Suppression of experimental abdominal aortic aneurysms by systemic treatment with a hydroxamate-based matrix metalloproteinase inhibitor (RS 132908)

BACKGROUND

Abdominal aortic aneurysms (AAAs) are associated with chronic inflammation, disruption of medial elastin, and increased local production of elastolytic matrix metalloproteinases (MMPs). The purpose of this study was to investigate how treatment with a hydroxamate-based MMP antagonist (RS 132908) might affect the development of experimental AAAs.

METHODS

Male Wistar rats underwent intraluminal perfusion of the abdominal aorta with 50 units of porcine pancreatic elastase followed by treatment for 14 days with RS 132908 (100 mg/kg/day subcutaneously; n = 8) or with vehicle alone (n = 6). The external aortic diameter (AD) was measured in millimeters before elastase perfusion and at death, with AAA defined as an increase in AD (DeltaAD) of at least 100%. Aortic wall elastin and collagen concentrations were measured with assays for desmosine and hydroxyproline, and fixed aortic tissues were examined by light microscopy.

RESULTS

AAAs developed in all vehicle-treated rats, with a mean AD (+/- SE) that increased from 1.60 +/- 0.03 mm before perfusion to 5.98 +/- 1.02 mm on day 14 (DeltaAD = 276.4 +/- 67.7%). AAAs developed in only five of eight animals (62.5%) after MMP inhibition, with a mean AD that increased from 1.56 +/- 0.05 mm to 3.59 +/- 0.34 mm (DeltaAD = 128.1 +/- 18.7%; P <.05, vs vehicle). The overall inhibition of aortic dilatation attributable to RS 132908 was 53.6 +/- 6.8%. Aortic wall desmosine fell by 85.4% in the vehicle-treated rats (1210.6 +/- 87.8 pmol/sample to 176.7 +/- 33.4 pmol/sample; P <.05) but only by 65.6% in the animals treated with RS 312908 (416.2 +/- 120.5 pmol/sample). In contrast, hydroxyproline was not significantly affected by either elastase perfusion or drug treatment. Microscopic examination revealed the preservation of pericellular elastin and a greater degree of fibrocollagenous wall thickening after MMP inhibition, with no detectable difference in the extent of inflammation.

CONCLUSIONS

Systemic MMP inhibition suppresses aneurysmal dilatation in the elastase-induced rodent model of AAA. Consistent with its direct inhibitory effect on various MMPs, RS 132908 promotes the preservation of aortic elastin and appears to enhance a profibrotic response within the aortic wall. Hydroxamate-based MMP antagonists may therefore be useful in the development of pharmacologic approaches to the suppression of AAAs.

Analysis of the steroid binding domain of rat steroid 5alpha-reductase (isozyme-1): the steroid D-ring binding domain of 5alpha-reductase

We have previously shown that the photoactive 4-azasteroid, [1,2 3H]N-4(benzylbenzoyl)-3-oxo-4-aza-4-methyl-5alpha-androst an-17beta-carboxamide is an effective probe of rat steroid 5alpha-reductase (isozyme-1) (5alphaR-1). In the current investigation, PEG-fractionated (6.5%) detergent-solubilized preparations containing 5alphaR-1 activity were ultraviolet (UV)-photolyzed with [3H]-4MABP and subsequently purified by 8.75% preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The fractions corresponding to the radioactive peak following the dye front were analyzed by 10% sodium dodecyl sulfate-polyacrylamide gel electrophoresis and showed the presence of a single, labeled, 26 KDa protein band, the apparent molecular weight of 5alphaR-1. TCA precipitation of the labeled fractions, followed by long-term digestion of the TCA pellet with chymotrypsin and high-performance liquid chromatography analysis, indicated that the majority of the radioactivity eluted with a peak retention time of 55-56 min. Rechromatography of this fraction using a modified gradient (elution 54-55 min), followed by sequence analysis, yielded a single N-terminal tetrapeptide with the sequence, -L-E-G-F-, corresponding to residues 15-18 of the 5alphaR-1 sequence. Site-directed mutagenesis studies indicated that mutant F18L showed an approximately 12-fold increase in the Km for testosterone, whereas the Km for reduced nicotinomide adenine dinucleotide phosphate remained virtually unaltered.

Source of elastin-degrading enzymes in mycotic aortic aneurysms: bacteria or host inflammatory response?

