Modulation of stress protein (hsp27 and hsp70) expression in CD4+ lymphocytic cells following acute infection with human immunodeficiency virus type-1

This study was designed to assess the impact of acute human immunodeficiency virus (HIV-1) infection on host intracellular expression of the heat shock family of stress proteins (hsps). Experimental conditions were established wherein CD4+ lymphocytic cell lines undergo a synchronous HIV-1 infection cycle. During the early phase of infection, HIV-1 mRNA expression was restricted to singly and multiply spliced subspecies, with no genomic viral RNA present until 30 hr following infection. In contrast, hsp27 and hsp70 mRNA transcription appeared as early as 3-8 hr following viral infection. No corresponding induction was observed in mock-infected cells. Notably, hsp27 and hsp70 mRNA transcripts were down-regulated by 24 hr, concomitant to the first appearance of full-length genomic HIV-1 mRNA. Hsp27 and hsp70 mRNA transcripts reemerged at end stages of the viral replicative cycle, coincident to virion release and CD4 cell death. Similarly, a transient induction of de novo hsp27 protein expression occurred between 12 and 24 hr. The generated hsp27 stress response was viral dose-related, suppressed by heat-inactivation of virus, and abrogated by neutralizing antibodies to HIV-1. Acute infection did not alter levels of hsp60, hsp70, and hsp90 protein synthesis. However, two-dimensional Western blot analysis did show the appearance of novel hsp70 homologues between 6 and 24 hr following infection. CEM.NKR, Jurkat, H9, and MT-2 cells showed similar patterns of viral-associated modulation of host hsp27 and hsp70 protein and RNA expression. Thus, host hsp27 and hsp70 stress pathways are selectively implicated in the HIV-1 viral life cycle.

Pain as a predictor of outcome in patients with operable pancreatic carcinoma

BACKGROUND

The purpose of our study was to evaluate the relationship between pain and resectability and survival in patients with operable pancreatic carcinoma.

METHODS

Pain, pain intensity, and pain location were prospectively assessed in newly diagnosed patients with operable adenocarcinoma of the pancreas. Patients were evaluated before their first operation at a large tertiary care cancer center. Pain factors were then correlated with outcomes of surgery, including resectability and survival.

RESULTS

Seventy-seven patients with operable pancreatic carcinoma were evaluated before operation. With the Memorial Pain Assessment Card and a demographic questionnaire, an analysis of analgesic use and pain prevalence and intensity were quantitated. Twenty-two (29%) of 77 patients reported no pain. Fifty-five had mild to severe pain. Moderately severe or greater pain (Memorial Pain Assessment Card Tursky scores of 5 or greater or visual analogue self-assessment pain intensity scores greater than 30) was found in 20 patients. Twenty-six (34%) patients had resectable disease. Of the 51 patients who did not have resections, 35 had metastatic disease. Locoregional unresectable disease without metastases was found in 16 patients. Resectability was correlated with the presence of pain (p = 0.04). The median survival for all patients was 6.7 months. Not surprisingly, patients undergoing resection had a significantly better median survival than did those whose disease was unresectable (5.5 versus 15.1 months). Pain before operation significantly predicted survival (median survival for those with pain, 5.7 months; for those without pain, 15 months; p = 0.003). Even among patients who underwent resection, the presence of pain was associated with a worse survival (21.9 months versus 9.2 months; p = 0.045). In a multivariate analysis the two significant variables were inability to undergo resection and presence of any pain.

CONCLUSIONS

The presence of pain in newly diagnosed patients with potentially operable pancreatic cancer is an ominous predictor of resectability and of survival. Even if the patient can undergo resection, the presence of preoperative pain is associated with a poor prognosis. Patients with operable pancreatic cancer who present with pain, even those whose evaluation shows a likelihood of resectability, are at high risk for recurrence with an impaired survival compared with those patients without pain.

Structure of bacteriophage T4 fibritin: a segmented coiled coil and the role of the C-terminal domain

BACKGROUND

Oligomeric coiled-coil motifs are found in numerous protein structures; among them is fibritin, a structural protein of bacteriophage T4, which belongs to a class of chaperones that catalyze a specific phage-assembly process. Fibritin promotes the assembly of the long tail fibers and their subsequent attachment to the tail baseplate; it is also a sensing device that controls the retraction of the long tail fibers in adverse environments and, thus, prevents infection. The structure of fibritin had been predicted from sequence and biochemical analyses to be mainly a triple-helical coiled coil. The determination of its structure at atomic resolution was expected to give insights into the assembly process and biological function of fibritin, and the properties of modified coiled-coil structures in general.

