STUDY DESIGN

Five pigs were studied. A subarachnoid screw was placed for ICP monitoring. The jugular vein, femoral vein, and femoral artery were cannulated. Mean arterial pressure (MAP), central venous pressure (CVP), ICP, and arterial pressure of carbon dioxide (PaCO2) were monitored before and after carbon dioxide pneumoperitoneum was established at 0, 10, and 20 mmHg of IAP Effects of hyperventilation and hypoventilation were recorded and compared with baseline ventilation. Cavography was performed to evaluate the morphology of the inferior vena cava (IVC) at different levels of IAP. Multiple regression and Student's t-test were used to examine the effects of IAP and ventilation on dependent variables.

RESULTS

The IVC showed a progressive narrowing at the level of the diaphragm as IAP was increased. There was a simultaneous increase in CVP, MAP, and ICP. The mean changes in ICP with hypoventilation were significantly larger than with hyperventilation.

CONCLUSIONS

Acutely increased IAP displaces the diaphragm cranially, narrowing the IVC and increasing intrathoracic pressure. This increases CVP and increases ICP by venous stasis and increased pressure in the sagittal sinus with decreased resorption of cerebrospinal fluid. Hemodynamic changes are directly related to the rise in ICP. Hypoventilation and hypercarbia significantly increase ICP when compared with hyperventilation and hypocarbia. Hyperventilation does not significantly decrease ICP during acute elevations of IAP.

Dynamic and comparative vascular graft healing studies using multiple sequential biopsies

In order to follow the dynamic healing processes of vascular grafts and to minimize the possible animal-to-animal variables involved in study results, we developed a carotid-femoral bypass model with multiple sequential biopsies. After bilateral implantation of 70 cm x 6 mm gelatin-impregnated carotid-femoral bypass grafts in 5 dogs, we biopsied and replaced three 10-cm-long segments of each bypass at 2, 4, and 6 weeks, with final retrieval at 8 weeks after the initial implant. The first surgery and later biopsy procedures were well tolerated with no mortality or morbidity, except for some seroma formation. We observed a dynamic progression of healing processes related to the time course, including perigraft tissue reaction to the graft material and surgical trauma, gradual absorption of the impregnated gelatin, tissue ingrowth into the graft wall, and changes in and healing of the graft surface. Because of the sizeable tissue sample generated from each biopsy, this model also allowed various study approaches to be performed on the same specimen. This experimental model enables study of the continuous dynamic healing processes of the same graft in the same animal, providing the practical advantage of reduction of the number of animals required.

The effect of flow shear stress on endothelialization of impervious Dacron grafts from circulating cells in the arterial and venous systems of the same dog

The purpose of this report was to study effects of shear force and hemodynamic conditions that influence fallout healing in the arterial and venous systems of the same dog. Knitted Dacron grafts made impervious by a 1.5 mm thick coat of silicone rubber bonded to the external surface were implanted for 4 weeks during the same surgery in the descending thoracic aorta (DTA), abdominal aorta (AA) and inferior vena cava (IVC) of each of five dogs. Flow rates were measured during surgery and shear stresses calculated with the Hagen-Poiseuille formula. Full-wall thickness longitudinal tissue sections were embedded in resin and stained with hematoxylin and eosin for light microscopy, and in paraffin for immunocytochemistry studies with Factor VIII/von Willebrand factor, smooth muscle alpha-actin, collagen IV, laminin, and proliferating cell nuclear antigen. Scanning electron microscopy and transmission electron microscopy studies were also performed. AgNO3 was used to determine percentage of endothelial-like cell coverage on the flow surface. All grafts were patent, without hematoma or seroma. Endothelial-like cell coverage was highest in the IVC grafts and lowest in the DTA. Shear stress and flow velocity were significantly lower in IVC grafts than DTA and AA. Proliferating cell nuclear antigen indicated extensive cellular proliferation in the intima and in the interstices of the inner portion of the graft wall. The degree of fallout healing in knitted Dacron grafts made impervious by an external coat of silicone rubber varies inversely with the sheer force of blood flow in these grafts.