Elastolytic matrix metalloproteinases play a central role in the development of chronic atherosclerotic aortic aneurysms, but mycotic aortic aneurysms are a distinct and unusual form of aneurysm disease caused by bacterial infection. Mycotic aortic aneurysms follow a more rapid and unpredictable course than chronic aneurysm disease and they exhibit a predilection for the suprarenal aorta, further implying unique pathophysiologic mechanisms. The purpose of this study was to examine the nature and source of elastin-degrading enzymes in mycotic aortic aneurysm. Bacterial isolates and aortic tissues were obtained from four consecutive patients undergoing surgical repair of suprarenal mycotic aortic aneurysm. Using an in vitro 3H-labeled elastin degradation assay, elastin-degrading enzyme activity was only observed in the bacteria-conditioned medium from an isolate of Pseudomonas aeruginosa. Elastin-degrading enzyme activity in the aortic tissue homogenate of this patient was abolished by the serine protease inhibitor, phenylmethylsulfonyl fluoride, but it was not suppressed by the metalloproteinase inhibitor, ethylenediamine tetraacetic acid (EDTA). In contrast, elastin-degrading enzyme activity in the bacterial-conditioned medium was decreased by about half by both phenylmethylsulfonyl fluoride and EDTA. Elastin substrate zymography revealed two phenylmethylsulfonyl fluoride-inhibitable elastin-degrading enzyme activities in the aortic tissue homogenate that corresponded to human neutrophil elastase (approximately 30 kDa) and its stable complex with alpha 1-proteinase inhibitor (approximately 80 kDa), but no activity attributable to Pseudomonas elastase, a 33-kDa metal-dependent enzyme. Human neutrophil elastase was readily detected throughout mycotic aortic aneurysm tissues by immunohistochemistry, but elastolytic metalloproteinases were only occasionally observed. The results of this study suggest that the elastin-degrading enzyme produced in mycotic aortic aneurysm are largely serine proteases of host neutrophil origin, rather than elastases produced by the infecting microorganisms or the macrophage-derived metalloproteinases typically observed in atherosclerotic aneurysm disease. Further studies will be needed to extend these findings to a larger number of patients with mycotic aortic aneurysm and those caused by additional microorganisms.

Pharmacologic suppression of experimental abdominal aortic aneurysms: acomparison of doxycycline and four chemically modified tetracyclines

BACKGROUND

Matrix metalloproteinases (MMPs) likely contribute to the degradation of medial elastin in abdominal aortic aneurysms (AAAs), and tetracycline antibiotics exhibit MMP-inhibiting properties. The purpose of this study was to compare the effects of doxycycline and several non-antibiotic chemically modified tetracyclines (CMTs) in a rat model of elastase-induced AAA.

METHODS

Fifty-two male Wistar rats underwent intraluminal perfusion of the abdominal aorta with porcine pancreatic elastase. The rats then were treated for 7 days with subcutaneous injections of saline solution, different doses of doxycycline, or 1 of 4 different CMTs. The aortic diameters were measured with microcalipers, and the fixed tissues were examined by means of light microscopy. Gelatin zymography was used to assess the MMP activity in the aortic tissue extracts.

RESULTS

The mean aortic diameter in the control group increased by 126% +/- 14% on day 7 (from 1.57 +/- 0.04 mm to 3.54 +/- 0.27 mm; P <.05), and 5 of 6 animals (83%) had AAAs. Doxycycline appeared to inhibit aortic dilatation in a dose-dependent manner, and AAAs did not develop in any animals. Half-maximal effects were observed at a dose of approximately 6 mg/kg/day, and maximal effects were noted at greater than 30 mg/kg/day. No AAAs were observed in the animals that were treated with CMTs at 15 mg/kg/day. Each of the following CMTs exhibited an efficacy that was similar to that of doxycycline (percent inhibition of aortic dilatation vs control; all P <.05): CMT-3 (47.6%), CMT-4 (38.9%), CMT-7 (47.6%), CMT-8 (54.0%), and doxycycline (51.6%). Tissues from saline solution-treated controls exhibited a transmural inflammatory response and marked destruction of the medial elastic lamellae. Tetracycline derivatives limited the disruption of medial elastin without appearing to alter either the inflammatory response or the rat aortic wall production of metallogelatinases.

CONCLUSION

Tetracycline derivatives suppress the development of AAAs after elastase-induced aortic injury in the rat. The aneurysm-suppressing effects of doxycycline appear to be dose-dependent and distinct from its antibiotic activities, and they coincide with the structural preservation of medial elastin fibers. Further studies are needed to explore the potential of MMP-inhibiting tetracyclines as a novel pharmacologic strategy for the suppression of aortic aneurysms.

