[The long-term effect of double embolization of bronchial artery on patients with hemoptysis]

OBJECTIVE

To investigate the long-term effect of bronchial arterial embolization with different material and procedure on patients with hemoptysis.

METHOD

Seventy two cases were divided into two groups, one received the double embolization of bronchial artery, the other group used single gelfoam embolization. In double embolization group, the mixture containing gelfoam microspheres (0.5 mm x 0.5 mm), erythromycin and high osmalality sodium chloride were firstly used to embolize the terminal vessels, the gelfoam particle (1 mm x 1 mm) was then used to embolize the main trunk of bronchial artery.

RESULT

After 2-4.8 years following up, it turned out that the cure rate and general effectiveness were: the double embolization group 83%, 100% respectively, the single gelfoam embolization group 61%, 95%. By comparison, there were significant difference on cure rate between these two groups(P < 0.05).

CONCLUSION

The bronchial arterial double embolization will increase the long-term effect obviously on patients with hemoptysis.

Target-specific morphology of retinal axon arbors in the adult hamster

The B fragment of cholera toxin (CT-B) provides a highly sensitive anterograde tracer for labeling retinofugal axons, revealing dense projections to known central retinorecipient nuclei, and sparse but distinct inputs to regions that have not been traditionally recognized as targets of direct retinal projections. In hamsters, we can identify CT-B labeled retinal axons in more than 25 cell groups in the mesencephalon, diencephalon, and basal telencephalon. CT-B labeling additionally delineates the complete arbor morphology, especially in regions that receive a sparse input, offering hitherto unknown views of retinal axon ramifications. We present here the terminal morphology of retinal axons in the lateral geniculate body and superior colliculus, verifying earlier studies, and also document novel findings on the configuration of retinal axon endings in the ventral nucleus of the lateral geniculate body, intergeniculate leaflet, suprachiasmatic nucleus, and in the nuclei of the accessory optic tract. Additionally, the trajectory and terminal morphology of retinal afferents to the hypothalamus, preoptic area, and basal telencephalon are detailed. The results are discussed in the context of possible functional roles for some of these projections.

[Effect of Sisheng Decoction on repairing function of DNA in mice splenic lymphocytes]

OBJECTIVE

To explore the mechanism of alleviating the side effects of irradiation by Sisheng Decoction (SSD).

METHODS

The mice splenic lymphocytes were treated by hydroxylurea to stop the DNA replication in S stage, irradiated by ultraviolet ray (UV) and the 3H TdR was added into the cultural medium. After the lymphocytes were cultured in 37 degrees C for 4 h, the capacity for 3H-TdR in the lymphocytes were tested. The effect of SSD in different content on the cut and patch repair(CPR) of DNA can be inferred by observing the lymphocyte uptake index (LUI) of 3H-TdR.

RESULTS

LUI of mice spleen lymphocytes could be increased by pretreating the lymphocytes with SSD for 4 h and then irradiated by UV, but it could not be increased if the lymphocytes were treated by SSD and UV at the same time.

CONCLUSION

SSD can alleviate the side effect of irradiation by enhancing the function of CPR-DNA, which need pretreating the lymphocytes with SSD.

Target- as well as source-derived factors direct the morphogenesis of anomalous retino-thalamic projections

Neonatal tectal lesions in hamsters result in the elimination of a major central target of retinal axons, massively denervate the lateral posterior nucleus of the thalamus (LP), and lead to a marked increase of the retino-LP projection. In such animals, retino-LP axons show all of the normally-occurring terminal types. In addition, large clusters of varicosities, whose tubular configuration resembles the major type of tecto-LP terminals observed in normal animals, are also noted if the tectal lesion is made on the day after birth (P1). If, however, the neonatal lesion occurs on P5 rather than on P1, terminals resembling normal tecto-LP endings are rarely observed; rather, the distribution and morphology of retino-LP terminals bear a greater resemblance to those seen in normal hamsters, but the size and complexity of the terminals, particularly those that form string-like arrangements, is significantly increased. Our findings suggest that the altered morphology of some abnormally induced retino-LP terminals may be orchestrated by target-associated signals. However, there are age-related limitations on the degree to which afferent systems can vary their terminal morphology; these restrictions may derive from the target, or may be a function of intrinsic changes within the cells of origin of the afferent fibers.