RESULTS

The three-dimensional structure of fibritin E, a deletion mutant of wild-type fibritin, was determined to 2.2 A resolution by X-ray crystallography. Three identical subunits of 119 amino acid residues form a trimeric parallel coiled-coil domain and a small globular C-terminal domain about a crystallographic threefold axis. The coiled-coil domain is divided into three segments that are separated by insertion loops. The C-terminal domain, which consists of 30 residues from each subunit, contains a beta-propeller-like structure with a hydrophobic interior.

CONCLUSIONS

The residues within the C-terminal domain make extensive hydrophobic and some polar intersubunit interactions. This is consistent with the C-terminal domain being important for the correct assembly of fibritin, as shown earlier by mutational studies. Tight interactions between the C-terminal residues of adjacent subunits counteract the latent instability that is suggested by the structural properties of the coiled-coil segments. Trimerization is likely to begin with the formation of the C-terminal domain which subsequently initiates the assembly of the coiled coil. The interplay between the stabilizing effect of the C-terminal domain and the labile coiled-coil domain may be essential for the fibritin function and for the correct functioning of many other alpha-fibrous proteins.

PAF antagonists as possible inhibitors of corneal epithelial defects and ulceration

The extracellular matrix (ECM) plays a crucial role in cell adhesion, differentiation and wound-healing. Its stability is tightly controlled by enzymes that regulate the metabolism of its components (e.g collagen, fibronectin, laminin). We have found that in the cornea, a potent lipid inflammatory mediator platelet-activating factor (PAF) activates the expression of two metalloproteinases (MMP-1 and MMP-9) as well as urokinase-plasminogen activator (uPA). uPA is of particular interest because, as a serine protease, it is at the top of the protease cascade. PAF may contribute to the destruction of the ECM and the formation of epithelial defects and corneal ulcers by activating uPA and then proteases. We also investigated how several PAF antagonists with different binding affinities can block the expression of the uPA gene. Our results suggest that PAF antagonists with affinities for intracellular binding sites and/or specific structures derived from triazolobenzodiazepine could be of therapeutic use to limit the breakdown of the ECM and the development of ulcer formation.

Effect of radix Salviae miltiorrhizae on extracellular adenosine and evaluation of its protective efficacy in ischemic reperfusion rat--microdialysis, HPLC and histopathologic studies

The effects of Radix Salviae Miltiorrhizae (RSM) on extracellular adenosine (Ade) and its metabolites, i.e. inosine, hypoxanthine and xanthine, were studied with microdialysis and HPLC techniques during cerebral ischemia-reperfusion induced by 4-vessel occlusion in rat brain. Histological examination of hippocampus was performed 6 h after reperfusion. ECF (extracellular fluid) adenosine and its metabolites were compared between the controls (n = 6) and RSM-treated rats (n = 6). Basal level of Ade and its metabolites release were not greatly affected by pretreatment with RSM, and no significant difference as compared with the sham-operated (n = 6). Ade and its metabolites were dramatically increased after ischemia, and decreased near basal-level and its metabolites remained high at the end of reperfusion. In the RSM-treated animals, the tendency of changes of Ade and its metabolites was just the same as in the controls, but the magnitudes of changes were significantly lower at some different time points. In sham-operated animals, no changes were observed at different time points both during ischemia (30 min.) and reperfusion (60 min.). Histopathological findings demonstrated that RSM pretreatment results in better histologic preservation of the pyramidal cells in the postischemic reperfusion CA1 sector both qualitatively and quantitatively. These results indicated that RSM protects against cerebral ischemia reperfusion injury.

