Anthropogenic climate change has altered primary productivity in Lake Superior

Anthropogenic climate change has the potential to alter many facets of Earth's freshwater resources, especially lacustrine ecosystems. The effects of anthropogenic changes in Lake Superior, which is Earth's largest freshwater lake by area, are not well documented (spatially or temporally) and predicted future states in response to climate change vary. Here we show that Lake Superior experienced a slow, steady increase in production throughout the Holocene using (paleo)productivity proxies in lacustrine sediments to reconstruct past changes in primary production. Furthermore, data from the last century indicate a rapid increase in primary production, which we attribute to increasing surface water temperatures and longer seasonal stratification related to longer ice-free periods in Lake Superior due to anthropogenic climate warming. These observations demonstrate that anthropogenic effects have become a prominent influence on one of Earth's largest, most pristine lacustrine ecosystems.

The impacts of climate change on the Great Lakes' ecosystems compared to historical records are unclear. Here, using paleolimnological evidence, the authors show that Lake Superior experienced a slow increase in productivity throughout the Holocene, but that this rate has increased in the last century.

A progressively wetter climate in southern East Africa over the past 1.3 million years

African climate is generally considered to have evolved towards progressively drier conditions over the past few million years, with increased variability as glacial-interglacial change intensified worldwide. Palaeoclimate records derived mainly from northern Africa exhibit a 100,000-year (eccentricity) cycle overprinted on a pronounced 20,000-year (precession) beat, driven by orbital forcing of summer insolation, global ice volume and long-lived atmospheric greenhouse gases. Here we present a 1.3-million-year-long climate history from the Lake Malawi basin (10°-14° S in eastern Africa), which displays strong 100,000-year (eccentricity) cycles of temperature and rainfall following the Mid-Pleistocene Transition around 900,000 years ago. Interglacial periods were relatively warm and moist, while ice ages were cool and dry. The Malawi record shows limited evidence for precessional variability, which we attribute to the opposing effects of austral summer insolation and the temporal/spatial pattern of sea surface temperature in the Indian Ocean. The temperature history of the Malawi basin, at least for the past 500,000 years, strongly resembles past changes in atmospheric carbon dioxide and terrigenous dust flux in the tropical Pacific Ocean, but not in global ice volume. Climate in this sector of eastern Africa (unlike northern Africa) evolved from a predominantly arid environment with high-frequency variability to generally wetter conditions with more prolonged wet and dry intervals.

Visual Data Analysis as an Integral Part of Environmental Management

The U.S. Department of Energy's (DOE) Office of Environmental Management (DOE/EM) currently supports an effort to understand and predict the fate of nuclear contaminants and their transport in natural and engineered systems. Geologists, hydrologists, physicists and computer scientists are working together to create models of existing nuclear waste sites, to simulate their behavior and to extrapolate it into the future. We use visualization as an integral part in each step of this process. In the first step, visualization is used to verify model setup and to estimate critical parameters. High-performance computing simulations of contaminant transport produces massive amounts of data, which is then analyzed using visualization software specifically designed for parallel processing of large amounts of structured and unstructured data. Finally, simulation results are validated by comparing simulation results to measured current and historical field data. We describe in this article how visual analysis is used as an integral part of the decision-making process in the planning of ongoing and future treatment options for the contaminated nuclear waste sites. Lessons learned from visually analyzing our large-scale simulation runs will also have an impact on deciding on treatment measures for other contaminated sites.

Plaque Development and Induction of Interferon Synthesis by RMC Poliovirus

Johnson, Terry C. (University of Minnesota, Minneapolis), and Leroy C. McLaren. Plaque development and induction of interferon synthesis by RMC poliovirus. J. Bacteriol. 90:565-570. 1965.-Plaque development by RMC poliovirus on human amnion cell monolayers was investigated with regard to autointerference and to the effect of acid-agar overlay on plaquing efficiency. The virus was inhibited by acid-agar overlay, thereby exhibiting the d(-) marker typical of attenuated poliovirus strains. In addition, a lack of RMC poliovirus plaque development on HeLa cell monolayers was shown to be the result of an agar inhibitor which could be removed by NaCl extraction. By use of a simplified plaque reduction assay, it was shown that interferon production was responsible for the autointerference phenomenon. Interferon synthesis did not correlate with the ages in vitro of human amnion cell cultures. Fibroblasts originating from the chorionic membrane produced negligible amounts of the inhibitor. Interferon synthesis by human amnion cells infected with RMC poliovirus was inhibited by actinomycin D. The addition of guanidine hydrochloride to infected cultures immediately after RMC poliovirus adsorption markedly inhibited interferon synthesis, although after 2 hr (postadsorption) guanidine had no effect on interferon production.

The rate of treatment of chronic hepatitis C in patients co-infected with HIV in an urban medical centre

Hepatitis C virus (HCV) and human immunodeficiency virus (HIV) co-infection is common. HIV co-infection results in a higher rate of histologic progression and shorter interval to HCV-related cirrhosis. Successful treatment of HCV with interferon-based therapy reduces the morbidity and mortality of patients. Significant factors may limit the availability of treatment in co-infected patients. The rate of treatment of HCV and limiting factors to treatment in a co-infected population in an urban setting were determined. A retrospective review of co-infected patients was conducted at our liver and gastrointestinal (GI) clinics for treatment of HCV from July 2001 to June 2002. Treatment of HCV and reasons for nontreatment were recorded. A total of 104 HCV/HIV co-infected patients were identified. Seventy-two per cent were males. Mean age was 47.2 years (32-72). Seventy-four of the 82 (90%) with identifiable risk factors for HCV infection had a history of intravenous drug use (IVDU). Twenty per cent (21/104) of the total underwent a liver biopsy. Sixty-seven per cent who had a liver biopsy were treated. Overall, sixteen patients were treated. Eighty-eight (85%) patients were not treated for the following reasons: 13 refused treatment, and 75 were ineligible. Of the ineligible patients, 40% were noncompliant with visits, 15% were active substance abusers, 13% had decompensated cirrhosis, 8% had significant active psychiatric conditions and 24% had significant co-morbid disease. A majority of patients co-infected with HCV/HIV had a IVDU history. Most co-infected patients were not eligible for HCV treatment. A majority of noncandidates had potentially modifiable psychosocial factors leading to nontreatment.