[The clinical and enzymatic changes in patients with viral hepatitis G infection]

For the purpose of making sure the clinical significance of hepatitis G virus, RT-nested PCR was applied to detect HGV RNA in 165 hepatitis patients, which included 24 acute hepatitis, 78 chronic hepatitis, 18 hepatitic cirrhosis, 4 hepatocellularcarcinom and 41 HBV and HCV carriers. The results showed that the infection of HGV existed in all kinds of hepatitis patients. Among the acute hepatitis 12.5% (3/24) was HGV RNA positive. 19 (24.4%) cases were HGV RNA positive in chronic hepatitis, among which 4 cases were simply HGV RNA positive (5.13%). The serum ALT level in 3 cases of simple acute HGV patients was between 488 +/- 65 U/L, the value of AST between 452 +/- 71 U/L, the TBiL at about 77.1 +/- 14.3 mumol/L. All these showed that only HGV infection could lead to acute hepatitis. The rising enzyme dropped to normal about a month later in acute hepatitis while HGV RNA would remain. The problem whether HGV infection is caused by simple acute and chronic hepatitis infection is under investigation.

Expression and localization of macrophage elastase (matrix metalloproteinase-12) in abdominal aortic aneurysms

Elastolytic matrix metalloproteinases (MMPs) have been implicated in the pathogenesis of abdominal aortic aneurysms (AAA), a disorder characterized by chronic aortic wall inflammation and destruction of medial elastin. The purpose of this study was to determine if human macrophage elastase (HME; MMP-12) might participate in this disease. By reverse transcription-polymerase chain reaction, HME mRNA was consistently demonstrated in AAA and atherosclerotic occlusive disease (AOD) tissues (six of six), but in only one of six normal aortas. Immunoreactive proteins corresponding to proHME and two products of extracellular processing were present in seven of seven AAA tissue extracts. Total HME recovered from AAA tissue was sevenfold greater than normal aorta (P < 0.001), and the extracted enzyme exhibited activity in vitro. Production of HME was demonstrated in the media of AAA tissues by in situ hybridization and immunohistochemistry, but HME was not detected within the media of normal or AOD specimens. Importantly, immunoreactive HME was specifically localized to residual elastin fragments within the media of AAA tissue, particularly areas adjacent to nondilated normal aorta. In vitro, the fraction of MMP-12 sequestered by insoluble elastin was two- to fivefold greater than other elastases found in AAA tissue. Therefore, HME is prominently expressed by aneurysm-infiltrating macrophages within the degenerating aortic media of AAA, where it is also bound to residual elastic fiber fragments. Because elastin represents a critical component of aortic wall structure and a matrix substrate for metalloelastases, HME may have a direct and singular role in the pathogenesis of aortic aneurysms.

De novo design, synthesis, and biological activities of high-affinity and selective non-peptide agonists of the delta-opioid receptor

On the basis of the structure-activity relationships of delta-opioid-selective peptide ligands and on a model of the proposed bioactive conformation for a potent and selective, conformationally constrained delta-opioid peptide ligand [(2S, 3R)-TMT1]DPDPE, a series of small organic peptide mimetic compounds targeted for the delta-opioid receptor have been designed, synthesized, and evaluated in radiolabeled ligand binding assays and in vitro bioassays. The new non-peptide ligands use piperazine as a template to present the most important pharmacophore groups, including phenol and phenyl groups and a hydrophobic moiety. This hydrophobic group was designed to mimic the hydrophobic character of the D-Pen residues in DPDPE, which has been found to be extremely important for increasing the binding affinity and selectivity of these non-peptide ligands for the delta-opioid receptor over the mu-opioid receptor. Compound 6f (SL-3111) showed 8 nM binding affinity and over 2000-fold selectivity for the delta-opioid receptor over the mu-opioid receptor. Both enantiomers of SL-3111 were separated, and the (-)-isomer was shown to be the compound with the highest affinity for the delta-opioid receptor found in our study (IC50 = 4.1 nM), with a selectivity very similar to that observed for the racemic compound. The phenol hydroxyl group of SL-3111 turned out to be essential to maintain high affinity for the delta-opioid receptor, which also was observed in the case of the delta-opioid-selective peptide ligand DPDPE. Binding studies of SL-3111 and [p-ClPhe4]DPDPE on the cloned wild-type and mutated human delta-opioid receptors suggested that the new non-peptide ligand has a binding profile similar to that of DPDPE but different from that of (+)-4-[((alphaR)-alpha(2S,5R)-4-allyl-2, 5-dimethyl-1-piperazinyl)-3-methoxybenzyl]-N,N-diethylbenzamide (SNC-80), another delta-opioid-selective non-peptide ligand.