Afferents from the colliculus, cortex, and retina have distinct terminal morphologies in the lateral posterior thalamic nucleus

We have examined the morphology of afferent endings that originate in three distinct cell groups and terminate in the lateral posterior nucleus of the thalamus (LP). Retino-LP projections were sparse, occurred throughout the nucleus, and could be classified into 1) simple en passant varicosities and terminal swellings found on poorly branched fibers in all LP subdivisions, 2) string-like configurations of varicosities detected largely in the medial subdivision of the LP, and 3) terminals resembling retinogeniculate endings occurring mainly in the rostral part of the superficial subdivision of the LP adjacent to the dorsal nucleus of the lateral geniculate body. Cortico-LP terminals fell into three classes: 1) single varicosities decorating the tips of short appendages on fine preterminal and terminal axons; 2) tiny, round varicosities studding the axon shaft; and 3) boutons of variable shape visible on medium-caliber corticothalamic fibers. Tecto-LP terminals exhibited a large variation in morphology and density. Those found most commonly could be classified into two groups: 1) individual swellings and 2) terminal clusters arranged in a tubular configuration that enclosed a central channel, most likely occupied by the dendrite of a postsynaptic neuron. An unusual tecto-LP terminal consisted of an ovoid swelling (up to 20 microns in the long axis) from which emerged several long, thin extensions and was seen at the tips of large-diameter axons. These results show that, despite having overlapping projection zones, each set of afferents that projects to the LP elaborates terminal specializations that are structurally distinct from others projecting to the same target area.

A dominant negative mutation in Saccharomyces cerevisiae methionine aminopeptidase-1 affects catalysis and interferes with the function of methionine aminopeptidase-2

Methionine aminopeptidase (MetAP) enzymes require the metal ion cobalt, but little is known about the role of cobalt in the structural stability or catalysis of these enzymes. In Escherichia coli MetAP, for which a crystal structure is available, the five amino acid residues liganding the two cobalt ions are Asp97, Asp108, His171, Glu204, and Glu235. These five amino acids are conserved in all MetAPs sequenced to date. The C-terminal domain of the yeast Saccharomyces cerevisiae MetAP1 is 41% identical to E. coli MetAP and contains these cobalt coordinating residues. Using site-directed mutagenesis on the gene coding for yeast MetAP1, we replaced Asp219 (corresponding to Asp97 in E. coli MetAP) with Asn. The yeast D219N mutant enzyme has 10(3)-fold lower catalytic activity and a different substrate specificity when compared to wild-type yeast MetAP1. These results indicate that the side-chain of Asp219 is important for catalysis. Expression of D219N-MetAP1 in yeast causes a slow-growth phenotype and interferes with wild-type MetAP1 in a dominant manner. Expression of D219N-MetAP1 also affects the function of S. cerevisiae MetAP2.

Currycombs for the vaginal paravaginal defect repair

BACKGROUND

The paravaginal defect, present in more than three-quarters of patients with cystoceles, can be repaired by both the abdominal and vaginal approaches. The technical challenges of the vaginal paravaginal repair have militated against its widespread adoption by gynecologic surgeons.

INSTRUMENT

Currycombs can be used to facilitate suture management during vaginal paravaginal repair.

EXPERIENCE

The vaginal paravaginal repair using currycombs was performed as part of pelvic repair surgery on 27 patients. Perioperative complications were minimal. A cystocele cure rate of 80% was achieved after a mean follow-up of 8 months.

CONCLUSION

The use of currycombs during performance of the vaginal paravaginal repair facilitates suture management. The addition of this technique should help gynecologic surgeons to perform this somewhat daunting surgical procedure.

Neurogenesis in juvenile and adult ring doves

Studies in songbirds suggest that neurogenesis during the first few years of life is related to song learning. In this study, we examined whether postnatal neurogenesis occurs in a nonsongbird, the ring dove (Streptoplia risoria), and whether it persists to old age. Twenty-four hours after a single intramuscular injection of [3H]thymidine, labeled cells were present in the brains, particularly in the lateral wall of the lateral ventricle of juvenile (3-month and 8-month) and adult (1-year to 8-year) doves. Two months after multiple [3H]thymidine injections, there were fewer labeled cells in the ventricular zone (VZ), but many labeled cells with neuronal morphology in the parenchyma of the forebrain; labeled cells were confirmed as neurons by using neuron-specific markers, microtubule-associated protein-2 (MAP-2) and anti-neuronal nucleus (NeuN). In general, new neurons were distributed in the forebrain without clustering in any particular nucleus. During the first year of life, however, neostriatum caudale and hyperstriatum, the regions known to be essential for proper integration of sensory cues and reproductive behavior, contained more new neurons than any other brain regions. These neuronal additions showed an age-related decline; the first reduction coincided with the dove's attainment of adult physical size (about 3 months old) and the second occurred when the dove would normally attain reproductive fitness (about 1 year old). A low level of forebrain neurogenesis persisted up to 8 years of age (the oldest animals studied). These observations suggest that neurogenesis in adulthood is widespread among birds but that the biological significance of adult neurogenesis in the ring dove remains to be determined.

