Developmental sensitivity of associative learning to cholesterol synthesis inhibitors

Patients with Smith-Lemli-Opitz syndrome, a genetic disorder associated with severe mental retardation, are unable to convert 7-dehydrocholesterol to cholesterol. Treatment of rats with agents that block cholesterol synthesis produces a sterol profile reminiscent of Smith-Lemli-Opitz patients i.e., low levels of cholesterol accompanied by the appearance of its immediate precursor 7-dehydrocholesterol. In previous work, chronic inhibition of cholesterol synthesis in just-weaned rats impaired acquisition of the classically conditioned eyeblink response. The present study had two primary goals--(1) to determine whether the learning impairment depended on the age in which treatment was initiated; and (2) to determine whether the deficit was associative or due to performance factors. Consistent with earlier work, acquisition of the eyeblink conditioned response was impaired when the 30-day treatment was initiated on postnatal day (PND) 21. Reactivity to acoustic stimuli and to eyelid stimulation were normal, suggesting that the learning impairment was associative in nature. The learning impairment was transitory; acquisition was normal when evaluated 30 days after the cessation of treatment. When treatment was initiated 30 days after weaning (PND 51), acquisition of the eyeblink response was normal. However, brain sterols of young adult rats were less affected than those of just-weaned rats. Thus, there is a developmental sensitivity to cholesterol synthesis blocking agents both in terms of their effects on brain sterols and new motor learning.

Determination of total N-nitroso compounds and their precursors in frankfurters, fresh meat, dried salted fish, sauces, tobacco, and tobacco smoke particulates

Total N-nitroso compounds (NOC) and NOC precursors (NOCP) were determined in extracts of food and tobacco products. Following Walters' method, NOC were decomposed to NO with refluxing HBr/HCl/HOAc/EtOAc and NO was measured by chemiluminescence. NOC were determined after sulfamic acid treatment to destroy nitrite, and NOCP were determined after treatment with 110 mM nitrite and then sulfamic acid. Analysis without HBr gave results < or =20% of those with HBr. This NOC method was efficient for nitrosamines but not nitrosoureas. The standard nitrosation for determining NOCP gave high yields for readily nitrosated amines, including 1-deoxy-1-fructosylvaline, but not for simple amines, dipeptides, and alkylureas. Mean NOC and NOCP results were (respectively, in micromol/kg of product) 5.5 and 2700 for frankfurters, 0.5 and 660 for fresh meat, 5.8 and 5800 for salted, dried fish, and 660 and 2900 for chewing tobacco (all for aqueous extracts) and 220 and 20000 nmol/cigarette for MeCN extracts of cigarette smoke filter pads.

[Effects of octreotide on implanted liver tumor after partial hepatectomy in rats]

OBJECTIVES

To investigate the effects of octreotide(OCT) on experimental live tumor after partial hepatectomy (PH) in rats and explore its intrinsic mechanism.

METHODS

Sixty-four male rats were randomly divided into four groups and operated on with laparotomy. Walker-256 tumor was implanted in all the four groups. Group A served as the control, and groups B, C and D received left lobe PH. Octreotide at a dose of 50 microg/kg was intraperitoneally (i.p.) administered twice a day in groups C and D (OCT). The time of the first administration was at the 12th hour after PH in group C and the 72nd hour after PH in group D. The rats in groups A and B received a similar volume of normal saline (NS).

RESULTS

Group A showed a significant reduction of implanted liver tumor volume at the 7th day versus group B (P < 0.01). Groups C and D showed a significant reduction of tumor volume at the 7th and 15th day versus group B (P < 0.01). The tumor cell apoptotic rate was significantly higher in groups C and D than in groups A and B at the 7th and 15th day (P < 0.01).

CONCLUSION

The growth of experimental liver tumor is enhanced after PH bat can be inhibited by OCT.

[Effect of transduction bax gene on experimental nasopharyngeal carcinoma]

OBJECTIVE

To evaluate the effect of transduction bax gene on nasopharyngeal carcinoma (NPC).

METHODS

The transduced bax gene was mediated by Dosper lipidsome to the HNE-1 cell lines, and confirmed by immunofluorescent stain. The apoptosis of the cell lines was studied by MTT stain and flow cytometry and the growth of implanted tumor in naked mouse after local injection of bax geneobserved.