Spinal manipulation for primary and secondary dysmenorrhoea

BACKGROUND

Dysmenorrhoea refers to the occurrence of painful menstrual cramps of uterine origin and is a common gynaecological condition. One possible treatment is spinal manipulation therapy. One hypothesis is that mechanical dysfunction in certain vertebrae causes decreased spinal mobility. This could affect the sympathetic nerve supply to the blood vessels supplying the pelvic viscera, leading to dysmenorrhoea as a result of vasoconstriction. Manipulation of these vertebrae increases spinal mobility and may improve pelvic blood supply. Another hypothesis is that dysmenorrhoea is referred pain arising from musculoskeletal structures that share the same pelvic nerve pathways. The character of pain from musculoskeletal dysfunction can be very similar to gynaecological pain and can present as cyclic pain as it can also be altered by hormonal influences associated with menstruation.

OBJECTIVES

To determine the safety and efficacy of spinal manipulative interventions for the treatment of primary or secondary dysmenorrhoea when compared to each other, placebo, no treatment, or other medical treatment.

SEARCH STRATEGY

We searched the Cochrane Menstrual Disorders and Subfertility Group trials register (searched 18 March 2004), CENTRAL (The Cochrane Library Issue 1, 2004), MEDLINE (1966 to March 2004), EMBASE (1980 to March 2004), CINAHL (1982 to March 2004), AMED (1985 to March 2004), Biological Abstracts (1969 to Dec 2003), PsycINFO (1872 to March 2004) and SPORTDiscus (1830 to March 2004). The Cochrane Complementary Medicine Field's Register of controlled trials (CISCOM) was also searched. Attempts were also made to identify trials from the metaRegister of Controlled Trials and the citation lists of review articles and included trials. In most cases, the first or corresponding author of each included trial was contacted for additional information.

SELECTION CRITERIA

Any randomised controlled trials (RCTs) including spinal manipulative interventions (e.g. chiropractic, osteopathy or manipulative physiotherapy) vs each other, placebo, no treatment, or other medical treatment were considered. Exclusion criteria were: mild or infrequent dysmenorrhoea or dysmenorrhoea from an IUD.

DATA COLLECTION AND ANALYSIS

Four trials of high velocity, low amplitude manipulation (HVLA), and one of the Toftness manipulation technique were included. Quality assessment and data extraction were performed independently by two reviewers. Meta analysis was performed using odds ratios for dichotomous outcomes and weighted mean differences for continuous outcomes. Data unsuitable for meta-analysis were reported as descriptive data and were also included for discussion. The outcome measures were pain relief or pain intensity (dichotomous, visual analogue scales, descriptive) and adverse effects.

MAIN RESULTS

Results from the four trials of high velocity, low amplitude manipulation suggest that the technique was no more effective than sham manipulation for the treatment of dysmenorrhoea, although it was possibly more effective than no treatment. Three of the smaller trials indicated a difference in favour of HVLA, however the one trial with an adequate sample size found no difference between HVLA and sham treatment. There was no difference in adverse effects experienced by participants in the HVLA or sham treatment. The Toftness technique was shown to be more effective than sham treatment by one small trial, but no strong conclusions could be made due to the small size of the trial and other methodological considerations.

REVIEWERS' CONCLUSIONS

Overall there is no evidence to suggest that spinal manipulation is effective in the treatment of primary and secondary dysmenorrhoea. There is no greater risk of adverse effects with spinal manipulation than there is with sham manipulation.

Physical fitness and self-reported physical exercise among college men and women in 1987 and 1997

The study examined the relations of self-reported physical activity levels and physical fitness scores for two samples of college students assessed in 1987 (n = 261) and in 1997 (n = 243). Significantly greater exercise was reported by the 1997 women than the 1987 women; amount of exercise reported by men did not differ. For both samples, greater exercise was associated with increased fitness for women and men as assessed by the Hall 1986 Physical Fitness Test Profile, comprised of measures on body fat composition; grip strength; muscle endurance, flexibility, resting heart rate; systolic and diastolic blood pressures; and aerobic power. For the 1987 sample men were more fit than women. For the 1997 sample, women were more fit than men. The 1997 women were more fit than the 1987 women; there was no difference on overall fitness measures of the two samples of men.

The role of a cell surface inhibitor in early signal transduction associated with the regulation of cell division and differentiation

Serum stimulation of quiescent human fibroblast cultures resulted in a hyperphosphorylation of the nuclear retinoblastoma gene susceptibility product (RB). However, serum stimulation in the presence of 9 x 10(-8) M of a purified bovine sialoglycopeptide (SGP) cell surface inhibitor abrogated the hyperphosphorylation of the RB protein and the subsequent progression of cells through the mitotic cycle. The experimental results suggest that the SGP mediated its cell cycle arrest at a site in the cell cycle that was at the time of RB phosphorylation or somewhat upstream of the modification of this regulatory protein of cell division. Both cells serum-deprived and serum stimulated in the presence of the SGP displayed only a hypophosphorylated RB protein, consistent with the SGP-mediated cell cycle arrest point being near the G1/S interface.

Effects of stress induced by a simulated shooting on recall by police and citizen witnesses

Two experiments address the accuracy of citizen and police witnesses in recalling stressful events. Participants saw 2 training scenarios. Experiment 1 evaluated the effects of active engagement and the presence of a simulated shooting on police officers' memory for details. Police officers recalled significantly fewer details from the scenario in which a shooting occurred. Active engagement did not influence recall. Experiment 2 compared the memory performance of police and citizen witnesses. Manipulation checks were added to assess the arousal produced by a shooting, and control procedures were added to evaluate the memorability of specific scenarios. Police and citizen witnesses did not differ reliably in accuracy. The perpetrator was remembered less well than the weapon when a simulated shooting occurred, and one scenario was significantly more difficult to remember than the other. The need to replicate eyewitness research with a variety of materials is discussed.