'Creeping' cytomegalovirus retinitis in AIDS

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[The prospective study of trial labor following previous cesarean section]

OBJECTIVE

To investigate the trial of labor following previous cesarean section.

METHODS

Three hundred and sixty one cases of pregnant women with history of previous low segment transverse cesarean section were prospectively studied on mode of delivery. 158 cases delivered by elective repeat cesarean section. 203 cases were allowed a trial of labor.

RESULTS

183 out of 203 patients had successful vaginal deliveries. One patient with uterine scar partly ruptured was noted on uterine exploration after delivery. There was no maternal death. The rate of spontaneous vaginal delivery was 79.2%. The rate of vacuum extractor and low forceps deliveries was 20.8%. The 1 minute Apgar score of 170 newborns was > or = 8. Neonatal asphyxia was found in 13 newborns and there was one neonatal death due to congenital abnormality.

CONCLUSIONS

Carefully selecting the indication of trial labor and monitoring the labor course are very important for increasing successful vaginal delivery rate and reducing repeat cesarean section.

Fragmentation of therapeutic human immunoglobulin preparations

Some commercial batches of human therapeutic immunoglobulins (Ig) have been found to show evidence of molecular fragmentation when examined by molecular sizing methodologies including sodium dodecyl sulphate polyacrylamide gel electrophoresis [SDS-PAGE] and size exclusion high performance liquid chromatography (SE-HPLC). These batches all demonstrated impaired immunobiological activity (efficacy) as assessed by Fc function measured using a rubella haemolytic assay and as such are likely to be subpotent for therapeutic use. Fragmented Igs were characterized by the presence of at least three protein bands and peaks additional to monomeric IgG. Incubation of Igs with blood enzymes (plasmin and kallikrein) reproduced the fragmentation patterns observed for intrinsically degraded batches, suggesting that fragmentation occurred by contamination with these proteases from the source material (human blood) during manufacture. Intravenous Igs (IVIG) were found to be more susceptible to proteolysis than intramuscular Igs, probably as a consequence of the post-fractionation processing that some IVIGs receive which may induce molecular alterations, allowing enzyme access and fragmentation. Two of the products examined were found to be relatively resistant to proteolysis and both were formulated by processes that limit enzyme activity. These processes were inclusion of an enzyme inhibitor, alpha 2-macroglobulin, and formulation at acidic pH. Enzyme carry-over into the final product is a likely cause of Ig fragmentation, and reduction in levels of such contamination should lead to improvements in product stability and efficacy.

Treatment planning structure and process in the United States: a "Patterns of Care" study

PURPOSE

To conduct a study of the structure and process of treatment planning in the United States.

METHODS AND MATERIALS

A Patterns of Care treatment planning consensus committee developed a survey form that was used to gather data for 106 items relating to the structure and process of treatment planning. These questions were general in nature and not specific to any particular disease site. Seventy-three facilities were randomly selected for site visits from the 1321 radiation therapy facilities in the United States: 21 academic, 26 hospital, and 26 free-standing. During the site visit the facility physicist, assisted by the site-visit physicist, completed the form.

RESULTS

Twenty-nine percent of facilities have cobalt-60 machines; 25% have 4 MV linacs; 75% have photon energies in the range of 5-8 MV; and less than 10% have energies greater than 20 MV. Academic facilities led hospital and free-standing facilities by about 30 percentage points in the availability of all electron energies (88 vs. 58%, approximately, in the range 4-13 MeV and scaling downward to about 60 vs. 30% at the highest energies). The national averages for the availability of Cs-137, Ir-192, and I-125 were 87, 73, and 44%, respectively. Computerized tomography (CT) scanning is not available or not used in 15% of hospital and free-standing facilities. Ninety-six percent of facilities have treatment planning computers; at 10% of facilities physicians do not participate in treatment planning. The estimated national averages of facilities having formal quality assurance (QA) programs for treatment planning systems, simulators, film processors, and blocking systems are 44, 79, 62, and 55%, respectively. Sixty-three percent of facilities obtain independent machine calibrations.