RESULTS

Instantaneous expression of bax gene in HNE1 cell lines was testified by immunofluorescent stain after transduction for 48 hours, the apoptotic index were 10.7% and 69.4% for pre- and post-transduction, respectively. MTT stain showed the values of A in 490 nm after transduction to be 2.004(36 h) and 1.902(48 h). The diameter of implanted tumor mass was (1.8 +/- 0.64) cm and (3.0 +/- 0.44) cm in experimental and control groups, respectively.

CONCLUSION

The transduction bax gene can enhance the apoptosis of HNE1 cell lines and prevent growth of implanted tumor.

Association of angiotensin II type 1 receptor gene polymorphism with essential hypertension

OBJECTIVE

To determine whether the polymorphism A1166C in the angiotensin II type 1 receptor (AT1R) gene is associated with essential hypertension.

METHODS

A case-control study was carried out using 125 hypertensive and 103 normotensive subjects. The A-->C variant at position 1166 (A1166C) of the AT1R gene was identified by polymerase chain reaction (PCR) and PCR/restriction fragment length polymorphism (PCR/RFLP) analysis. The digestion products were separated on 2% agarose gels and visualized with ethidium bromide under ultraviolet ray.

RESULTS

The differences in C1166 allele frequency and in the AC genotype distribution of the AT1R gene between the hypertensive and normotensive groups were statistically significant (C allele: 0.092 vs 0.034, chi 2 = 6.186, P < 0.05; AC genotype: 0.184 vs 0.068, chi 2 = 6.654, P < 0.05).

CONCLUSION

The AC genotype is associated with essential hypertension, and the C allele may be a marker for predisposition to hypertension in Chinese Han population.

The biological effects of structural variation at the meta position of the aromatic rings and at the end of the alkenyl chain in the alkenyldiarylmethane series of non-nucleoside reverse transcriptase inhibitors

In an effort to elucidate a set of structure-activity relationships in the alkenyldiarylmethane (ADAM) series of non-nucleoside reverse transcriptase inhibitors, a number of modifications were made at two locations: (1) the meta positions of the two aromatic rings and (2) the end of the alkenyl chain. Forty-two new ADAMs were synthesized and evaluated for inhibition of the cytopathic effect of HIV-1(RF) in CEM-SS cell culture and for inhibition of HIV-1 reverse transcriptase. The size of the aromatic substituents was found to affect anti-HIV activity, with optimal activity appearing with Cl, CH(3), and Br substituents and with diminished activity occurring with smaller (H and F) or larger (I and CF(3)) substituents. The substituents at the end of the alkenyl chain were also found to influence the antiviral activity, with maximal activity associated with methyl or ethyl ester groups and with diminished activity resulting from substitution with higher esters, amides, sulfides, sulfoxides, sulfones, thioesters, acetals, ketones, carbamates, ureas, and thioureas. Twelve of the new ADAMs displayed submicromolar EC(50) values for inhibition of the cytopathic effect of HIV-1(RF) in CEM-SS cells. Selected ADAMs, 19 and 21, were compared to previously published ADAMs 15 and 17 for antiviral efficacy and activity against the HIV-1 reverse transcriptase enzyme. All four ADAMs were found to inhibit HIV-1 reverse transcriptase enzyme activity, to inhibit the replication of a variety of HIV-1 clinical isolates representing syncytium-inducing, nonsyncytium-inducing, and subtype representative isolates, and to inhibit HIV-1 replication in monocytes. Subsequent assessment against a panel of site-directed reverse transcriptase mutants in NL4-3 demonstrated no effect of the K103N mutation on antiviral efficacy and a slight enhancement (6- to 11-fold) in sensitivity to AZT-resistant viruses. Additionally, ADAMs 19 (44-fold) and 21 (29-fold) were more effective against the A98G mutation (found in association with nevirapine resistance in vitro), and ADAM 21 was 5-fold and 2-fold more potent against the Y181C inactivation mutation than the previously reported ADAMs 15 and 17, respectively. All four ADAMs were tested for efficacy against a multidrug-resistant virus derived from a highly experienced patient expressing resistance to the reverse transcriptase enzyme inhibitors AZT, ddI, 3TC, d4T, foscarnet, and nevirapine, as well as the protease inhibitors indinavir, saquinavir, and nelfinavir. ADAM 21 was 2-fold more potent than ADAM 15 and 6-fold more potent than ADAMs 17 and 19 at preventing virus replication. Thus, we have identified a novel series of reverse transcriptase inhibitors with a favorable profile of antiviral activity against the primary mutation involved in clinical failure of non-nucleoside reverse transcriptase inhibitors, K103N, and that retain activity against a multidrug-resistant virus.