Spinal manipulation for primary and secondary dysmenorrhoea

BACKGROUND

Dysmenorrhoea refers to the occurrence of painful menstrual cramps of uterine origin and is a common gynaecological condition. The efficacy of medical treatments such as nonsteroidal anti-inflammatories (NSAIDs) or oral contraceptive pills (OCPs) is considerable, however the failure rate can still be as high as 20-25% and there are also a number of associated adverse effects. Many women are thus seeking alternatives to conventional medicine. One popular treatment modality is spinal manipulation therapy. There are several rationales for the use of musculoskeletal manipulation to treat dysmenorrhoea. The parasympathetic and sympathetic pelvic nerve pathways are closely associated with the spinal vertebrae, in particular the 2nd-4th sacral segments and the 10th thoracic to the 2nd lumbar segments. One hypothesis is that mechanical dysfunction in these vertebrae causes decreased spinal mobility. This could affect the sympathetic nerve supply to the blood vessels supplying the pelvic viscera, leading to dysmenorrhoea as a result of vasoconstriction. Manipulation of these vertebrae increases spinal mobility and may improve pelvic blood supply through an influence on the autonomic nerve supply to the blood vessels. Another hypothesis is that dysmenorrhoea is referred pain arising from musculoskeletal structures that share the same pelvic nerve pathways. The character of pain from musculoskeletal dysfunction can be very similar to gynecological pain and can present as cyclic pain as it can also be altered by hormonal influences associated with menstruation.

OBJECTIVES

To determine the safety and efficacy of spinal manipulative interventions for the treatment of primary or secondary dysmenorrhoea when compared to each other, placebo, no treatment, or other medical treatment.

SEARCH STRATEGY

Electronic searches of the Cochrane Menstrual Disorders and Subfertility Group specialised register of controlled trials, CCTR, MEDLINE, EMBASE, CINAHL, Bio extracts, Psyclit and SPORTDiscus were performed to identify relevant randomised controlled trials (RCTs). The Cochrane Complementary Medicine Field's Register of controlled trials (CISCOM) was also searched. Attempts were also made to identify trials from the National Research Register, the Clinical Trial Register and the citation lists of review articles and included trials. In most cases, the first or corresponding author of each included trial was contacted for additional information.

SELECTION CRITERIA

Any RCTs including spinal manipulative interventions (e.g. chiropractic, osteopathy or manipulative physiotherapy) vs each other, placebo, no treatment, or other medical treatment were considered. Exclusion criteria were: mild or infrequent dysmenorrhoea or dysmenorrhoea from an IUD.

DATA COLLECTION AND ANALYSIS

Five RCTs were identified that fulfilled the inclusion criteria for this review. Four trials involving high velocity, low amplitude manipulation (HVLA), and one involving the Toftness manipulation technique were included. Quality assessment and data extraction were performed independently by two reviewers. Meta analysis was performed using odds ratios for dichotomous outcomes and weighted mean differences for continuous outcomes. Data unsuitable for meta-analysis were reported as descriptive data and were also included for discussion. The outcome measures were pain relief or pain intensity (dichotomous, visual analogue scales, descriptive) and adverse effects.

MAIN RESULTS

Results from the four trials of high velocity, low amplitude manipulation suggest that the technique was no more effective than sham manipulation for the treatment of dysmenorrhoea, although it was possibly more effective than no treatment. Three of the smaller trials indicated a difference in favour of HVLA, however the one trial with an adequate sample size found no difference between HVLA and sham treatment. There was no difference in adverse effects experienced by participants in the HVLA or sham treatment. The Toftness technique was shown to be more effective than sham treatment by one small trial, but no strong conclusions could be made due to the small size of the trial and other methodological considerations.

REVIEWER'S CONCLUSIONS

Overall there is no evidence to suggest that spinal manipulation is effective in the treatment of primary and secondary dysmenorrhoea. There is no greater risk of adverse effects with spinal manipulation than there is with sham manipulation.

CeReS-18, a cell regulatory sialoglycopeptide, inhibits proliferation and migration of rat vascular smooth muscle cells

CeReS-18, a cell regulatory sialoglycopeptide, has been shown to inhibit proliferation of a wide array of target cells. In the present study, the effect of CeReS-18 on vascular smooth muscle cell (SMC) proliferation was characterized in cultured rat aorta SMCs (A7r5). More extensively, the effect of CeReS-18 on platelet-derived growth factor (PDGF)-induced SMC migration was examined using a modified Boyden's chamber assay. CeReS-18 inhibits both SMC proliferation and migration in a concentration-dependent, calcium-sensitive, and reversible manner. Furthermore, cells preincubated with the inhibitor had an increased sensitivity to CeReS-18-mediated inhibition of SMC migration. Immunoprecipitation and in vitro phosphorylation assays demonstrated that MAP kinase activity was inhibited in the CeReS-18-treated cells and pretreatment with CeReS-18 suppressed the activation of MAP kinase stimulated by PDGF. However, it is not likely that the suppression of the MAP kinase pathway was directly responsible for the ability of CeReS-18 to inhibit migration of the rat aorta smooth muscle cells since a MEK-specific inhibitor, PD98059, did not influence A7r5 cell migration.

Osteonecrosis of the knee after arthroscopic surgery for meniscal tears and chondral lesions

PURPOSE

Avascular necrosis of the knee following arthroscopic surgery has been described. The purpose of this article is to report a large series of patients who developed avascular necrosis after arthroscopy of the knee in an effort to delineate casual factors and results of treatment.

TYPE OF STUDY

Case series.

METHODS AND MATERIALS

The charts, radiographs, and magnetic resonance imaging (MRI) scans of patients who developed osteonecrosis (ON) of the knee after routine arthroscopic surgery were reviewed. Only those patients with no evidence of ON on preoperative MRI performed 6 weeks or longer after symptom onset and who postoperatively developed ON confirmed by repeat MRI and/or by pathological testing (specimens obtained at subsequent total knee arthroplasty) were included in the study. Seven patients with average age of 60 years (range, 41 to 79 years) met these inclusion criteria.