CONCLUSION

This is the first patterns of treatment planning study carried out in the United States and the results reported here will establish a baseline for future studies. The present study has identified some elements that were unexpected, such as the percentage of facilities lacking formal QA programs for treatment planning systems; however, it has not established any impact of such findings. It is recommended that future studies include the availability of new technologies such as multileaf collimation, dynamic wedges, digital portal imaging, and CT simulation. With the increasing nationwide concern with the cost of health care, we must continue to monitor the implementation, use, and impact on treatment outcome of new and expensive technologies.

Evidence that two zinc fingers in the methionine aminopeptidase from Saccharomyces cerevisiae are important for normal growth

Limited proteolysis of intact yeast methionine aminopeptidase (MAP1) with trypsin releases a 34 kDa fragment whose NH2-terminal sequence begins at Asp70, immediately following Lys69. These results suggest that yeast MAP may have a two-domain structure consisting of an NH2-terminal zinc finger domain and a C-terminal catalytic domain. To test this, a mutant MAP lacking residues 2-69 was generated, overexpressed, purified and analyzed. Metal ion analyses indicate that 1 mol of wild-type yeast MAP contains 2 mol of zinc ions and at least 1 mol of cobalt ion, whereas 1 mol of the truncated MAP lacking the putative zinc fingers contains only a trace amount of zinc ions but still contains one mole of cobalt ion. These results suggest that the two zinc ions observed in the native yeast MAP are located at the Cys/His rich region and the cobalt ion is located in the catalytic domain. The kcat and Km values of the purified truncated MAP are similar to those of the wild-type MAP when measured with peptide substrates in vitro and it appears to be as active as the wild-type MAP in vivo. However, the truncated MAP is significantly less effective in rescuing the slow growth phenotype of map mutant than the wild-type MAP. These findings suggest that the zinc fingers are essential for normal MAP function in vivo, even though the in vitro enzyme assays indicate that they are not involved in catalysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Sex differences in cell proliferation in the ventricular zone of young ring doves

Cell proliferation in the ventricular zone was studied in 3-month-old ring doves, using [3H]-thymidine as the marker for DNA synthesis and hence cell division. We found sex differences in the rate of cell proliferation on the plane of preoptic area in these immature doves whose gonads were just undergoing changes.

Hypopituitarism and chorioretinopathy in two siblings

Two male siblings with chorioretinopathy and pituitary dysfunction (CPD) were found to have empty sellas on CT scan. Extensive ophthalmological and endocrinological investigation revealed the absence of gonadotrophins in both brothers and growth hormone deficiency in one. ACTH, TSH, and posterior pituitary function were normal. Karyotyping in one brother revealed a 46XY complement. Ophthalmological evaluation of three other siblings and both parents revealed normal vision and no evidence of retinopathy. The brothers represent two additional examples of CPD syndrome, suggesting a genetic etiology for this syndrome complex. The empty sellas present add another facet to the central nervous system disorders found in CPD syndrome.

Comparison of dietary habits, physical activity and body size among Chinese in North America and China

BACKGROUND

Chinese in North America have higher rates of many chronic diseases than do Chinese in Asia. However, there is a lack of data among comparisons of the environmental and lifestyle factors for Chinese in China and Chinese residing in North America.

METHODS

We examined self-reported dietary nutrient intakes, physical activity patterns and body mass index of 2488 healthy Chinese men and women residing in North America (US and Canada) and in the People's Republic of China.

RESULTS

On average, Chinese in China consumed more calories (males 2904 kcal in China, versus 2201 kcal in North America; females 2317 Kcal in China, versus 1795 Kcal in North America and more carbohydrate, but less fat (males 72.2 g in China versus 84.5 g in North America, females 56.6 g in China versus 70.8 g in North America), protein, vitamin A, beta-carotene and vitamin C than did Chinese in North America. Per cent calories from fat was 35% for Chinese in North America and 22% for Chinese in China. In contrast, the per cent of calories from carbohydrates was 62-68% in China and 48% in North America. Chinese in China reported spending more time in vigorous activity, sleeping and walking but less hours in sitting than Chinese in North America. Chinese in China weighted less and were leaner than North American Chinese.