Strategies for enzyme/prodrug cancer therapy

The selective activation of prodrug(s) in tumor tissues by exogenous enzyme(s) for cancer therapy can be accomplished by several ways, including gene-directed enzyme prodrug therapy (GDEPT), virus-directed enzyme prodrug therapy (VDEPT), and antibody-directed enzyme prodrug therapy (ADEPT). The central part of enzyme/prodrug cancer therapy is to deliver drug-activating enzyme gene or functional protein to tumor tissues, followed by systemic administration of a prodrug. Although each approach (GDEPT, VDEPT, and ADEPT) has been tested in clinical trials, there are some potential problems using the current delivery systems. In this article, disadvantages and advantages associated with each approach (GDEPT, VDEPT, and ADEPT) and future perspective for improving current systems are discussed.

Mutations in the cytoplasmic domain of P0 reveal a role for PKC-mediated phosphorylation in adhesion and myelination

Mutations in P0 (MPZ), the major myelin protein of the peripheral nervous system, cause the inherited demyelinating neuropathy Charcot-Marie-Tooth disease type 1B. P0 is a member of the immunoglobulin superfamily and functions as a homophilic adhesion molecule. We now show that point mutations in the cytoplasmic domain that modify a PKC target motif (RSTK) or an adjacent serine residue abolish P0 adhesion function and can cause peripheral neuropathy in humans. Consistent with these data, PKCalpha along with the PKC binding protein RACK1 are immunoprecipitated with wild-type P0, and inhibition of PKC activity abolishes P0-mediated adhesion. Point mutations in the RSTK target site that abolish adhesion do not alter the association of PKC with P0; however, deletion of a 14 amino acid region, which includes the RSTK motif, does abolish the association. Thus, the interaction of PKCalpha with the cytoplasmic domain of P0 is independent of specific target residues but is dependent on a nearby sequence. We conclude that PKC-mediated phosphorylation of specific residues within the cytoplasmic domain of P0 is necessary for P0-mediated adhesion, and alteration of this process can cause demyelinating neuropathy in humans.

Hyper-expression of human apolipoprotein E4 in astroglia and neurons does not enhance amyloid deposition in transgenic mice

Recent studies in mice have clearly demonstrated that eliminating Apo E alters the rate, character and distribution of A beta deposits. In the present study, we asked whether elevating the levels of Apo E can, in a dominant fashion, influence amyloid deposition. We expressed human (Hu) Apo E4 via the mouse prion protein promoter, resulting in high expression in both astrocytes and neurons; only astrocytes efficiently secreted Hu Apo E4 (at least 5-fold more than endogenous). Mice hyper-expressing Hu Apo E4 developed normally and lived normal lifespans. The co-expression of Hu Apo E4 with a mutant amyloid precursor protein (APP) (Mo/Hu APPswe) or mutant APP and mutant presenilin (PS1dE9) did not lead to proportional changes in the age of appearance, relative burden, character or distribution of A beta deposits. We suggest that these data are best explained by proposing that the mechanisms by which Apo E influences A beta deposition involves an aspect of its normal function that is not augmented by hyper-expression.

Determination of arsenic species by capillary zone electrophoresis with large-volume field-amplified stacking injection

Determination of arsenic species by large-volume field amplified stacking injection-capillary zone electrophoresis (LV-FASI-CZE) is reported in this paper. Whole column injection was employed. The optimum buffer pH for the separation of weak acids was discussed. It was found that the optimum buffer to analyze the stacked arsenate (As(V)), monomethylarsonate (MMA), and dimethylarsinate (DMA) was 25 mM phosphate at pH 6.5. However, the optimum buffer to analyze the concentrated arsenite (As(III)) was 20 mM phosphate - 10 mM borate at pH 9.28. The limits of detection of the method developed were 0.026 mg/L for As(III), 0.023 mg/L for As(V), 0.043 mg/L for MMA, and 0.018 mg/L for DMA. An enrichment factor of 34-100 for several arsenic species was obtained. In the end, this method was applied to determine the arsenic concentration in the environmental reference materials to show the usefulness of the method developed.