Therapeutic potential of tetracycline derivatives to suppress the growth of abdominal aortic aneurysms

Abdominal aortic aneurysms (AAA) represent a potentially lethal disorder associated with aging and atherosclerosis. Although current management of AAA is predicted on early detection and elective surgical repair, routine screening for AAA is infrequent, because most AAA are too small to warrant repair when first detected and because there are no therapeutic approaches proven to suppress aneurysm expansion. Basic research on this problem suggests that chronic inflammation and increased local production of elastin-degrading proteinases play prominent roles in the process of aneurysmal degeneration. Members of the matrix metalloproteinases (MMP) family appear to be the most prominent elastases produced in human AAA, suggesting that unique therapeutic targets might exist for aneurysm disease. Studies using a representative animal model for AAA support this view, providing a means for further development of pharmacological approaches to suppress aneurysm expansion. Indeed, recent work indicates that tetracycline derivatives have the potential to interrupt the progressive connective tissue destruction that occurs in AAA, by virtue of their non-antimicrobial properties as MMP inhibitors, and they do so at clinically achievable dose schedules. These findings support the view that MMPs are potentially important pharmacotherapeutic targets in AAA and, moreover, that tetracyclines might be useful in suppressing aneurysm expansion in vivo. Because tetracycline derivatives offer a number of distinct advantages as MMP inhibitors for patients with small AAA, prospective clinical trials of this novel therapeutic strategy can be anticipated in the near future.

Molecular mechanism of androgen action

Androgens affect the growth and development of a wide variety of cell types in both males and females and produce their effects by binding to androgen receptors, which modulate the transcription of specific genes. Testosterone is the major active androgen circulating in blood, but in many tissues it is metabolized by 5alpha-reductase to 5alpha-dihydrotestosterone, which binds to and activates the androgen receptor. Androgen receptors are members of the nuclear receptor family of transcription factors, and these nuclear receptors control transcription by recruitment of a variety of co-activators and co-repressors. Mutations in the androgen receptor and 5alpha-reductase can affect male sexual development. 5alpha-Reductase is also critical for parturition and fetal survival in mice. Inhibitors of 5alpha-reductase are being used increasingly to treat some androgen-dependent disorders. Because androgens also suppress the growth of certain cancer cells, they might also have a role in treating prostate cancer.

[A study on the coverage, strategy and cost of hepatitis B vaccination in China, 1996]

To understand the coverage, strategy and cost of hepatitis B (HB) vaccination of China in recent years, a randomized two-stage household sampling survey was carried out at 112 Disease Surveillance Points(DSPs) from 25 provinces, autonomous regions and municipalities of China in 1996. Results showed that the rates of HB vaccination coverage among neonates were 96.9% in the urban DSPs and 50.8% in the rural DSPs in 1993-1994, while in 7-9 year-old students both rates were 85.8% and 31.5% in 1994, respectively. Up to 1994, 97.5% of the urban DSPs and 73.9% of the rural DSPs had a neonates vaccination against HB program integrated with routine EPI. Some of the DSPs had a lower neonates coverage due to insufficient amountad unreasonable distribution of the vaccine (used for adults) and high cost. It seems necessary to evaluate the maternal prescreening program regarding the quality of serological testing to HBVMs. Remarkable achievements have been made in terms of strategy development and planning on HB immunization in China.

Progression of LNCaP prostate tumor cells during androgen deprivation: hormone-independent growth, repression of proliferation by androgen, and role for p27Kip1 in androgen-induced cell cycle arrest