CONCLUSIONS

These differences in nutrient intakes, physical activity and body size of Chinese living on two different continents suggest possible explanations for observed differences in chronic disease rates in the two populations.

A comparative trial between diclofenac-gentamicin and betamethasone-neomycin drops in patients undergoing cataract extraction

Eighty patients were randomised in a single-masked parallel-group study to receive topically either the test drug, a diclofenac and gentamicin combination, or a betamethasone and neomycin combination after routine cataract extraction and intraocular lens implantation. Each group was assessed over a 6 week period for post-operative inflammation. The two drug combinations were equally effective in suppressing inflammation in the early post-operative stages and the diclofenac-gentamicin combination was slightly more effective in the later stages. The test drug was well tolerated and showed no adverse effects. We feel it is an effective and relatively safe drug which has a role as an anti-inflammatory agent after cataract extraction and has potential advantages in certain circumstances.

Interlocking Crawford triangles in frontalis suspension

In Crawford's pattern of frontalis suspension, two bands are passed, one nasally and the other temporally, forming two base-down triangles with their apexes attached at the brow incisions. Over time, opposing vector forces in the center of the eyelid can cause "cheese-wiring" of the bands with resultant shortening of the inferior bases of both triangles and loosening of the suspensory loops. We modified the standard pattern by interlocking the bands centrally in the lid. A mathematical model was developed that demonstrates neutralization of these opposing forces, resulting in a symmetrical and flexible redistribution of the lifting forces. In support of this mathematical model, a retrospective analysis of 42 consecutive cases using this technique revealed good aesthetic results in terms of lid height, contour, and symmetry, with no important complications from this modification.

Bilateral retinal haemorrhages following epidural injection

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Immunisation of macaques with SIV env recombinants: specificity of T cell and antibody responses and evaluation of protective efficacy

Macaques were immunised with lentil lectin purified recombinant SIVmac (BK28) derived gp160 (rgp160) with or without live vaccinia (vac)-env (BK28) priming, followed by a final boost with solid matrix antibody antigen (SMAA)-gp160 (J5) complexes and challenged with the SIVmac molecularly cloned virus J5M. Rgp160 and vac-env plus gp160 induced strong Ab responses against the homologous virus. Live vac-env did not enhance or prolong the antibody response, however, T cell responses were stronger. Analysis of the specificity of the immune response demonstrated that sequence variation within SIVmac viruses can affect antibody and T cell recognition. A single booster immunisation with the heterologous SIVmac J5 env recombinant protein was not sufficient to protect against the molecularly cloned virus J5M. These findings further illustrate the difficulty of generating protective immunity with immunogens based on single sequence recombinants.

Restriction of serum antibody reactivity to the V3 neutralizing domain of HIV gp120 with progression to AIDS

OBJECTIVE

To identify epitopes on HIV-1 gp120 that correlate with disease resistance and/or prognostic indication.

DESIGN

The identification of epitopes on HIV-1 gp120 was determined by testing the reactivity by immunoblotting of anti-HIV-positive human sera against partially cleaved Chinese hamster ovary (CHO) cell-derived recombinant gp120. Cleavage of recombinant gp120 occurs in the V3 loop region resulting in 70 and 50K cleavage bands if the protein is subjected to sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) under reducing conditions. Antibodies reactive with the 120 Mr band alone on immunoblotting indicate that binding is restricted to this cleavage site. Reactivity to either of the cleavage products is independent of gp120 cleavage and indicates that binding occurs in sites other than the V3 cleavage region.

METHODS

A panel of anti-HIV-positive human sera was tested for virus neutralizing activity and reactivity by immunoblotting against CHO cell-derived gp120.

RESULTS

All sera reacted with the uncleaved from of gp120 but reacted either weakly or did not react with its cleavage products. There was a statistically significant correlation between serum reactivity to cleavage products and clinical stage of disease [Centers for Disease Control (CDC) criteria]. Sera of asymptomatic individuals (CDC stage II/III) were more likely to recognize either one or both of the cleavage products compared with sera from patients presenting with symptoms of disease (CDC stage IV). Furthermore, sera reacting with either one or both of the cleavage products were more likely to have higher neutralizing antibody titres than those that were unreactive.