The anabolic activity of bone tissue, suppressed by disuse, is normalized by brief exposure to extremely low-magnitude mechanical stimuli

It is generally believed that mechanical signals must be large in order to be anabolic to bone tissue. Recent evidence indicates, however, that extremely low-magnitude (<10 microstrain) mechanical signals readily stimulate bone formation if induced at a high frequency. We examined the ability of extremely low-magnitude, high-frequency mechanical signals to restore anabolic bone cell activity inhibited by disuse. Adult female rats were randomly assigned to six groups: baseline control, age-matched control, mechanically stimulated for 10 min/day, disuse (hind limb suspension), disuse interrupted by 10 min/day of weight bearing, and disuse interrupted by 10 min/day of mechanical stimulation. After a 28 day protocol, bone formation rates (BFR) in the proximal tibia of mechanically stimulated rats increased compared with age-matched control (+97%). Disuse alone reduced BFR (-92%), a suppression only slightly curbed when disuse was interrupted by 10 min of weight bearing (-61%). In contrast, disuse interrupted by 10 min per day of low-level mechanical intervention normalized BFR to values seen in age-matched controls. This work indicates that this noninvasive, extremely low-level stimulus may provide an effective biomechanical intervention for the bone loss that plagues long-term space flight, bed rest, or immobilization caused by paralysis.

Cytochrome c release is upstream to activation of caspase-9, caspase-8, and caspase-3 in the enhanced apoptosis of anaplastic thyroid cancer cells induced by manumycin and paclitaxel

We previously demonstrated that the combination of a farnesyltransferase inhibitor, manumycin A, and paclitaxel had a synergistic antineoplastic effect on anaplastic thyroid cancer. In this study we investigated the apoptosis pathway involved. In ARO and KAT-4 cells, manumycin- plus paclitaxel-induced DNA fragmentation was blocked by the inhibitors of caspase-9, caspase-8, and caspase-3. The drug combination enhanced the activation of caspase-9, caspase-8, and caspase-3 and cytochrome c release into the cytosol. Cytochrome c release was not affected by the inhibitors of caspase-9, caspase-8 and caspase-3. In a cell-free reconstitution assay, DNA fragmentation occurred after incubating nuclei purified from untreated KAT-4 cells with deoxy-ATP, exogenous cytochrome c and S-100 extracts from control KAT-4 cells, and also after incubation of purified KAT-4 nuclei with S-100 extracts from KAT-4 cells treated with manumycin-plus-paclitaxel. In both cases, the DNA fragmentation was blocked by the inhibitors of caspase-9, caspase-8 and caspase-3. We concluded that the cytochrome c release was upstream of the activation of caspase-9, caspase-8, and caspase-3 in the enhanced apoptosis of anaplastic thyroid cancer cells treated with manumycin plus paclitaxel, and that the interaction between manumycin and paclitaxel occurred at or upstream of cytochrome c in the apoptosis regulatory pathway in anaplastic thyroid cancer cells.

Altered immediate early gene expression in injured diabetic nerve: implications in regeneration

To study the role that immediate early gene responses may play in impaired nerve fiber regeneration in diabetes, diabetic male BB/Wor rats were subjected to sciatic nerve crush at 6 wk of diabetes. Sciatic nerve mRNA expression of IGF-I, IGF-1-receptor, NGF, and p75 (low affinity NGF receptor), as well as protein expression of C-FOS, were examined at various time points following crush injury and compared with age- and sex-matched nondiabetic BB/Wor rats. Diabetic rats showed a delay in the early peak expression of IGF-1, C-FOS, NGF, and p75. The earliest immediate gene responses were those of IGF-I and IGF-1-receptor, which peaked at 0.5 h post-crush in control rats. In diabetic rats, IGF-1 peaked at 24 h whereas IGF-1-receptor mRNA revealed no early peak. The early NGF mRNA expression showed a maximum response at 6 h and of p75 at 4 days post-crush in control rats, whereas in diabetic rats they occurred at 2 days and 6 days, respectively. C-FOS protein expression showed a maximum at 6 h in control rats and in diabetic animals an attenuated peak was present at 2 days. These data provide the first evidence that immediate early gene responses are delayed in diabetes following sciatic nerve crush injury. The delayed IGF-1 expression may affect C-FOS induction and may be responsible for the delay in the NGF response in diabetic rats. The delayed immediate early gene responses precede the previously described perturbed macrophage recruitment and delayed Wallerian degeneration in this type I model and provide a possible explanation for impaired nerve regeneration in diabetes.

[Surgery of substernal goiter]

OBJECTIVE

To study the surgical approaches and operative techniques for substernal goiter.