RESULTS

The lesions noted at arthroscopy included 4 medial meniscus tears, 3 lateral meniscal tears, 6 chondromalacia of the medial femoral condyle, 2 chondromalacia of the medial tibial plateau, 1 chondromalacia of the lateral femoral condyle, 1 chondromalacia of the lateral tibial plateau, and 2 chondromalacia of the patella. The location of postarthroscopy ON correlated geographically with pre-existing pathology. All 7 patients had meniscal and/or chondral lesions addressed surgically in the compartment that subsequently developed ON. Six of the 7 patients had an adjacent ipsilateral meniscus tear treated with partial meniscectomy (4 medial, 2 lateral). In addition, of the 4 patients who developed ON of the medial femoral condyle, all had overlying chondromalacia, 3 of whom were treated with arthroscopic chondroplasty. Of the 2 patients with lateral meniscal tears, 1 developed ON of the lateral femoral condyle and the other developed ON of the lateral tibial plateau. Three patients went on to require total knee arthroplasty, and 2 high tibial osteotomy. One patient's ON resolved and another patient was lost to follow-up.

CONCLUSION

ON should be considered in patients who have worsening symptoms after arthroscopy of the knee. These findings suggest a possible relationship between arthroscopic treatment of chondral and meniscal lesions and later appearance of ON in some patients. The role of arthroscopy in the development of ON needs to be further studied. Those at risk are elderly patients with chondral and meniscus lesions.

Improved post-embedding immunocytochemistry of myelinated nervous tissue for electron microscopy

The particularly high lipid content of normal mature adult myelin sheaths, together with the light fixation protocols usually necessary to retain antigenicity, combine to make white matter nervous tissue an especially problematical subject for post-embedding immuno-electron microscopy using modern acrylic resins. Fixation and infiltration modifications to standard processing schedules for Lowicryl were found to greatly improve the embedding and therefore the resulting morphology. This in turn improved the signal to noise ratio by reducing the high non-specific backgrounds usually found in poorly infiltrated areas. Using Lowicryl HM20, we have been able to obtain satisfactory immunostaining for myelin basic protein with good retention of structural integrity in the myelin of both normal and lesioned adult cortico spinal tract.

CeReS-18 inhibits growth and induces apoptosis in human prostatic cancer cells

BACKGROUND

Polypeptide growth factors are positive and negative regulators of prostatic growth and function, and many positive regulators of growth in the prostate have been extensively studied. However, very few inhibitors of prostate cell proliferation have been identified. We have isolated a unique 18-kDa sialoglycopeptide (CeReS-18) which inhibits cell proliferation of three separate lines of human prostate cancer cells, as well as inducing cellular cytotoxicity via an apoptotic pathway unrelated to the Bcl-2 family of proteins.

METHODS

Cell cycle inhibition was analyzed by direct cell counts with a Coulter (Miami, FL) cell counter. Apoptotic cells were analyzed by electron microscopy, annexin V-fluorescein isothiocyanate (FITC) staining, fluorescence microscopy, and propidium iodide uptake measured with a fluorescence-activated cell sorter. Expression of the proteins of the Bcl-2 family was detected by Western blot analysis.

RESULTS

We found that CeReS-18 inhibits cell proliferation of androgen-responsive, LNCaP.FGC human prostate cancer cells, as well as of androgen-nonresponsive DU-145 and PC3 human prostate cancer cells. Furthermore a, fivefold increase over the inhibitory concentration of CeReS-18 elicited a cytotoxic response by all three cell lines. We thus characterized the cytotoxic mechanism as apoptotic in nature, and we measured the expression of several members of the Bcl-2 family in PC3 cells upon treatment with CeReS-18.

CONCLUSIONS

The data indicate that CeReS-18 is a potent inhibitor of cellular progression through the cell cycle by both androgen-responsive and androgen-nonresponsive human prostate cancer cells. In addition, treatment of both types of cells with increased concentrations of CeReS-18 induces cellular cytotoxicity, characterized as apoptosis.

Inhibition of cyclin D-cdk activity in cell cycle arrest of Swiss 3T3 cells by CeReS-18, a novel cell regulatory sialoglycopeptide

CeReS-18 is a unique negative regulator of cell proliferation with a wide array of target cells. To elucidate the mechanism by which CeReS-18 mediates cell growth inhibition, the possibility that CeReS-18 alters the function of G1 cyclins and their respective cyclin-dependent kinases (cdks) has been examined in mouse fibroblasts (Swiss 3T3) synchronized by CeReS-18. We show here that cyclin D-associated cdk activity is significantly inhibited in the CeReS-18-treated cells. Corresponding to the inhibited cdk function, we demonstrate a low expression of cyclin D in mid G1 determined by Western blot analysis, and cyclin D was greatly reduced in the immunocomplex recovered with antibody to cdk4 and cdk6. Previously, we have shown that the retinoblastoma susceptibility gene product (pRb), a key substrate of cyclin D-cdk complex, was maintained in the hypophosphorylated state in the CeReS-18-inhibited cells. We conclude here that cyclin D/cdk4,6/pRb is the major pathway by which CeReS-18 mediates cell cycle arrest.

The significance of pelvic ultrasound abnormalities detected on routine ultrasound scanning prior to assisted reproduction

OBJECTIVE

To determine the benefit of screening patients with pelvic ultrasound before commencing treatment with in vitro fertilization or gamete intra-fallopian transfer, as well as before each subsequent treatment cycle was performed.

SUBJECTS AND SETTING

Seven hundred and seventy-nine patients who were enrolled in the Royal Hospital for Women Fertility Group assisted reproduction program.

METHOD

A retrospective analysis was performed.

RESULTS

It was found that the majority of abnormalities were detected by the initial ultrasound. However, ultrasound contributed little to their diagnosis and management.