Specific interactions and potential functions of human TAFII100

Human transcription initiation factor TFIID contains the TATA-binding protein (TBP) and several TBP-associated factors (TAFs). To investigate the structural organization and function of TFIID, we have cloned and expressed a DNA encoding the third largest human TFIID subunit, hTAFII100. Immunoprecipitation studies demonstrate that hTAFII100 is an integral subunit that is associated with all transcriptionally-competent forms of TFIID. They further suggest that at least part of the N-terminal region lies on the surface of TFIID, while a C-terminal region containing conserved WD-40 repeats appears inaccessible. Both in vivo and in vitro assays indicate that hTAFII100 interacts strongly with the histone H4-related hTAFII80 and the histone H3-related hTAFII31, as well as a stable complex comprised of both hTAFII80 and hTAFII31. Apparently weaker interactions of hTAFII100 with TBP, hTAFII250, hTAFII28, and hTAFII20, but not hTAFII55, also have been observed. These results suggest a role for hTAFII100 in stabilizing interactions of TAFs, especially the histone-like TAFs, in TFIID. In addition, functional studies show that anti-hTAFII100 antibodies selectively inhibit basal transcription from a TATA-less initiator-containing promoter, relative to a TATA-containing promoter, suggesting a possible core promoter-specific function for hTAFII100.

Randomized trial of breast self-examination in Shanghai: methodology and preliminary results

BACKGROUND

The efficacy of breast self-examination in helping to reduce mortality from breast cancer has not been rigorously demonstrated.

PURPOSE

To assess efficacy, a large, randomized trial was initiated in Shanghai, China.

METHODS

From October 1989 to October 1991, 267040 current and retired female employees associated with 520 factories in the Shanghai Textile Industry Bureau were randomly assigned on the basis of factory to either a self-examination instruction group (133375 women) or a control group (133665 women). The women were born within the period from 1925 through 1958. Women in the instruction group were given intensive training in breast self-examination, including the use of silicone breast models and personalized instruction, plus two subsequent reinforcement sessions and multiple reminders to practice the technique. Women in the control group were asked to attend training sessions on the prevention of low back pain. All women have been followed for the development of breast diseases and for death from breast cancer.

RESULTS

A high level of participation during the first 4-5 years of the trial was documented among women in the instruction group. Randomly sampled women in this group demonstrated greater proficiency in detecting lumps in breast models than did randomly sampled women in the control group. Approximately equal numbers of breast cancers were detected in the two groups (331 in the instruction group and 322 in the control group) through 1994, which is the last year for which case-finding efforts have been completed. The breast cancers detected in the instruction group were not diagnosed at an appreciably earlier stage or smaller size than those in the control group. More benign breast lesions were detected in the instruction group than in the control group (1457 versus 623, respectively), suggesting a higher index of suspicion for women who received training. Cumulative breast cancer mortality rates through 5 years from entry into the study were nearly equivalent for the two groups.

CONCLUSIONS

Breast self-examination has not led to a reduction in mortality from breast cancer in this study cohort in the first several years since the trial began. A shift toward the diagnosis of disease at a less advanced stage in women given instruction has also not been demonstrated. Longer follow-up of participants in this trial is required before final assessment can be made of the efficacy of breast self-examination.

IMPLICATIONS

At this time, there is insufficient evidence to recommend for or against the teaching of breast self-examination.

Endometrial thickness in tamoxifen-treated patients: correlation with clinical and pathologic findings

OBJECTIVE

This study was performed to evaluate sonographic measurements of endometrial thickness in postmenopausal breast cancer patients being treated with tamoxifen and to correlate endometrial thickness with pathology, symptoms, and duration of tamoxifen treatment.

MATERIALS AND METHODS

Pelvic sonograms and medical records of 91 postmenopausal breast cancer patients being treated with tamoxifen were retrospectively reviewed. Histologic results were available in 46 patients (51%). Endometrial thickness was measured in anteroposterior dimension and was considered normal when less than 8 mm. Endometrial thickness was then correlated with histopathologic findings, symptoms, and duration of tamoxifen treatment.