METHOD

A retrospective study of 27 cases with substernal thyroid nodules was made in our hospital.

RESULT

The operations on 27 patients with substernal nodules have been successfully carried out. Among them, 10 were goiters, 9 adenomas, 4 malignancy and 4 were thyroid cancer metastasizing to paratracheal or substernal nodes. Resection via cervical collar incision was adequate in 23 cases. Three thyroid cancers with paratracheal node metastasis were completely resected by sternotomy and only one thyroid cancer with paratracheal and substernal nodes metastasis was resected by combined thoracotomy and cervical collar incision.

CONCLUSION

Resection via cervical collar incision for all retrosternal thyroid nodules were advised. The preliminary experience with this procedure suggests that it has some advantages in the management of substernal goiter, including: 1. ease of operation compared to both sternotomy and thoracotomy; 2. relatively low morbidity; 3. safe and reliable.

Application of analytical and preparative high-speed counter-current chromatography for separation of lycopene from crude extract of tomato paste

Lycopene was isolated from 100 mg of crude extract of tomato paste containing about 9% of lycopene. Analytical high-speed counter-current chromatography (HSCCC) was first used for the systematic selection of the two-phase solvent system. Then preparative HSCCC separation was performed with a nonaqueous solvent system composed of n-hexane-dichloromethane-acetonitrile at an optimum volume ratio of 10:3.5:6.5. This yielded 8.6 mg of lycopene at over 98.5% purity as determined by HPLC analysis.

7-Dehydrocholesterol-dependent proteolysis of HMG-CoA reductase suppresses sterol biosynthesis in a mouse model of Smith-Lemli-Opitz/RSH syndrome

Smith-Lemli-Opitz/RSH syndrome (SLOS), a relatively common birth-defect mental-retardation syndrome, is caused by mutations in DHCR7, whose product catalyzes an obligate step in cholesterol biosynthesis, the conversion of 7-dehydrocholesterol to cholesterol. A null mutation in the murine Dhcr7 causes an identical biochemical defect to that seen in SLOS, including markedly reduced tissue cholesterol and total sterol levels, and 30- to 40-fold elevated concentrations of 7-dehydrocholesterol. Prenatal lethality was not noted, but newborn homozygotes breathed with difficulty, did not suckle, and died soon after birth with immature lungs, enlarged bladders, and, frequently, cleft palates. Despite reduced sterol concentrations in Dhcr7(-/-) mice, mRNA levels for 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, the rate-controlling enzyme for sterol biosynthesis, the LDL receptor, and SREBP-2 appeared neither elevated nor repressed. In contrast to mRNA, protein levels and activities of HMG-CoA reductase were markedly reduced. Consistent with this finding, 7-dehydrocholesterol accelerates proteolysis of HMG-CoA reductase while sparing other key proteins. These results demonstrate that in mice without Dhcr7 activity, accumulated 7-dehydrocholesterol suppresses sterol biosynthesis posttranslationally. This effect might exacerbate abnormal development in SLOS by increasing the fetal cholesterol deficiency.

Expression of TGF-beta signaling genes in the normal, premalignant, and malignant human trophoblast: loss of smad3 in choriocarcinoma cells

We had earlier shown that TGF-beta controls proliferation, migration, and invasiveness of normal human trophoblast cells, whereas premalignant and malignant trophoblast cells are resistant to TGF-beta. To identify signaling defects responsible for TGF-beta resistance in premalignant and malignant trophoblasts, we have compared the expression of TGF-beta signaling molecules in a normal trophoblast cell line (HTR-8), its premalignant derivative (RSVT2/C), and two choriocarcinoma cell lines (JAR and JEG-3). RT-PCR analysis revealed that all these cell lines expressed the mRNA of TGF-beta1, -beta2, and -beta3, TGF-beta receptors type I, II, and III, and post-receptor signaling genes smad2, smad3, smad4, smad6, and smad7 with the exception that TGF-beta2 and smad3 were undetectable in JAR and JEG-3 cells. Immunoblot analysis confirmed the absence of smad3 protein in choriocarcinoma cells. Treatment with TGF-beta1 induced smad3 phosphorylation and smad3 translocation to the nucleus in the normal and premalignant trophoblast cells. These results suggest that loss of smad3 may account for a functional disruption in the TGF-beta signaling pathway in choriocarcinomas, but not in the premalignant trophoblast.