The molecular mechanism of androgen-independent growth of prostate cancer after androgen ablation was explored in LNCaP cells. An androgen-dependent clonal subline of the LNCaP human prostate carcinoma cell line, LNCaP 104-S, progressed to a slow growing stage (104-R1) and then to a faster growing stage (104-R2) during more than 2 yr of continuous culture in the absence of androgen. Androgen-induced proliferation of 104-S cells is inhibited by the antiandrogen Casodex, while proliferation of 104-R1 and 104-R2 cells is unaffected by Casodex. This indicates that proliferation of 104-R1 and 104-R2 cells is not supported by low levels of androgen in the culture medium. Compared with LNCaP 104-S cells, both 104-R1 and 104-R2 cells express higher basal levels of androgen receptor (AR), and proliferation of these two cell lines is paradoxically repressed by androgen. After continuous passage in androgen-containing medium, 104-R1 cells reverted back to an androgen-dependent phenotype. The mechanism of androgenic repression of 104-R1 and 104-R2 sublines was further evaluated by examining the role of critical regulatory factors involved in the control of cell cycle progression. At concentrations that repressed growth, androgen transiently induced the expression of the cyclin-dependent kinase (cdk) inhibitor p21waf1/cip1 in 104-R1 cells, while expression of the cdk inhibitor p27Kip1 was persistently induced by androgen in both 104-R1 and 104-R2 cells. Induced expression of murine p27Kip1 in 104-R2 cells resulted in G1 arrest. Specific immunoprecipitates of Cdk2 but not Cdk4 from androgen-treated 104-R1 cells contained both p21waf1/cip1 and p27Kip1. This observation was confirmed by in vitro assay of histone H1 and Rb (retinoblastoma protein) phosphorylation by the proteins associated with the immune complex. Furthermore, inhibition of Cdk2 activity correlated with the accumulation of p27Kip1 and not p21waf1/cip1. From these results we conclude that androgenic repression of LNCaP 104-R1 and 104-R2 cell proliferation is due to the induction of p27Kip1, which in turn inhibits Cdk2, a factor critical for cell cycle progression and proliferation.

[In situ hybrid detection of p16 mRNA in primary breast carcinoma: its clinicopathologic significance]

OBJECTIVE

To investigate the expression of p16 mRNA in primary breast carcinoma and its clinicopathological significance.

METHODS

In vitro transcriptional RNA probe labeled with biotin and in situ hybridization method were used in this study to detect p16 mRNA in the paraffin embedded tissue of human primary breast carcinoma from 120 cases.

RESULTS

85 breast carcinomas showed expression of p16 mRNA with a positive rate of 70.8%. The p16 mRNA expression was not obviously correlated with patient age, tumor size, estrogen and progesterone receptor status (P > 0.05), but the positive rate of 54.4% for the lymph node metastasis group was significantly lower than 85.7% of the non-metastasis group (P < 0.001). Moreover, the positive rate of 58.3% for the poor differentiate invasive duct carcinoma was also lower than that 89.7% for the well differentiated (P < 0.05). The patients after operation were followed up. The mortality of 25% (21/85) in the p16 mRNA positive group was significantly lower than that of the negative group 57% (20/35) (P < 0.01).

CONCLUSION

Abnormal expression of p16 mRNA may play an important role in the development of human breast carcinoma.

[Long-term efficacy of plasma-derived hepatitis B vaccine among Chinese children--a 12-year follow-up]

OBJECTIVE

To evaluate protective efficacy of a plasma-derived hepatitis B vaccine during 12 years after vaccination.

METHODS

A 12-year follow-up of 350 children who participated a randomized, double blind, placebo-controlled trial in 1982.

RESULTS

During the 12 years after vaccination, more vaccinated children had anti-HBs of 10 S/N ratios or more than did the controls. At the 12 years 46.1% of the vaccinated and 33.9% of the controls retained anti-HBs levels of S/N ratios > or = 10 (P < 0.05). However, at 12 years median S/N ratio of anti-HBs of the vaccinated children with detectable anti-HBs was lower than that of the controls (15 vs 36, P < 0.0001). Protective efficacy against HBsAg carriage status at 5-10 years after vaccination varied from 83% to 100%. At 12 years, 14 chronic HBsAg carriers were identified among the controls, whereas only 1 case was noted in the vaccinated group (7.6% vs 0.6%, P < 0.01), account for an efficacy of 92%.

CONCLUSIONS

Protective efficacy against chronic HBsAg carriage was satisfactory at 12 years after vaccination. No evidence was showed to support a booster of hepatitis B vaccine at this time.