RESULTS

Forty-seven examinations (52%) showed endometrial thickness of less than 8 mm and 44 examinations (48%) showed endometrial thickness of 8 mm or more. Endometrial biopsy was performed in 10 women (21%) in whom the endometrial thickness was less than 8 mm, revealing seven normal endometria, one endometrial polyp, and two insufficient samples. Endometrial biopsy was performed in 36 women (82%) in whom endometrial thickness was 8 mm or more, revealing three cases with more than one diagnosis. In this group, diagnoses included 14 normal endometria, 12 endometrial polyps, four endocervical polyps, three hyperplasias, two endometrial cancers, one papillary syncytial metaplasia, one cystic change, one inflammatory debris, and one insufficient sample. Postmenopausal bleeding prompted 20 studies, 12 of which revealed endometrial thickness of 8 mm or more. We found no difference in endometrial thickness of patients who had bleeding versus those who had no bleeding. Endometrial thickness increased with the duration of tamoxifen treatment. Seventy-three women being treated with tamoxifen for less than 5 years had a median endometrial thickness of 5 mm, and 44% of biopsies yielded abnormal results. Eighteen women receiving tamoxifen 5 years or longer had a median endometrial thickness of 14 mm, and 58% of endometrial biopsies in this group were abnormal. The two endometrial cancers occurred in women who were treated with tamoxifen for 6 years. Correlation between duration of tamoxifen use and endometrial thickness was significant (p < .026).

CONCLUSION

The majority of women being treated with tamoxifen were asymptomatic, but 48% of sonograms revealed an endometrial thickness of 8 mm or more. Endometrial polyps, the most common abnormality, were diagnosed in 33% of biopsies performed for endometrial thickness of 8 mm or more. Endometrial thickness showed no correlation with symptoms, but we found a statistically significant correlation between increased endometrial thickness and duration of tamoxifen treatment that was longer than 5 years.

[Allergic bronchopulmonary aspergillosis successfully treated with itraconazole]

A 67-year-old man was admitted to our hospital because of coughing, a low-grade fever, and abnormal shadows on a chest X-ray film. He had had asthma as a child, but had no asthmatic symptoms on admission. A CT scan showed collapse of the right middle lobe and mucoid impactions in the lingula. Bronchoscopy revealed thick mucus obstructing the right middle-lobe bronchus and the left upper-lobe bronchus. The eosinophil count and the IgE level were abnormally high. Aspergillus fumigatus was detected in his sputum. Tests for immediate skin reaction and precipitating antibody to aspergillus antigen were positive. After treatment with itraconazole he became asymptomatic. Radiographic abnormalities had resolved by 1 month after the start of treatment; a high resolution CT scan obtained after clinical improvement revealed central bronchiectasis. In this patient with allergic bronchopulmonary aspergillosis, a course of itraconazole alone was followed by satisfactory improvement.

Acylation-stimulating protein (ASP) regulates glucose transport in the rat L6 muscle cell line

Acylation-stimulating protein (ASP), a human plasma protein, is a potent stimulator of triglyceride synthesis and glucose transport in both human adipocytes and fibroblasts. The purpose of the present in vitro study was to examine the effect of ASP on glucose transport in muscle cells. ASP stimulated 2-deoxy-glucose transport (2-DG) in differentiated rat L6 myotubes in a time (30 min to 24 h) and concentration dependent manner (97% increase). The magnitude of the ASP effect on glucose transport was comparable to the time- and concentration-dependent effects seen with insulin (125% increase), but was additive to insulin, pointing to involvement of differential signalling pathways. ASP stimulation was dependent on cell differentiation in that glucose transport increased by only 12% in myoblasts, comparable to the effect of insulin in myoblasts (15% increase) demonstrating selective responsiveness of the differentiated myotubes to ASP and insulin. The mechanism for the ASP induced increase in glucose transport was also examined. ASP increased the Vmax for 2-DG transport by 183% (4.02 vs. 1.42 nmol/mg cell protein/30 s; ASP vs. Control, respectively). This could be explained by an increased translocation of glucose transporters (GLUT 1, GLUT 4 and GLUT 3) to the plasma membrane surface as demonstrated by Western analysis (+43% P < 0.05, +30% P < 0.05, and +49% P < 0.05, respectively). The effects of ASP were equal to those of insulin (+47%, +26% and +53% for GLUT 1, GLUT 4 and GLUT 3, respectively) and in all cases were paralleled by comparable glucose transport increases under the same incubation conditions. After long-term stimulation (24 h), Western analysis indicated that ASP had a permissive effect on insulin stimulated increases in total GLUT3 and GLUT4 cellular transporter content. These results suggest that muscle is also responsive to ASP and that ASP may play a role in glucose metabolism in both muscle and adipose tissue.