Changes in coagulation and tissue plasminogen activator after the treatment of cerebral infarction with lumbrokinase

This paper aimed to investigate the effect of lumbrokinase on the anticoagulation and fibrinolysis in treating cerebral infarction. Lumbrokinase was used in patients with cerebral infarction. Patients were randomly divided into treatment group (n = 31) and control group (n = 20). Single blind method was used in this investigation. The Chinese stroke score was used to evaluate the results of treatment before and after administration of lumbrokinase. Kaolin partial thromboplastin time (KPTT), prothrombin time (PT), fibrinogen content, vWF content were analyzed, and tissue plasminogen activator (t-PA) activity, plasminogen activator inhibitor (PAI) activity, D-dimer level were assayed. In both groups, the stroke score decreased after administration, but in the treatment group, it was more obvious. In the treatment group, KPTT was prolonged, t-PA activity and D-dimer level increased, while the content of fibrinogen decreased significantly. There were no significant changes of PT and PAI activity in both groups. It is concluded that lumbrokinase is beneficial to the treatment of cerebral infarction. The effect of lumbrokinase is related to the inhibition of intrinsic coagulation pathway and the activation of fibrinolysis via an increase of t-PA activity.

Side chain hydroxylations in bile acid biosynthesis catalyzed by CYP3A are markedly up-regulated in Cyp27-/- mice but not in cerebrotendinous xanthomatosis

The accumulation of various 25-hydroxylated C(27)-bile alcohols in blood and their excretion in urine are characteristic features of cerebrotendinous xanthomatosis (CTX) a recessively inherited inborn error of bile acid synthesis caused by mutations in the mitochondrial sterol 27-hydroxylase (CYP27) gene. These bile alcohols may be intermediates in the alternative cholic acid side chain cleavage pathway. The present study was undertaken to identify enzymes and reactions responsible for the formation of these bile alcohols and to explain why Cyp27(-/-) mice do not show CTX-related abnormalities. Microsomal activities of 5beta-cholestane-3alpha,7alpha,12alpha-triol 25- and 26-hydroxylases, 5beta-cholestane-3alpha,7alpha,12alpha,25-tetrol 23R-, 24S-, and 27-hydroxylases and testosterone 6beta-hydroxylase, a marker enzyme for CYP3A, in Cyp27(-/-) mice livers were markedly up-regulated (5.5-, 3.5-, 6.5-, 7.5-, 2.9-, and 5.4-fold, respectively). In contrast, these enzyme activities were not increased in CTX. The activities of 5beta-cholestane-3alpha,7alpha,12alpha-triol 25- and 26-hydroxylases and 5beta-cholestane-3alpha,7alpha,12alpha,25-tetrol 23R-, 24R-, 24S-, and 27-hydroxylases were strongly correlated with the activities of testosterone 6beta-hydroxylase in control human liver microsomes from eight unrelated donors. Troleandomycin, a specific inhibitor of CYP3A, markedly suppressed these microsomal side chain hydroxylations in both mouse and human livers in a dose-dependent manner. In addition, experiments using recombinant overexpressed human CYP3A4 confirmed that these microsomal side chain hydroxylations were catalyzed by a single enzyme, CYP3A4. The results demonstrate that microsomal 25- and 26-hydroxylations of 5beta-cholestane-3alpha,7alpha,12alpha-triol and microsomal 23R-, 24R-, 24S-, and 27-hydroxylations of 5beta-cholestane-3alpha,7alpha,12alpha,25-tetrol are mainly catalyzed by CYP3A in both mice and humans. Unlike Cyp27(-/-) mice, CYP3A activity was not up-regulated despite marked accumulation of 5beta-cholestane-3alpha,7alpha,12alpha-triol in CTX.

Solid-phase synthesis of the alkenyldiarylmethane (ADAM) series of non-nucleoside HIV-1 reverse transcriptase inhibitors

The Sonogashira and Stille cross-coupling reactions have been employed in the synthesis of several non-nucleoside reverse transcriptase inhibitors (NNRTIs) in the alkenyldiarylmethane (ADAM) series. The synthesis has been carried out both in solution and on a solid support. In contrast to previous syntheses of NNRTIs in the ADAM series, the present strategy allows the incorporation of differently substituted aromatic rings in a stereochemically defined fashion. The most potent of the new ADAMs inhibited the cytopathic effect of HIV-1RF in CEM-SS cell culture with an EC50 value of 20 nM.