CONCLUSIONS

There is a restriction of serum antibody reactivity (when tested by immunoblotting) to the V3 loop with progression to disease. Raised neutralizing antibody titres may be dependent on regions outside the V3 cleavage site.

Protection against SIV infection in macaques by immunization with inactivated virus from the BK28 molecular clone, but not with BK28-derived recombinant env and gag proteins

Vaccination of cynomolgus macaques with beta-propiolactone inactivated SIVmacBK28 in Freund's adjuvant induced low but detectable levels of anti-SIV envelope (env) antibodies and T-cell responses and protected against challenge with the 32H isolate of SIVmac251 grown in C8166 cells. In contrast, purified recombinant SIV env and gag proteins derived from BK28 formulated in Syntex adjuvant generated consistent and long-lived cellular and humoral immune responses to SIV env, but failed to protect against infection with the 32H virus. Thus, protection against a heterogeneous challenge stock is possible by immunization with a molecularly-cloned virus, but not with recombinant proteins from the same molecular origin. High levels of anti-cell antibodies induced by the whole virus vaccine, but not by recombinant proteins, may have contributed to the protection observed.

Vaccine-induced CD4+ T cells against the simian immunodeficiency virus gag protein. Epitope specificity and relevance to protective immunity

We have examined the induction and epitope specificity of T cells for the simian immunodeficiency virus (SIV) gag p27 protein in macaques immunized with either a recombinant SIV gag protein or an inactivated SIV vaccine. CD4+ MHC class II-restricted T cell lines and clones derived from five immunized macaques recognized a total of seven peptides in three immunodominant regions of p27. Two T cell clones generated from one of the lines, recognized a single 20 amino acid peptide that overlapped with a region previously shown to include a CTL epitope from SIV-infected macaques. Although this epitope is in a conserved region of the gag protein of SIV, its recognition by a CD4+ T cell clone was abrogated by sequence variation in the equivalent HIV protein. The specificity of the T cell lines for synthetic peptides demonstrated considerable overlap between T cells generated by immunization with the recombinant gag protein and inactivated SIV. However, in contrast to the protective efficacy of the whole virus vaccine in the syntex adjuvant formulation, immunization with the p27 protein with alum failed to generate a protective immune response. Furthermore, despite the consistent gag-specific T cell responses induced by the recombinant protein, there was no evidence of an enhanced antibody response to envelope (env) after live SIV challenge.

Vaccine-induced CD4+ T cells against the simian immunodeficiency virus gag protein. Epitope specificity and relevance to protective immunity

We have examined the induction and epitope specificity of T cells for the simian immunodeficiency virus (SIV) gag p27 protein in macaques immunized with either a recombinant SIV gag protein or an inactivated SIV vaccine. CD4+ MHC class II-restricted T cell lines and clones derived from five immunized macaques recognized a total of seven peptides in three immunodominant regions of p27. Two T cell clones generated from one of the lines, recognized a single 20 amino acid peptide that overlapped with a region previously shown to include a CTL epitope from SIV-infected macaques. Although this epitope is in a conserved region of the gag protein of SIV, its recognition by a CD4+ T cell clone was abrogated by sequence variation in the equivalent HIV protein. The specificity of the T cell lines for synthetic peptides demonstrated considerable overlap between T cells generated by immunization with the recombinant gag protein and inactivated SIV. However, in contrast to the protective efficacy of the whole virus vaccine in the syntex adjuvant formulation, immunization with the p27 protein with alum failed to generate a protective immune response. Furthermore, despite the consistent gag-specific T cell responses induced by the recombinant protein, there was no evidence of an enhanced antibody response to envelope (env) after live SIV challenge.

Use of a fluorescent DNA analog for fluorometric detection of DNase activity

The enhancement of fluorescence of the DNA analog poly(d epsilon A) following nucleolytic degradation to mononucleotides was found to be a convenient signal for studying nuclease, especially exonuclease, activity. This measurement, which is simple to obtain and extremely sensitive, detects various kinds of DNases and can be applied to the detection of nucleases in the course of protein purification. The signal change can be observed continuously during the reaction and easily converted to the amount of liberated mononucleotide. The method is thus suitable for quantitative and kinetic studies of exonuclease activity.