[Dynamic study on blood lead levels of pregnant women and infants in a district of Beijing]

Under strict quality control, the authors investigated the levels of PbB among 270 women from early pregnancy to delivery and their infants. The mean PbB levels of the first three months of pregnancy and delivery is 45.0 microg/L and 64.8 microg/L respectively. Analysis shows an increase of mean PbB level in the period of gestation, and a significant increase in the last three months. The mean PbB level of umbilical cord is 51.9 microg/L (10.4% umbilical cord PbB > 100 microg/L). The mean PbB level of infants increases with the months, it increases significantly after six months. Regression analysis confirmed the positive correlation between the PbB levels of first three and second three months of gestation, the PbB of delivery and umbilical cord, the PbB of umbilical coral and infants. The correlation coefficient of the PbB level of delivery and umbilical cord, the PbB level of infants at six months and at twelve months is 0.80 and 0.47 respectively.

Neurogenesis in neonatal rat brain is regulated by peripheral injection of basic fibroblast growth factor (bFGF)

Many major diseases of human brain involve deficiencies of select neuronal populations. As one approach to repair, we examined regulation of neurogenesis directly in vivo, employing postnatal day 1 (P1) cerebellar cortex, which is composed primarily of granule neurons and dividing precursors. We focused on basic fibroblast growth factor (bFGF), which stimulates precursor mitosis in culture and which is highly expressed in cerebellum during neurogenesis. Subcutaneous injection of bFGF increased [3H]thymidine ([3H]dT) incorporation, a marker for DNA synthesis, by 50% in whole cerebellar homogenates, suggesting that peripherally administered factor altered ongoing neural proliferation. Further, assay of isolated granule precursors revealed a 4-fold increase in [3H]dT incorporation following in vivo bFGF treatment, indicating that granule neuroblasts were the major bFGF-responsive population. Morphologic analysis indicated that twice as many granule precursors were in S-phase of the mitotic cycle after peripheral bFGF. To determine whether other neurogenetic populations respond to peripheral bFGF, we examined additional brain regions in vivo. bFGF stimulated DNA synthesis by 68% in hippocampus, and by > 250% in pontine subventricular zone (SVZ). In contrast, incorporation was not altered in basal pons or cerebral cortex, regions in which neurogenesis has already ceased. To define potential direct actions of peripherally administered factor, 125I-bFGF was used to study distribution. Intact 18 kDa 125I-bFGF was recovered from brain following peripheral injection, suggesting that the factor acted directly to stimulate mitosis in dividing neuroblasts. The stimulation of neuronal proliferation by exogenous bFGF suggests that the factor normally regulates neurogenesis, and provides new therapeutic approaches to promote functional recovery from nervous system diseases.

Inhibitory effect of 764-3 on Ca2+ uptake in rat brain synaptosomes

In an attempt to examine the effect of 764-3, a purified component extracted from Radix Salviae Miltiorrhizae (RSM), on calcium channel, Ca2+ uptake in rat brain synaptosome stimulated by high-K+ and Glutamate (Glu) was investigated by using radioisotope labeled 45CaCl2. It was found that 764-3 could decrease the uptake of Ca2+ induced by high-K+ (60 mM) and 0.1 mM glutamate in a concentration-dependent manner. The maximum inhibiting rates were 45.22 +/- 4.88% and 37.58 +/- 4.52%, respectively. The results indicated that neuroprotective effect of RSM on cerebral ischemic injury may be related to its blocking effects on calcium channel.

Thiamine status in patients receiving long-term home parenteral nutrition

OBJECTIVES

Clinical thiamine deficiency can occur in patients receiving total parenteral nutrition (TPN) without thiamine supplementation. Because considerable breakdown of thiamine may occur in the presence of bisulfite-containing amino acid solutions, subclinical thiamine deficiency may develop with the use of these solutions, even with appropriate thiamine supplementation. The current American Medical Association-Food and Drug Administration approved injectable multivitamin formula contains 3 mg of thiamine. This study was undertaken to determine whether this quantity of thiamine is sufficient to avoid clinical thiamine deficiency in long-term home TPN patients with negligible oral thiamine absorption and in the presence of bisulfite-containing amino acid solutions.