Epidermal growth factor receptor activation in androgen-independent but not androgen-stimulated growth of human prostatic carcinoma cells

These studies were undertaken to assess the relative expression and autocrine activation of the epidermal growth factor receptor (EGFR) in normal and transformed prostatic epithelial cells and to determine whether EGFR activation plays a functional role in androgen-stimulated growth of prostate cancer cells in vitro. EGFR expression was determined by Western blot analysis and ELISA immunoassays. Immunoprecipitation of radiophosphorylated EGFR and evaluation of tyrosine phosphorylation was used to assess EGFR activation. The human androgen-independent prostate cancer cell lines PC3 and DU145 exhibited higher levels of EGFR expression and autocrine phosphorylation than normal human prostatic epithelial cells or the human androgen-responsive prostate cancer cell line LNCaP. PC3 and DU145 cells also showed higher levels of autonomous growth under serum-free defined conditions. Normal prostatic epithelial cells expressed EGFR but did not exhibit detectable levels of EGFR phosphorylation when cultured in the absence of exogenous EGF. Addition of EGF stimulated EGFR phosphorylation and induced proliferation of normal cells. LNCaP cells exhibited autocrine phosphorylation of EGFR but did not undergo significant proliferation when cultured in the absence of exogenous growth factors. A biphasic growth curve was observed when LNCaP cells were cultured with dihydrotestosterone (DHT). Maximum proliferation occurred at 1 nM DHT with regression of the growth response at DHT concentrations greater than 1 nM. However, neither EGFR expression nor phosphorylation was altered in LNCaP cells after androgen stimulation. In addition, DHT-stimulated growth of LNCaP cells was not inhibited by anti-EGFR. These studies show that autocrine activation of EGFR is a common feature of prostatic carcinoma cells in contrast to normal epithelial cells. However, EGFR activation does not appear to play a functional role in androgen-stimulated growth of LNCaP cells in vitro.

[Persistence of HB vaccine immune protection and response to hepatitis B booster immunization]

OBJECTIVE

To determine the persistence of immune protection of China-made, plasma-derived HBV vaccine in infants and the time table of booster immunization.

METHODS

Serological effect of 7-year follow-up study and antibody response of an experimental study on booster were detected using radioimmunoassay.

RESULTS

The protective anti-HBs positive rates of 1,018 children, who were vaccinated according to the regimen of three doses of 10 micrograms HBV vaccine, declined from 75.0% during the first two years to 48.2% at 7 years after the first dosages, however, the positive rates for HBsAg and anti-HBc always fluctuated at low frequency. 144 children aged 6 or 7 years old, who received the HBV vaccine in their infancy and were negative for both HBsAg and anti-HBc before booster, were selected from 1,018 children of the follow-up study and boosted with 1 microgram (intradermally) or 2 micrograms (hypodemically) HBV vaccine. Their anti-HBs GMT and anti-HBs positive rate were 190.6 mIU/ml and 89.6% at one month after booster, significantly higher than 14.7 mIU/ml and 54.9% before booster (P < 0.01), and declined back to 25.3 mIU/ml and 75.5% at 12th month; among 65 children with the anti-HBs negative before booster, 40 of them had the level of anti-HBs > or = 100 mIU/ml one month after booster, suggesting the retention of immunological memory in most of them.

CONCLUSIONS

No need for revaccination against hepatitis B at 7th year after the initial immunization due to better persistence of immune protection of the vaccine.

Allele-specific adaptation of poliovirus VP1 B-C loop variants to mutant cell receptors

Previous work has shown that three different mutations in domain 1 of the poliovirus receptor (Pvr), two in the predicted C'-C" ridge and one in the D-E loop, abolish binding of the P1/Mahoney strain. All three receptor defects could be suppressed by a mutation in the VP1 B-C loop of the viral capsid that was present in all 16 P1/Mahoney isolates adapted to the mutant receptors. To identify allele-specific mutations that enable poliovirus to utilize mutant receptors, and to understand the role of the VP1 B-C loop in adaptation, we selected mutant receptor-adapted viruses derived from two P1/Mahoney variants, one which lacks the VP1 B-C loop and one in which the VP1 B-C loop is replaced with the corresponding sequence from the P2/Lansing strain. Six adapted viral isolates were obtained after passage on mutant receptor-expressing cell lines. Sequence analysis revealed that each virus contained three to five mutations, and a total of 18 amino acid changes at 17 capsid residues were identified. Site-directed mutagenesis was used to evaluate the role of these mutations in adaptation to mutant Pvr. The results demonstrate that mutations in the viral canyon floor and rim are allele specific and compensate only for receptor defects in the C'-C" ridge of Pvr, suggesting that these sites interact in the virus-receptor complex. Furthermore, mutations in the VP1 E-F loop suppressed Pvr D-E loop defects, implying that the Pvr D-E loop contacts the VP1 E-F loop. Most of the other mutations mapped to interior capsid residues, some interacting with the fivefold- or threefold-related protomers. These mutations may regulate receptor interaction by controlling the structural flexibility of the viral capsid. In viruses lacking the VP1 B-C loop, single mutations were not sufficient to confer the adapted phenotype, in contrast to the 414 virus, which contains the B-C loop. Although the VP1 B-C loop appeared to be dispensable for adaptation, it may have provided a selective advantage in adaptation of P1/Mahoney to mutant Pvr.