CONCLUSION

As a result of this review of pelvic ultrasound examinations performed, the policy of screening prior to the initial cycle of treatment will be continued to exclude significant ovarian tumors and to identify patients with polycystic ovaries, who are more likely to be stimulated to levels at which there is a risk of ovarian hyperstimulation syndrome. The policy of screening before each subsequent treatment cycle has been discontinued, since few additional abnormalities were detected.

The influence of advanced age on the outcome of assisted reproduction

PURPOSE

Our purpose was to determine the influence of age on the outcome of assisted reproduction, with particular interest in women aged 40 years or older.

METHODS

A retrospective review of the 779 patients enrolled in the Royal Hospital for Women Fertility Group fertility program between 1987 and 1994 was performed. The results for women aged 40 years or older were compared with those for women between 36 and 39 years and those younger than 36 years. The main outcome measures were pregnancy rate, pregnancy outcome, fertilization rate, and ovarian response.

RESULTS

Compared with those in younger women, pregnancy rate, pregnancy outcome, fertilization rate, and ovarian response to controlled ovarian stimulation were significantly worse in women aged 40 years or older.

CONCLUSIONS

The outcome of assisted reproduction in women of 40 years of age or older was extremely poor. Compared with those in younger women, pregnancy outcome and ovarian response to controlled ovarian stimulation were significantly worse in women of 40 years or more.

Physical fitness as a function of psychological and situational factors

The association between personality variables suggested by Rotter's social learning theory and indices of physical fitness was examined in a sample of U.S. college students. As predicted, both higher value placed on physical fitness and greater internal locus of control were related to selected indicators of physical fitness. In addition, gender of administrator affected performance on certain measures of physical fitness. The results suggest the need for longitudinal studies to evaluate the role of physical activity in mediating the relationship between personality variables and physical fitness.

Experimental gingivitis in periodontitis-susceptible subjects

The purpose of this study was to evaluate clinical, microbiological, and gingival crevicular fluid (GCF) profiles in periodontitis-resistant and periodontitis-susceptible subjects during 4 weeks of experimental gingivitis. Experimental groups of similar ages were defined as gingivitis controls (GC; n = 10) and history of rapidly progressive periodontitis (RPP; n = 10), respectively. Prior to baseline, all subjects achieved good plaque control (plaque index (P1I) approximately 0) and gingival health (gingival index (GI) = 0), and had probing depths < or = 4 mm on experimental teeth. For 4 weeks after baseline, oral hygiene around maxillary 2nd premolar and 1st molar teeth was inhibited by a plaque guard. The plaque guard was removed weekly for GCF sampling to determine interleukin (IL)-1 beta and prostaglandin (PG)E2 amounts by ELISAs. In addition, P1I, GI, probing depth, and gingival recession measurements were made. Subgingival plaque darkfield microscopy and DNA probe analysis also were performed. Results indicated that clinical signs of inflammation, microbiological patterns and GCF profiles progressed similarly in both groups. However, plaque accumulated more rapidly in the susceptible subjects. P1I in RPP at 4 weeks was 2.1 +/- 0.1 compared to 1.5 +/- 0.2 in GC, with an incidence of P1I > of 100% versus 50%, respectively (logistic regression; p < 0.0001). Hence, the clinical, microbiological and host factors selected for this study were unrelated to previous susceptibility to periodontitis when evaluated in the experimental gingivitis model. However, the increased rate of plaque accumulation, following thorough plaque removal, in RPP patients suggests a potential factor in disease recurrence in these susceptible subjects.

Cyclic loading of transosseous rotator cuff repairs: tension overload as a possible cause of failure

Previous experimental studies of failure of rotator cuff repair have involved a single pull to ultimate load. Such an experimental design does not represent the cyclic loading conditions experienced in vivo. We created 1 cm x 2 cm rotator cuff defects in 16 cadaver shoulders, repaired each defect with transosseous simple sutures, and cyclically loaded the repairs by a servohydraulic materials test system actuator at physiologic rates and loads (rate of 33 mm/sec to a load of 180 N.). A progressive gap was noted in each specimen, for a 100% rate of failure of the repairs. A 5 mm gap developed at an average of 25 cycles, and a 10 mm gap developed at an average of 188 cycles. The central suture always failed first and by the largest magnitude. This study suggests that rotator cuff tears that are repaired with a "tension overload" of a portion of the muscle-tendon units will undergo gradual failure with physiologic cyclic loading until the normal resting lengths of the muscle-tendon units are restored. This "controlled failure" of the repairs may explain residual defects that have been demonstrated by ultrasonography and by arthrography in patients with "successful" rotator cuff repairs. Clinical implications are that: 1) rotator cuff tears should be repaired without tension if possible; and 2) transosseous bone tunnels should ideally extend distal to the weak metaphysical bone so that purchase is obtained into cortical bone for greater fixation strength.

Inhibition of hormone and growth factor responsive and resistant human breast cancer cells by CeReS-18, a cell regulatory sialoglycopeptide

We have previously documented that CeReS-18, a cell regulatory sialoglycopeptide, inhibits the cellular proliferation of normal and transformed cell types from a diverse range of species. Most cell types studies exhibit a similar sensitivity to the reversible but growth inhibitory effects of CeReS-18 at 7 x 10(8) M concentration, while at higher concentrations CeReS-18 can elicit cytotoxicity. The present study was conducted to examine the effect of CeReS-18 on the proliferation of human mammary epithelial carcinoma cells. MCF-7 cells, which are estrogen receptor positive (ER+), and BT-20 cells, which are estrogen receptor negative (ER+), were utilized. Both cell lines show equal sensitivity to growth inhibition elicited by CeReS-18. Complete cessation of cell cycling was achieved with 7 x 10(-8) M CeReS-18, and the arrest was shown to be completely reversible. Flow cytometric analysis, performed on CeReS-18 treated cells from both cell types, revealed that the majority of these cells were arrested in the G1 phase of the cell cycle. When cells were treated simultaneously with inhibitor and stimulatory concentrations of mitogens such as epidermal growth factor (EGF), basic fibroblast growth factor (b-FGF), estrogen, insulin-like growth factors I and II (IGFI and IGFII), no alteration of the inhibitory activity of CeReS-18 was observed. CeReS-18 clearly abrogated the mitogenic activity that these growth factors elicited with human mammary carcinoma cells.