METHODS

Twenty-four long-term home TPN patients with oral caloric intakes below the norm were evaluated. Seventeen patients suffered from short bowel syndrome or radiation enteritis, and another three had draining gastrostomies that precluded all intestinal absorption. The duration of TPN therapy ranged between 1 and 164 months. Thiamine status was assessed by assaying thiamine pyrophosphate, transketolase activity, and blood thiamine levels.

RESULTS

All thiamine pyrophosphate and erythrocyte transketolase activity levels were within the normal range.

CONCLUSIONS

This study demonstrates that the currently recommended 3 mg of thiamine hydrochloride added to TPN solutions is adequate to maintain normal thiamine status. This should prevent the development of thiamine deficiency even in patients with compromised intestinal thiamine absorption, and in the presence of bisulfite-containing amino acid solutions.

Effect of radix Salviae miltiorrhizae on nitric oxide in cerebral ischemic-reperfusion injury

It has been postulated that nitric oxide (NO) is produced in significant amount on reperfusion of ischemic brain and could cause brain edema and cell death. This study was undertaken in an attempt to determine whether Radix Salviae Miltiorrhizae (RSM) could reduce cerebral NO contents in 4-vessel occlusion rat model after 30 min of global ischemia and 15 min of reperfusion. There was a significant increase in cerebral NO level in untreated animals as compared with sham-operated ones. By pretreatment with RSM the cerebral NO concentration was reduced to normal level. The possibilities of neuroprotective role of RSM in cerebral ischemic-reperfusion injury were discussed.

Platelet-activating factor enhances urokinase-type plasminogen activator gene expression in corneal epithelium

PURPOSE

To determine whether platelet-activating factor (PAF), a lipid mediator that is accumulated in the cornea after alkali burn, induces the gene expression of urokinase-type plasminogen activator (uPA) in the corneal epithelium. Possible signaling mechanisms of uPA gene induction by PAF also were examined.

METHODS

Rabbit corneas were cultured with or without PAF. One hour before stimulation, PAF antagonists or other modulators were added to PAF. In some experiments, the corneas were permeabilized to introduce guanosine triphosphate analogs into the corneal epithelial cells. Corneal epithelia were then harvested for Northern blot analysis, nuclear runoff transcription assay, and zymography.

RESULTS

Platelet-activating factor induced uPA mRNA expression in the corneal epithelium. New protein synthesis was not required for the induction of uPA mRNA. The induction was at the level of transcription as shown by nuclear runoff assays. Additionally, both actinomycin D and alpha-amanitin inhibited the increase in uPA mRNA by PAF. The message was translated into protein, which was secreted into the conditioned medium. An antagonist with high affinity for intracellular PAF binding sites (BN 50730) inhibited uPA gene expression and cellular secretion of the protein. The effect of PAF was not mediated by G proteins and was independent of protein kinase C- and cyclic adenosine monophosphate-dependent signal transduction pathways. Okadaic acid increased the expression of uPA and, at longer times, augmented the effect of PAF, suggesting that a signaling pathway that requires phosphorylation is involved in activated uPA mRNA synthesis.

CONCLUSIONS

After corneal injury and inflammation, PAF may be an important initiator of the proteolytic cascade, leading to epithelial defects and corneal ulceration. Antagonists of PAF could be useful in the prevention of these diseases.

Is there an error correcting code in the base sequence in DNA?

Modern methods of encoding information into digital form include error check digits that are functions of the other information digits. When digital information is transmitted, the values of the error check digits can be computed from the information digits to determine whether the information has been received accurately. These error correcting codes make it possible to detect and correct common errors in transmission. The sequence of bases in DNA is also a digital code consisting of four symbols: A, C, G, and T. Does DNA also contain an error correcting code? Such a code would allow repair enzymes to protect the fidelity of nonreplicating DNA and increase the accuracy of replication. If a linear block error correcting code is present in DNA then some bases would be a linear function of the other bases in each set of bases. We developed an efficient procedure to determine whether such an error correcting code is present in the base sequence. We illustrate the use of this procedure by using it to analyze the lac operon and the gene for cytochrome c. These genes do not appear to contain such a simple error correcting code.