[AFP, uE3, beta-hCG levels applied for prenatal diagnosis of Down's syndrome]

OBJECTIVE

To investigate the relationship between fetal trisomy 21 and alpha fetoprotein (AFP), unconjugated oestriol (uE3) and beta human chorionic gonadotropin (beta-hCG) levels in maternal serum, amniotic fluid and fetal serum.

METHOD

AFP, uE3 and beta-hCG levels in maternal serum, amniotic fluid and fetal serum from 17 pregnancies with fetal trisomy 21 and 131 unaffected control pregnancies were measured between 16 to 28 weeks gestation using radioimmunoassay.

RESULTS

In these pregnancies with fetal trisomy 21, the AFP and uE3 levels in maternal serum, amniotic fluid and fetal serum were lower than those in controls; but beta-hCG levels were higher (P < 0.05).

CONCLUSION

To measure maternal serum AFP, uE3 and beta-hCG levels will be useful in prenatal detection of trisomy 21.

Preputial sebocyte 5alpha-reductase isoform specificity

We determined whether the 5alpha-reductase (5alpha-R) isozyme specificity in rat preputial sebocytes is in accordance with that of sebaceous glands (type 1 isoform) or with that of other genital tract androgen-dependent organs (type 2). Immunostaining indicated expression of type 1 5alpha-R in preputial epithelial cells in the gland as well as in culture. Northern blots and ribonuclease protection assays both showed the presence of the type 1 isozyme in preputial sebocytes, with little if any expression of the type 2 messenger RNA. Ribonuclease protection assay demonstrated that both homogenized preputial gland and freshly dispersed preputial cells express 2-fold more 5alpha-R type 1 messenger RNA than does skin and 7-fold more than cultured preputial cells. Since cultured preputial cells do not fully differentiate in monolayer culture, these findings suggest that 5alpha-R is increasingly expressed as sebaceous cells differentiate. The predominance of the type 1 isoform in preputial sebocytes is important because it indicates programming by a skin- and sebocyte-specific signal in the midst of the genital tract where the type 2 isoform otherwise predominates.

Vascular smooth muscle cell apoptosis in abdominal aortic aneurysms

Apoptosis is a naturally occurring mechanism of cell death that plays an important role in both normal and pathological remodeling of the vessel wall. Abdominal aortic aneurysms (AAA) represent a unique and dramatic example of vessel wall remodeling characterized by degeneration of the elastic media. Although much attention has been focused on the proteolytic mechanisms that underlie elastin and collagen degradation in AAA, recent studies suggest that depletion of medial smooth muscle cells (SMC) makes an important contribution to this disease by eliminating a cell population capable of directing connective tissue repair. As described in this review, these investigations have revealed that SMC depletion in human aneurysm tissues is accompanied by biochemical, morphological and molecular changes consistent with SMC apoptosis. The exact mechanisms responsible for SMC apoptosis in AAA remain to be elucidated, but current evidence indicates that elevated cellular production of p53 and p21 participates in the process. These findings provide an important new starting point for further investigations on the cellular and molecular mechanisms underlying SMC depletion in AAA and how this process might trigger the accelerated progression of aneurysm disease.

Written language production and neuropsychological function in children with traumatic brain injury

OBJECTIVE

To establish the early consequences of traumatic brain injury (TBI) on spontaneous written language production in children by examining writing deficits as a function of injury severity and correlating written performance with neuropsychological data.

DESIGN

Case-control cohort study.

SETTING

Two regional medical centers.

PATIENTS

Seventy-six children, aged 8 to 15 years, with mild, moderate, or severe closed head injury were compared with controls who were individually matched on the premorbid characteristics of age, gender, school grade, behavior, and academic performance.

MAIN OUTCOME MEASURES

Assessment of written language production and neuropsychological function was undertaken approximately 1 month following resolution of posttraumatic amnesia. Case-control differences on 16 measures of spontaneous written narratives were computed.