CeReS-18, a novel cell surface sialoglycopeptide, induces cell cycle arrest and apoptosis in a calcium-sensitive manner

Very few growth inhibitors have been identified which can inhibit the proliferation of a broad spectrum of human breast cancer cell lines. CeReS-18, a novel cell surface sialoglycopeptide growth inhibitor, can reversibly inhibit the proliferation of both estrogen receptor positive (MCF-7) and negative (BT-20) human breast cancer cell lines. In addition, at concentrations above those required for the reversible inhibition of cell proliferation, CeReS-18 can also induce cell death in MCF-7 cells. Changes in nuclear and cytoplasmic morphology, characteristic of apoptosis, were detected in MCF-7 cells treated with a cytotoxic concentration of CeReS-18, and internucleosomal DNA cleavage was also observed. The sensitivity of MCF-7 and BT-20 cells to the biological properties of CeReS-18 could be influenced by altering the calcium concentration in the extracellular growth medium, such that when the calcium concentration in the environment was decreased, and increased sensitivity to CeReS-18-induced growth inhibition and cytotoxicity were observed. The addition of the calcium chelating agent EGTA to MCF-7 cells, cultured in a normal calcium environment, could mimic the increased sensitivity to the biological effects of CeReS-18 observed under reduced calcium conditions.

Determination of 5-fluorouracil in human plasma by a simple and sensitive reversed-phase HPLC method

A simple and sensitive reversed-phase HPLC method with UV detection was developed and validated for the quantitation of 5-fluorouracil (5-FC) in human plasma. After acidification and salting out, 5-FU was extracted into ethyl acetate and back-extracted into a basic buffer. The extract was adjusted to neutral pH before being injected onto the HPLC column. 5-FU was separated from the matrix components on a YMC ODS-AQ column at 40 degrees C using an aqueous mobile phase of 10 mM potassium phosphate at pH 5.5. A linear gradient of 0-25% methanol wash eluted late peaks, maintained column performance, and increased column stability. The run time was 20 min. The linear range was 25-300 ng ml-1 (r2 > 0.999). The limit of quantitation was 25 ng ml-1, with a signal-to-noise ratio of 23:1. Interday precision and accuracy of quality control samples were 6.2-8.4% relative standard deviation and -0.1(-)+1.9% relative error.

Growth inhibition of BALB/c mouse keratinocytes by TGF-beta 1 and CeReS-18 appears to act through distinct mechanisms

Cell growth is controlled by the complex interactions of both positive and negative growth modulators. Studies were performed to directly compare the growth inhibitory properties of TGF-beta 1 and CeReS-18, a novel cell surface sialoglycopeptide growth inhibitor. Growth inhibition by CeReS-18 and that by TGF-beta 1 shared some similarities although significant differences were apparent. Similarities included a dose-responsive inhibition of BALB/c mouse keratinocyte (MK) cell proliferation that could be nontoxic and reversible. Both CeReS-18 and TGF-beta 1 could equally inhibit the stimulation of DNA synthesis induced by serum or keratinocyte growth factor in MK cells, and in both cases the inhibition was not due to decreased KGF binding to the target cell surface receptor. Inhibition of cell proliferation with CeReS-18, followed by an immediate reincubation with either CeReS-18 or TGF-beta 1, suggested that the sites of arrest mediated by both inhibitors were similar but not necessarily identical. However, recovery from CeReS-18-induced growth inhibition could be achieved by either removing the CeReS-18 or adding calcium directly to CeReS-18-inhibited MK cells, while recovery from TGF-beta 1-induced growth arrest could be reversed only by TGF-beta 1 removal. In addition, the sensitivity of MK cells to CeReS-18-induced cell cycle arrest could be altered by changing the extracellular calcium concentration, but sensitivity to TGF-beta 1 was unaffected by the calcium environment of the MK cells. While recovery from cell cycle arrest was rapid and complete with MK cell cultures inhibited with CeReS-18, removal of TGF-beta 1 led to a slower and incomplete recovery of cell cycling.

Late Pleistocene Desiccation of Lake Victoria and Rapid Evolution of Cichlid Fishes

Lake Victoria is the largest lake in Africa and harbors more than 300 endemic species of haplochromine cichlid fish. Seismic reflection profiles and piston cores show that the lake not only was at a low stand but dried up completely during the Late Pleistocene, before 12,400 carbon-14 years before the present. These results imply that the rate of speciation of cichlid fish in this tropical lake has been extremely rapid.

Purification and stability characterization of a cell regulatory sialoglycopeptide inhibitor

Previous attempts to physically separate the cell cycle inhibitory and protease activities in preparations of a purified cell regulatory sialoglycopeptide (CeReS) inhibitor were largely unsuccessful. Gradient elution of the inhibitor preparation from a DEAE HPLC column separated the cell growth inhibitor from the protease, and the two activities have been shown to be distinct and non-overlapping. The additional purification increased the specific biological activity of the CeReS preparation by approximately two-fold. The major inhibitory fraction that eluted from the DEAE column was further analyzed by tricine-SDS-PAGE and microbore reverse phase HPLC and shown to be homogeneous in nature. Two other fractions separated by DEAE HPLC, also devoid of protease activity, were shown to be inhibitory to cell proliferation and most likely represented modified relatives of the CeReS inhibitor. The highly purified CeReS was chemically characterized for amino acid and carbohydrate composition and the role of the carbohydrate in cell proliferation inhibition, stability, and protease resistance was assessed.