Characterization of a vitellogenin receptor in white perch (Morone americana)

Receptors for white perch vitellogenin (wVTG) were characterized using wVTG, labeled in vivo with [3H]leucine or in vitro with 125I, and semipurified ovarian membranes. Specific binding of wVTG to the membranes was temperature-dependent, proportional to the amount of membrane, and saturable. Scatchard analyses revealed a single class of binding sites of low maximum binding capacity (MBC; approximately 35 pmol VTG/mg membrane protein) and high affinity (Kd approximately 400 nM), consistent with wVTG levels (540-2700 nM) circulating in maturing females. Ligand blotting revealed a receptor protein of M(r) approximately 157000 and a smaller protein, possibly its degradation product. Striped bass vitellogenin, chicken egg yolk very low density lipoprotein, and suramin displaced wVTG from its receptor, but BSA did not. No change in Kd was noted over the course of vitellogenesis in maturing perch, and MBC increased only slightly very late in the gametogenic cycle. The wVTG bound specifically to membranes prepared from liver, muscle, and mesenteric fat, but not to erythrocyte membranes. The Kd for ovary (394 nM) and liver (345 nM) were similar, but the Kd for muscle (1440 nM) was much higher.

Radix Salviae miltiorrhizae treatment results in decreased lipid peroxidation in reperfusion injury

In our pervious investigations we have found that Radix Salviae Miltiorrhizae (RSM) can reduce neurological deficits and ameliorate cellular damages, and its protective actions are associated with its effects on cerebral edema, monoamines, neuropeptides, neurotransmitter aminoacids, thromboxane A2, peroxidation and down-regulation of c-fos gene expression in ischemic animals. The purpose of present study was to investigate the protective effect of RSM against lipid peroxidation in 4-vessel occlusion and reperfusion rat model. We found that in RSM-treated rats the cerebral SOD activity is significantly increased, while the cerebral MDA level is significantly decreased when compared with untreated animals. The results suggested that RSM can reduce the lipid peroxidation and afford cerebroprotection against reperfusion injury.

Preliminary crystallographic studies of bacteriophage T4 fibritin confirm a trimeric coiled-coil structure

Fibritin, a 52-kDa product of gene wac of bacteriophage T4, forms fibrous "whiskers" that connect to the phage tail and facilitate the later stages of phage assembly. Preliminary experiments suggest that fibritin is a trimer, and its predominant central part has a parallel alpha-helical coiled-coil structure. To investigate the oligomerization and function of fibritin, we have designed and studied two related deletion mutants, denoted M and E, that consist of its last 75 and 120 amino acids, respectively. Both proteins contain part of the coiled-coil region and the 29 amino acid carboxy-terminal domain essential for the trimerization of fibritin. The proteins are expressed as a soluble product in an Escherichia coli system. We have obtained crystals of fibritins M and E. Complete native X-ray diffraction data sets have been collected to 1.85 and 2.7 A resolution, respectively. The crystals have space group P3 with a=44.3 A, c=91.3 A (fibritin M) and R32 with a=41.2 A, b=358.7 A (fibritin E) in the hexagonal setting. Symmetry and packing considerations show that fibritin is a triple coiled coil.

[Some aspects on surgical treatment of infratemporal fossa malignancies]

Thirteen patients with infratemporal fossa malignancies treated in the Sichuan Cancer Hospital from 1988 to 1993 are reported. All cases were treated surgically combined with pre-operative and post-operative radiotherapy with or without chemotherapy. The survival rate of the patients with survival period beyond 2 years was 53.8%. The survival was associated with the extent of dissection (P < 0.01). The operation value, surgical approaches, resection range, bone boundary of surgery, stylohamular line and repair are analysed and discussed.