Fractionated stereotactic radiosurgery for 50 patients with recurrent or residual nasopharyngeal carcinoma

PURPOSE

This study was conducted to evaluate the clinical value of fractionated stereotactic radiosurgery (FSRS) as a boost treatment in 44 patients with residual or recurrent nasopharyngeal carcinoma after conventional radiotherapy (70-80 Gy) or a second course of radiotherapy (50 Gy) or as salvage treatment in 6 patients with recurrent nasopharyngeal carcinoma after a first or second course of radiotherapy at the primary site.

METHODS AND MATERIALS

From September 20, 1995 to December 30, 1998, 50 patients were treated with FSRS with 6 MV of photons. The total FSRS dose was 14-35 Gy (median dose 24) prescribed at 1-4 centers on the 60-90% isodose curves normalized to the isocenter by multiple fractions of 6-8, 12, or 15 Gy, with interfraction intervals of 4-6 days.

RESULTS

Thirty-eight patients (76%) had a complete tumor response, 9 (18%) had a partial response, and 3 (6%) were not assessable. The overall rate of survival was 83.6% at 1 year, 65.0% at 2 years, and 59.6% at 3 years. The overall disease-free survival rate among patients with residual tumor was 89.94% at 1 year, 73.97% at 2 years, and 73.97% at 3 years. Patients who were treated for recurrent lesions or who received FSRS as salvage therapy had a 46.53% rate of disease-free survival at both 1 and 2 years after therapy.

CONCLUSION

FSRS is strongly indicated for recurrent or residual nasopharyngeal carcinoma at the primary site.

[Clinical application of the reversed digital arteial island flap with digital wein and digital dorsal nerve anastomosis]

OBJECTIVE

To introduce clinical application of the reversed digital arteial island flap with digital wein and digital dorsal nerve anastomosis to repair digital soft tissue defect.

METHODS

Since 1999, 10 cases involving 14 digital defects associated with exposure of bone or tendon were treated by using the reversed digital arterial island flap with digital vein and digital dorsal cutaneous nerves anastomosis.

RESULTS

All the flaps were 100% survived and the result is satisfactory.

CONCLUSIONS

The reversed digital arterial island flap with anastomosing the digital vein and dorsa digita nerve is a safe, and simple technique, which can maintain the finger's normal appearance and reduce the incidence of venous crisis and improve the survival rate of the flap.

Plant stanol fatty acid esters inhibit cholesterol absorption and hepatic hydroxymethyl glutaryl coenzyme A reductase activity to reduce plasma levels in rabbits

The aim of this study was to study the inhibitory effect of dietary stanols (campestanol and sitostanol) fatty acid esters (SE) on intestinal cholesterol absorption. New Zealand white rabbits were fed regular chow alone or enriched with 0.2% cholesterol, 0.33% SE + cholesterol, 0.66% SE + cholesterol, 1.2% SE + cholesterol, 2.4% SE + cholesterol, and 1.2% SE alone. After 2 weeks, plasma cholesterol levels increased 3.6 times in the cholesterol group and did not decrease after addition of 0.33% or 0.66% SE to the cholesterol-enriched diets. However, after addition of 1.2% SE to the cholesterol diet, plasma cholesterol concentration decreased 50% (P <.001), but it did not decrease further after doubling of SE to 2.4%. Percent cholesterol absorption measured by the plasma dual-isotope ratio method was 73.0% +/- 8.1 % in the cholesterol group, which was similar to untreated baseline control. The percent absorption of cholesterol did not decrease significantly after addition of 0.33% or 0.66% SE to the cholesterol diet but decreased 43.8% (P <.001) in the 1.2% SE + cholesterol group, a finding similar to those in rabbits fed 1.2% SE alone. Increasing SE to 2.4% in the cholesterol diet did not further decrease absorption. Hepatic hydroxymethyl glutaryl coenzyme A (HMG-CoA) reductase activity reflecting cholesterol synthesis and low-density lipoprotein receptor-mediated binding unexpectedly decreased 67% (P <.01) and 57% (P <.05) in rabbits fed 1.2% SE alone. Increasing dietary SE intake to 1.2% reduced cholesterol absorption and plasma levels. Dietary SE intake below 1.2% was ineffective and above 2.4% did not further decrease percent absorption or plasma cholesterol levels. These results support the hypothesis that dietary SEs competitively displace cholesterol from intestinal micelles to reduce cholesterol absorption and decrease plasma cholesterol levels.