Role of calcium in growth inhibition induced by a novel cell surface sialoglycopeptide

Our laboratory has purified an 18 kDa cell surface sialoglycopeptide growth inhibitor (CeReS-18) from intact bovine cerebral cortex cells. Evidence presented here demonstrates that sensitivity to CeReS-18-induced growth inhibition in BALB-c 3T3 cells is influenced by calcium, such that a decrease in the calcium concentration in the growth medium results in an increase in sensitivity to CeReS-18. Calcium did not alter CeReS-18 binding to its cell surface receptor and CeReS-18 does not bind calcium directly. Addition of calcium, but not magnesium, to CeReS-18-inhibited 3T3 cells results in reentry into the cell cycle. A greater than 3-hour exposure to increased calcium is required for escape from CeReS-18-induced growth inhibition. The calcium ionophore ionomycin could partially mimic the effect of increasing extracellular calcium, but thapsigargin was ineffective in inducing escape from growth inhibition. Increasing extracellular calcium 10-fold resulted in an approximately 7-fold increase in total cell-associated 45Ca+2, while free intracellular calcium only increased approximately 30%. However, addition of CeReS-18 did not affect total cell-associated calcium or the increase in total cell-associated calcium observed with an increase in extracellular calcium. Serum addition induced mobilization of intracellular calcium and influx across the plasma membrane in 3T3 cells, and pretreatment of 3T3 cells with CeReS-18 appeared to inhibit these calcium mobilization events. These results suggest that a calcium-sensitive step exists in the recovery from CeReS-18-induced growth inhibition. CeReS-18 may inhibit cell proliferation through a novel mechanism involving altering the intracellular calcium mobilization/regulation necessary for cell cycle progression.

Calcium influences sensitivity to growth inhibition induced by a cell surface sialoglycopeptide

While studies concerning mitogenic factors have been an important area of research for many years, much less is understood about the mechanisms of action of cell surface growth inhibitors. We have purified an 18 kDa cell surface sialoglycopeptide growth inhibitor (CeReS-18) which can reversibly inhibit the proliferation of diverse cell types. The studies discussed in this article show that three mouse keratinocyte cell lines exhibit sixty-fold greater sensitivity than other fibroblasts and epithelial-like cells to CeReS-18-induced growth inhibition. Growth inhibition induced by CeReS-18 treatment is a reversible process, and the three mouse keratinocyte cell lines exhibited either single or multiple cell cycle arrest points, although a predominantly G0/G1 cell cycle arrest point was exhibited in Swiss 3T3 fibroblasts. The sensitivity of the mouse keratinocyte cell lines to CeReS-18-induced growth inhibition was not affected by the degree of tumorigenic progression in the cell lines and was not due to differences in CeReS-18 binding affinity or number of cell surface receptors per cell. However, the sensitivity of both murine fibroblasts and keratinocytes could be altered by changing the extracellular calcium concentration, such that increased extracellular calcium concentrations resulted in decreased sensitivity to CeReS-18-induced proliferation inhibition. Thus the increased sensitivity of the murine keratinocyte cell lines to CeReS-18 could be ascribed to the low calcium concentration used in their propagation. Studies are currently under way investigating the role of calcium in CeReS-18-induced growth arrest. The CeReS-18 may serve as a very useful tool to study negative growth control and the signal transduction events associated with cell cycling.

Selective cytotoxicity of transformed cells but not normal cells by a sialoglycopeptide growth regulator in the presence of tumor necrosis factor

The tumor necrosis factor-alpha (TNF)-resistant, SV40-transformed, murine fibroblast cell lines, F5b and F5m, became sensitive to TNF-mediated cytolysis after treatment with a biologically active 18 kDa peptide fragment (SGP) derived from a 66-kDa parental cell surface sialoglycoprotein. Neither TNF nor the SGP alone exhibited cytotoxicity to the two SV40-transformed cell lines. However, Balb/c 3T3 cells, incubated with SGP alone or with SGP and TNF, were not killed. Therefore, SGP can selectively sensitize cells for TNF alpha-mediated cytotoxicity. This selective sensitization may be due to the previously documented ability of the SGP to selectively mediate cell cycle arrest.

Cell proliferation inhibition in reduced gravity

Extended durations of spaceflight have been shown to be deleterious on an organismic level; however, mechanisms underlying cellular sensitivity to the gravitational environment remain to be elucidated. The majority of the gravitational studies to date indicates that cell regulatory pathways may be influenced by their gravitational environment. Still, few cell biology experiments have been performed in space flight and even fewer experiments have been repeated on subsequent flights. With flight opportunities on STS-50, 54, and 57, Sf9 cells were flown in the BioServe Fluids Processing Apparatus and cell proliferation was measured with and without exposure to a cell regulatory sialoglycopeptide (CeReS) inhibitor. Results from these flights indicate that the Sf9 cells grew comparable to ground controls, that the CeReS inhibitor bound to its specific receptor, and that its signal transduction cascade was not gravity sensitive.

Role of the retinoblastoma protein in cell cycle arrest mediated by a novel cell surface proliferation inhibitor

A novel cell regulatory sialoglycopeptide (CeReS-18), purified from the cell surface of bovine cerebral cortex cells has been shown to be a potent and reversible inhibitor of proliferation of a wide array of fibroblasts as well as epithelial-like cells and nontransformed and transformed cells. To investigate the possible mechanisms by which CeReS-18 exerts its inhibitory action, the effect of the inhibitor on the posttranslational regulation of the retinoblastoma susceptibility gene product (RB), a tumor suppressor gene, has been examined. It is shown that CeReS-18 mediated cell cycle arrest of both human diploid fibroblasts (HSBP) and mouse fibroblasts (Swiss 3T3) results in the maintenance of the RB protein in the hypophosphorylated state, consistent with a late G1 arrest site. Although their normal nontransformed counterparts are sensitive to cell cycle arrest mediated by CeReS-18, cell lines lacking a functional RB protein, through either genetic mutation or DNA tumor virus oncoprotein interaction, are less sensitive. The refractory nature of these cells is shown to be independent of specific surface receptors for the inhibitor, and another tumor suppressor gene (p53) does not appear to be involved in the CeReS-18 inhibition of cell proliferation. The requirement for a functional RB protein product, in order for CeReS-18 to mediate cell cycle arrest, is discussed in light of regulatory events associated with density-dependent growth inhibition.