Molecular cloning and functional expression of human deoxyhypusine synthase cDNA based on expressed sequence tag information

Deoxyhypusine synthase is an NAD(+)-dependent enzyme that catalyses the formation of a deoxyhypusine residue on the eukaryotic initiation factor 5A (eIF-5A) precursor by transferring an aminobutyl moiety from spermidine to the epsilon-amino group of a unique lysine residue. We have recently cloned and characterized the Neurospora crassa deoxyhypusine synthase cDNA using a reverse genetics approach. A GenBank search showed that a stretch of the deduced amino acid sequence (96 amino acids) of Neurospora deoxyhypusine synthase matches a short human expressed sequence tag (EST), Z25337, with greater than 70% amino acid identity. Gene-specific primers based on this EST were used together with universal primers to obtain 1219 bp and 1078 bp cDNAs from a human cDNA library. The 1219 bp and 1078 bp sequences, each containing an open reading frame, encode polypeptides of respectively 368 and 321 amino acids. The short sequence is identical to the long one except that it is missing a stretch of 47 amino acids spanning residues 261-307. The 368-amino-acid sequence of human deoxyhypusine synthase shares a high degree of identity ( > 50%) and similarity ( > 60%) with that of the Neurospora and yeast deoxyhypusine synthases. After cloning into an expression vector, the 368-amino-acid recombinant protein exhibits high deoxyhypusine synthase activity. In contrast, the 321-amino-acid recombinant protein shows no detectable activity.

Phase I study of continuous-infusion recombinant macrophage colony-stimulating factor in patients with metastatic melanoma

Macrophage colony-stimulating factor (M-CSF) is a lineage-specific, homodimeric growth factor that supports the proliferation and maturation of bone marrow progenitors and the survival and function of mononuclear/macrophage cells. In vitro studies have demonstrated antitumor activity of macrophage colony-stimulating factor-treated monocytes against melanoma target cells. A Phase I study was conducted by administering the glycosylated form of the protein to patients with metastatic melanoma as two 7-day continuous i.v. infusions separated by a 2-week rest. Cohorts of three patients per dose level received escalating doses of 10-160 microgram/kg/day. Safety, clinical, and biological effects were evaluated. The infusions were well tolerated with occasional maximum grade 2 nonhematological toxicity. Rapidly reversible thrombocytopenia was the major hematological adverse effect. Its etiology may in part be explained by proliferation and activation of monocyte/macrophage cells in bone marrow samples. Evidence for a biological effect on tumors was suggested by the delayed, complete disappearance of multiple lesions in one patient and a decrease in the size of one marker lesion in a second patient with a mixed response. Fasting serum cholesterol levels decreased during the infusions and may represent an additional therapeutic application for this growth factor.

Nitric oxide inhibits the initiation of cAMP pulsing in D. discoideum without altering receptor-activated adenylate cyclase

We have previously demonstrated that nitric oxide (NO)-releasing compounds inhibit the differentiation and aggregation of D. discoideum cells (Tao et al., FEBS Lett. 314:49, 1992). In the present study, we demonstrate that treatment of intact cells with NO-releasing compounds inhibits their production of cAMP. This occurred even though the developmental expression of the known components necessary for proper cAMP signalling was unaffected. The inhibitory effects of NO-releasing compounds on cell aggregation were reversed by stimulating cells with pulses of cAMP. In response to an applied cAMP pulse, NO-treated cells displayed a normal signal relay response, indicating that receptor-activated adenylate cyclase activity was not inhibited by NO. This also argues that the processes of desensitization/resensitization occur normally in NO-treated cells. The data indicate that the developmental expression of the components of the chemotactic signalling occurs independently of cAMP production and that the activity of the adenylate cyclase may be regulated by cAMP/ cAMP-receptor independent pathway. These findings indicate both a new mechanism for the regulation of adenylate cyclase in D. discoideum and a novel means by which NO can function to alter cellular processes.

Immunoglobulin and complement complexes in blood following infection with human immunodeficiency virus type 1

Freely soluble and complexed plasma immunoglobulin A (IgA), IgG, IgM, C1q, C3, and factor B in 36 human immunodeficiency virus type I (HIV-1)-seronegative controls, 69 asymptomatic HIV+ subjects, and 117 individuals with symptomatic HIV-associated disease were characterized. Levels of free and complexed IgG and IgA, and to a lesser extent free C1q and complexed IgM, increased with HIV-1 infection. In stark contrast, both HIV+ groups showed three- to sixfold declines in complexed C3, C1q, and factor B levels. The asymptomatic HIV+ population showed declines in levels of C3-bound IgA, IgG2, and IgG4 complexes. The asymptomatic group showed reductions in C3-complexed IgM, IgA, IgG2, and IgG4 levels. HIV infection is associated with complement-deficient immune complexes.