RESULTS

Factor analysis and conceptual similarities suggested that the measures of written language fell into five domains: Efficiency, Completeness, General Readability, Error, and Vocabulary. A highly significant, moderate correlation between these measures and severity of injury was found. The highest correlations were found for the written language domains of Efficiency and Completeness and the lowest for the Vocabulary domain. Moderate correlations were also found between measures of written language and neuropsychological function.

CONCLUSIONS

At 1 month after resolution of posttraumatic amnesia, written language production in children with TBI is negatively correlated with severity of injury. Some aspects of written language production are affected to a greater extent than others. Considerable common ground was found between written language production and neuropsychological function.

Extremely low awareness of AIDS, sexually transmitted diseases and condoms among Dai ethnic villagers in Yunnan province, China

OBJECTIVE

To assess the awareness of AIDS, other sexually transmitted diseases (STDs), condoms, sources of health information and HIV-related societal risks among Dai villagers in southern Yunnan Province, China.

SUBJECTS AND METHODS

In November-December 1994, a cross-sectional descriptive study, comprising a questionnaire-based survey and focus group discussions, was conducted in three Dai villages in Mengla county; a total of 177 Dai villagers were interviewed in the survey and eight focus group discussions were held. Ethnographic observations provided a composite picture of HIV risks in the area.

RESULTS

Only 18% of respondents had heard of AIDS, and only 25 and 28%, respectively, had heard of STDs or condoms. Furthermore, among these more aware groups, the level of knowledge was low and misconceptions were common. An ability to understand the official language (Mandarin) was the most important predictor of awareness of AIDS, other STDs or condoms. The sources of information in the three Dai villages sampled included TV, videos, radio and magazines, but only TV and videos had a large audience. Even so, these media were mostly in Mandarin and were not used in AIDS education. Travel outside of China was frequent; most villagers (77%) had traveled to Laos and 9% had traveled to Thailand. Societal risks of HIV transmission, such as an increasing incidence of STDs and an active sex industry, were observed in this area.

CONCLUSIONS

Dai villagers in southern Yunnan Province had an extremely low awareness and knowledge of AIDS, other STDs and condoms. Given the high mobility of ethnic villagers to neighboring countries in Southeast Asia and the societal risks of HIV transmission in this area, there is an urgent need to provide accessible education about AIDS and other STDs. Suggestions regarding such health education and the implications of HIV policy-making are discussed.

[Dynamic changes of serum antibody titer and liver ultrastructural pathology in acute sporadic hepatitis E virus infected patients]

7 acute hepatitis E patients were tested for anti-HEV IgM and IgG antibodies by EIA. It revealed that anti-HEV IgM and IgG antibody titers were the highest at day 10-45 of the illness, and anti-HEV IgM declined gradually and totally lost within 2 months. Anti-HEV IgG had a similar condition to anti-HEV IgM, but at 7th month there still had 3 cases (40%) remained to be antibody positive. One case was examined for ultrastructural pathology. The swelling of liver cells on the fortieth day of illness was still to be found, the vacuolation of cytoplasm and condensation of mitochondria were present in liver cells.

Growth suppression of hamster flank organs by topical application of gamma-linolenic and other fatty acid inhibitors of 5alpha-reductase

Certain unsaturated aliphatic fatty acids, such as gamma-linolenic acid, inhibit 5alpha-reductase activity in vitro and in vivo. Hamster flank organ growth, as measured by the increase in the area of pigmented macule, is dependent on androgen. When one of the paired flank organs of a castrated hamster was treated topically with testosterone, the treated organ, but not the contralateral flank organ, became larger and darker. Topical application of gamma-linolenic acid to the testosterone-treated flank organ suppressed this testosterone effect. Other fatty acids that were not inhibitors of 5alpha-reductases were not active. Topical treatment of hamster flank organs with 5alpha-dihydrotestosterone also stimulated the growth of the organ. This 5alpha-dihydrotestosterone-dependent activity, however, was not significantly affected by gamma-linolenic acid, suggesting that flank organ growth was dependent on 5alpha-dihydrotestosterone and that gamma-linolenic acid acted by inhibiting 5alpha-reductase. With intact male hamsters, the endogenous androgen-dependent growth of flank organs is also suppressed by topical treatment with gamma-linolenic acid. The effect of gamma-linolenic acid is localized at the site of its application; topical application of gamma-linolenic acid did not affect the androgen-dependent growth of other organs such as testis, epididymis, seminal vesicle, and prostate. gamma-Linolenic acid, with low toxicity and absence of systemic effect, therefore may be potentially useful for treatment of androgen-dependent skin disorders.