Studies on the immunogenicity of Chinese hamster ovary cell-derived recombinant gp120 (HIV-1IIIB)

Recombinant DNA-derived gp120 (HIV-1IIIB) expressed in chinese hamster ovary cells elicited specific humoral and cell-mediated immune responses in a variety of mammals. Antisera from immunized rabbits, sheep and goats recognized virus-derived gp120 and its precursor (gp160). Neutralizing antibodies were also elicited, but only in a few animals, and this may be related to the protein's susceptibility to cleavage through the neutralizing domain. However, in rabbits the degree of cleavage of gp120 had little or no effect on its antigenicity or immunogenicity. All antisera had limited cross-reactivity to envelope glycoproteins from a panel of HIV-1 isolates suggesting that immunodominant antibody epitopes are in variable regions of the recombinant gp120. Antigen-specific T-cell responses were detected in immunized macaques and were found to be stronger and more prolonged when gp120 was administered in Freund's adjuvant rather than alum.

The production and purification of PCR-derived recombinant simian immunodeficiency virus p27 gag protein; its use in detecting serological and T-cell responses in macaques

The polymerase chain reaction (PCR) was used to amplify a region of the gag gene, encompassing the core protein p27, from genomic DNA of cells infected with SIVmac251 (32H isolate). The 767 base pair PCR product was cloned into the bacteriophage M13 and fully sequenced before sub-cloning into the expression vector pUC19. The 30 kilodalton (kDa) fusion protein of lacZ-p27 was expressed as a soluble protein in E. coli JM101 cells and purified to greater than 90% purity by affinity chromatography. The affinity purified product was used in serological and T-cell assays to assess immune function in cynomolgus macaques immunised or challenged with immunodeficiency virus derived material. This reagent and accompanying methods provide valuable assays for monitoring the efficacy of vaccines for SIV as a model for human AIDS.

Polyadenylated messenger RNA in paired helical filament-immunoreactive neurons in Alzheimer disease

An antibody raised against isolated paired helical filaments (PHF) was used to identify tangle-bearing (PHF+) neurons in autopsy brain tissue from six Alzheimer disease (AD) patients and six age-matched controls (AMC). A comparison of the levels of polyadenylated messenger RNA [poly(A)+ mRNA] in PHF+ and PHF- neurons of similar cross-sectional area in temporal and parietal lobe and cerebellum from four AD and four AMC brains was made by analysis of in situ hybridization of [3H] polyuridylate [poly(U)] to intracellular poly(A)+ mRNA. In PHF+ neurons, the level of poly(A)+ mRNA was approximately two-thirds that in similar-sized PHF- neurons in either AD or AMC. The level of poly(A)+ mRNA in PHF- neurons in regions of the brain that have more of the histopathologically defined effect in AD was similar to that in regions with less effects.

Brain interleukin 1 and S-100 immunoreactivity are elevated in Down syndrome and Alzheimer disease

Interleukin 1, an immune response-generated cytokine that stimulates astrocyte proliferation and reactivity (astrogliosis), was present in up to 30 times as many glial cells in tissue sections of brain from patients with Down syndrome and Alzheimer disease compared with age-matched control subjects. Most interleukin 1-immunoreactive glia in Down syndrome and Alzheimer disease were classified as microglia. The number of interleukin 1 immunoreactive neurons did not appear to differ in Down syndrome and Alzheimer disease compared with control brain. Numerous temporal lobe astrocytes in Alzheimer disease and postnatal Down syndrome were intensely interleukin 1-, S-100-, and glial fibrillary acidic protein-immunoreactive and had reactive structure. Interleukin 1 levels in Alzheimer disease temporal lobe homogenates were elevated, as were the levels of S-100 and glial fibrillary acidic protein, two proteins reportedly elevated in reactive astrocytes. These data suggest that increased expression of S-100 in Down syndrome, resulting from duplication of the gene on chromosome 21 that encodes the beta subunit of S-100, may be augmented by elevation of interleukin 1. As a corollary, the astrogliosis in Alzheimer disease may be promoted by elevation of interleukin 1.

Dose parameters of 125I and 192Ir seed sources

As mandated by an NCI brachytherapy contract, we measured dosimetric parameters for 192Ir seeds and two models of 125I seeds. Measurements were with LiF powder in a water-equivalent phantom. Data were corrected for background, sample mass, and finite detector volume. Selected parameters were also investigated through Monte Carlo calculations. Results are presented in terms of a dose parametrization that is described in detail, and are compared to published data. Our results agreed well with published data for relative quantities such as radial and angular dose dependence. Our measured value for the 192Ir dose factor was 4.55 cGy(H2O) cm2 mCi-1 h-1, also in good agreement with commonly used values. However, the measured dose factors for 125I seed models 6702 and 6711 were 1.18 and 1.06 cGy(H2O) cm2 mCi-1 h-1, values well below those in general use.