Colcemid and econazole do not show aneugenicity in male mouse germ cells

Colcemid (COM) and econazole (EZ) were tested for induction of mitotic arrest and C-mitotic effects in mouse bone marrow cells and for meiotic delay and induction of hyperploidy in mouse spermatocytes after single injection. Doses of 1 and 3 mg/kg COM were used and bone marrow and spermatocytes were sampled at 2, 6, 10, 14 and 18 h. For EZ a dose of 120 mg/kg and intervals of 6, 10, 14 and 18 h were chosen. At 2 h after COM treatment of bone marrow cells the mitotic index and C-mitotic effect were highest, then both decreased from 6 to 18 h. At 18 h the mitotic indices decreased to or significantly below the control level at doses of 1 and 3 mg/kg respectively, whereas the corresponding frequencies of C-mitotic cells were still significantly higher than in the controls. EZ also induced mitotic arrest and C-mitotic effects in mouse bone marrow cells. In contrast to COM, the effects of EZ were highest at 18 h after treatment. COM and EZ caused disturbances in progression from the first to second meiotic division, however, after COM treatment the ratios of MMII to MMI were significantly below the control. In contrast, after EZ treatment the ratios were significantly higher than in the controls. Such differences may result from the different mechanisms by which COM and EZ act on cell cycle progression. COM and EZ did not induce non-disjunction under the experimental conditions. However, EZ induced structural chromosomal aberrations.

Recent progress in the development of tubulin inhibitors as antimitotic antitumor agents

Tubulin protein is a major target of drug molecules, and consequently, tubulin inhibitors have attracted great attention as antimitotic antitumor agents for chemotherapeutic use. Hundreds of synthetic or semisynthetic tubulin inhibitors have been discovered and developed recently that are related to the natural products colchicine, vinblastine, and taxol. Representatives include allothiocolchicinoids, vinorelbine, and taxotere. This review will describe the recent progress being made in the development of novel antimitotic antitumor tubulin inhibitors. The emphasis has been placed on related research in the author's laboratory, including development of colchicine derivatives and other colchicine binding site drugs, such as flavonoids and quinolone derivatives. Syntheses and modifications of novel compounds, biological activity evaluation, and structural activity relationships will be discussed as well. Further research will undoubtedly lead to the discovery of additional tubulin inhibitors that have potential for use as anticancer drugs.

Polymorphism of DXS102 locus in Chinese population and its application to gene diagnosis in hemophilia B family

OBJECTIVE

To establish the polymorphism of DXS102 locus from Xq26.3-27.1 in Chinese population for the gene diagnosis in Hemophilia B family.

METHODS

DNA was extracted from blood samples obtained from Shanghai unrelated volunteer donors with phenol-chloroform method. A total of 23x chromosomes (154 from females, 80 from males) were studied. A hemophilia B family in which a hemophilia B patient has received gene therapy was analyzed. The polymorphism of DXS102 locus in Chinese population was determined with amplified fragment length polymorphisms assay (Amp-FLP), denaturing polyacrylamide gel electrophoresis, silver stain detection. Short tandem repeats (STRs) linkage analysis was used to conduct gene diagnosis in hemophilia B family.

RESULTS

Eight alleles were found at DXS102 locus, of which two alleles were first reported. The repeated number of AC dinucleotide ranges from 13 to 21. And the values of the observed heterozygosity, calculated heterozygosity and polymorphism information content(PIC) were 0.87, 0.80, 0.80 respectively. It was also found that the difference of the allele frequencies of DXS102 in Chinese and European populations was significant. By using the linkage analysis of the DXS102 locus, a family with a hemophilia B patient receiving gene therapy in 1994 was analyzed and meanwhile a carrier in that family was then detected.

CONCLUSIONS

The polymorphism of DXS102 locus reveals significant difference between Chinese and European populations. DXS102 locus can be used as a promising marker for gene diagnosis in hemophilia B family.

Early flow surface endothelialization before microvessel ingrowth in accelerated graft healing, with BrdU identification of cellular proliferation

The purpose of this report was to determine if flow surface endothelialization could precede microvessel ingrowth from the perigraft area in porous Dacron grafts, by using an accelerated graft healing model with short implant periods. Dacron grafts were implanted in the abdominal aorta of 22 dogs and wrapped in autogenous inferior vena cava (IVC), which provided excellent conditions for extramural angiogenesis, microvessel development, and ingrowth toward the graft. Retrieval times were 7 days (n = 4), 8 days (n = 5), 9 days (n = 4), 10 days (n = 3), 11 days (n = 4) and 12 days (n = 3) postoperatively. Graft surfaces were evaluated for thrombus coverage, cell coverage, and the number of micro-ostia. Components and cellular types in the graft wall and on the surface were studied and characterized with H&E, histochemical, and immunocytochemical staining. BrdU labeling was also used, to identify the areas where cells were actively proliferating. All grafts were patent. Although the degree of IVC/graft attachment varied, isolated islands of endothelial-like cells were found at the midgraft areas at each time period, and immunocytochemically confirmed as endothelial cells. There were two healing patterns: (1) surface endothelialization before microvessel/tissue ingrowth from the perigraft areas, and (2) surface endothelialization with full wall microvessel and tissue presence. Surface endothelialization was observed before perigraft tissue ingrowth, indicating that fallout healing is an independent source of endothelialization for porous grafts.