Auger electron contribution to bromodeoxyuridine cellular radiosensitization

Halogenated thymidine analogs become incorporated into the DNA of proliferating cells during S-phase and may be used clinically to radiosensitize tumors that are otherwise poorly responsive to radiation. Although radiosensitization has been studied for years, mechanisms of radiosensitization are poorly understood. One possible mechanism involves the release of short range, high-LET, Auger electrons following photoelectric absorption of an X ray by the K-shell of the incorporated halogen. Such absorption occurs only with X ray energies slightly greater than the K-shell binding energy. We report the results of an experiment designed to measure this effect, in which cultured monolayers of Chinese hamster V79 cells, with 32% replacement of thymidine by bromodeoxyuridine (BUdR), were exposed to monoenergetic X rays just below (13.450 KeV) or above (13.490 KeV) the K-edge (13.475 KeV) of bromine. Enhancement ratios calculated in five different ways were slightly increased (3-12%) above the K-edge compared to below. However, only a calculation using a linear-quadratic fit to the data and a surviving fraction of 0.01 demonstrated a statistically significant increased enhancement ratio (12%) above the K-edge. We conclude that Auger electrons produced following photoelectric absorption of X rays by the K-shell of bromine contribute minimally to observed BUdR cellular radiosensitization.

Fast abortive initiation of uvrA promoter in a supercoiled plasmid studied by stopped-flow techniques

In order to follow the fast kinetics of abortive initiation (lag time from 1 ms to 10 s), we have built a stopped-flow apparatus equipped for fluorescence detection. The small volume used for each assay (35 microliters), and the short dead time (approximately 0.5 ms) are the essential advantages of this apparatus. Supercoiling of DNA affects considerably the initiation of transcription from the uvrA promoter. It decreases the lag time due to the isomerisation process 3-fold. Nevertheless, it does not change significantly the product KBk2, which is indicative of promoter strength and shows that uvrA is an 'association-limited' promoter. The presence of the LexA repressor increases the lag time considerably. At least for small RNA polymerase concentrations this increase is stronger for supercoiled than for linearized DNA.

Non-A/non-B hepatitis in experimentally infected chimpanzees: cross-challenge and electron microscopic studies

Inoculation of eight chimpanzees with factor VIII, factor IX, or "H" strain plasma resulted in enzymatic and histopathologic evidence of non-A/non-B hepatitis in all eight animals. Challenge of two chimpanzees convalescent from factor VIII-induced disease with either factor IX or "H" strain plasma resulted in non-A/non-B hepatitis only in the animal inoculated with factor IX materials. Reciprocal cross-challenge of a chimpanzee convalescent from factor IX-induced disease with factor VIII also produced unequivocal enzymatic and histopathologic evidence of non-A/non-B hepatitis. Cross-challenge of a chimpanzee convalescent from "H" strain-induced non-A/non-B hepatitis with factor VII did not cause a second bout of non-A/non-B hepatitis. These findings suggest the factor VIII materials and "H" strain plasma used in these studies share a common etiologic agent (or agents), but that factor VIII and factor IX may contain two distinct agents. Electron microscopic (EM) examination of thin-sectioned, acute-phase liver biopsies from all but one of the chimpanzees receiving the primary inocula revealed the presence of abnormal hepatocyte cytoplasmic structures previously shown to be associated with non-A/non-B hepatitis. Crystalline structure containing 25 to 30 nm particles were visualized by EM in the cytoplasm of endothelial or Kupffer cells in acute-phase liver biopsies obtained from three chimpanzees inoculated with either factor VIII materials or "H" strain plasma.

Incidence of HBsAg, anti-HBs and subtypes ad and ay in a general hospital: correlation with clinical data and its significance as a public health problem

During a period of four months, 9,418 individuals, comprising new hospital admissions, new employees and blood donors, were tested for HbsAg and 1,212 for anti-HBs. A high incidence of positivity for both was found in the different groups under investigation. Subtyping was carried out on acutely ill patients and carriers. Sbtype ay was common in acutely ill patients and among addicts and subtype ad in nonhepatitis patients and healthy carriers. The significance of these findings and possible measures for prevention of spread of the infection are discussed.