Negative regulators of cell proliferation

Cell proliferation is governed by the influence of both mitogens and inhibitors. Although cell contact has long been thought to play a fundamental role in cell cycling regulation, and negative regulators have long been suspected to exist, their isolation and purification has been complicated by a variety of technical difficulties. Nevertheless, over recent years an ever-expanding list of putative negative regulators have emerged. In many cases, their biological inhibitory activities are consistent with density-dependent growth inhibition. Most likely their interactions with mitogenic agents, at an intracellular level, are responsible for either mitotic arrest or continued cell cycling. A review of naturally occurring cell growth inhibitors is presented with an emphasis on those factors shown to be residents of the cell surface membrane. Particular attention is focused on a cell surface sialoglycopeptide, isolated from intact bovine cerebral cortex cells, which has been shown to inhibit the proliferation of an unusually wide range of target cells. The glycopeptide arrest cells obtained from diverse species, both fibroblasts and epithelial cells, and a broad variety of transformed cells. Signal transduction events and a limited spectrum of cells that are refractory to the sialoglycopeptide have provided insight into the molecular events mediated by this cell surface inhibitor.

Changes in sciatic nerve and spinal cord function induced by a CNS viral infection

Electrophysiologic response characteristics of mouse sciatic nerve and spinal cord were investigated following CNS infection with the temperature-sensitive (ts) vesicular stomatitis virus (VSV) mutant G31 KS5. Measurements were obtained before clinical symptoms of the virus-induced CNS disease appeared. Sciatic nerve peak conduction velocities were not different between virus and control inoculated groups. For all control groups, sciatic nerve response (SNR) recovery, characterized by the amplitude ratio of double pulse-evoked responses, followed a facilitation-depression time course. By 4 days after VSV inoculation, the time course of SNR recovery changed with the SNR amplitude ratios significantly depressed compared to control. Crossed spinal responses (CSRs) were measured from one sciatic nerve in response to stimulation of the contralateral sciatic nerve. For all control groups, CSR recovery, as characterized by area ratios calculated from single and double pulse evoked responses, followed a facilitation-depression time course. By 5 days after VSV inoculation, the time course of CSR recovery changed with the CSR area ratios significantly depressed compared to control. The results show that simple electrophysiologic techniques can be used to detect virus-induced changes in sciatic nerve and spinal cord previously undetectable by clinical measures.

The identification of a naturally occurring cell surface growth inhibitor related to a previously described bovine sialoglycopeptide

A 66-kDa sialoglycoprotein has been identified as the parental membrane molecule of an earlier described sialoglycopeptide (SGP), an 18-kDa molecule released by protease treatment of intact bovine cerebral cortex cells that was shown to be a potent inhibitor of cellular proliferation. The 66-kDa parental sialoglycoprotein (p-SGP) was purified approximately 2,400-fold, to apparent homogeneity, from bovine cerebral cortex cell membranes by its release during incubation with 3 M NaCl, preparative isoelectric focusing and lectin affinity chromatography. Although a membrane-associated molecule, the p-SGP appeared to be tightly bound to the cell membrane, since it was not released during incubations in the absence of 3 M NaCl. Incubation of the membrane preparations with 3 M urea proved to be too harsh, and the antigenicity required to follow the purification of the p-SGP was abolished. Analyses by SDS-PAGE, under reducing and nonreducing conditions, suggested that the p-SGP membrane component was a single polypeptide without subunit structure. The p-SGP was shown to be structurally related to the SGP fragment by immunoblots with IgG raised to the SGP inhibitor, and functionally related to the SGP by its ability to inhibit Swiss 3T3 proliferation at concentrations strikingly similar to that previous measured with the SGP fragment.

Transferred T lymphocytes are compromised when the donor is pretreated with beta-endorphin

A single intracerebroventricular (i.c.v.) injection of 14 pmol of beta-endorphin into 6-7-week-old BALB/c (+/+) donor mice, 24 h prior to isolation of their T lymphocytes for use for reconstitution of athymic BALB/c (nu/nu) nude mice, altered the immuno-protective effect of adoptive transfer against an intracerebral (i.c.) infection with a temperature-sensitive mutant of vesicular stomatitis virus (tsG31 KS5 VSV). Simultaneous injection of beta-endorphin and naloxone into donor animals negated the opiate effects on splenic lymphocytes. T lymphocytes, isolated from beta-endorphin-treated donors, and then depleted with anti-asialo GM1 antiserum and complement failed to demonstrate the detrimental effects of beta-endorphin.

The use of the tyrosine phosphatase antagonist orthovanadate in the study of a cell proliferation inhibitor

Incubation of murine fibroblasts with orthovanadate, a global tyrosine phosphatase inhibitor, was shown to confer a "pseudo-transformed" phenotype with regard to cell morphology and growth characteristics. This alteration was manifested by both an increasing refractile appearance of the cells, consistent with many transformed cell lines, as well as an increase in maximum cell density was attained. Despite the abrogation of cellular tyrosine phosphatase activity, orthovanadate-treated cells remained sensitive to the biological activity of a naturally occurring sialoglycopeptide (SGP) cell surface proliferation inhibitor. The results indicated that tyrosine phosphatase activity, inhibited by orthovanadate, was not involved in the signal transduction pathway of the SGP.

Virus protein assembly in microgravity

The coat of polyomavirus is composed of three proteins that can self-assemble to form an icosahedral capsid. VP1 represents 75% of the virus capsid protein and the VP1 capsomere subunits are capable of self assembly to form a capsid-like structure. Ground-based and orbiter studies were conducted with VP1 protein cloned in an expression vector and purified to provide ample quantities for capsomere-capsid assembly. Flight studies were conducted on STS-37 on April 5-9, 1991. Assembly initiated when a VP1 protein solution was interfaced with a Ca+2 buffer solution (pH 5.0). After four days a second alignment terminated the assembly process and allowed for glutaraldehyde fixation. Flight and ground-based samples were analyzed by electron microscopy. Ground-based experiments revealed the assembly of VP1 into capsid-like structures and a heterogenous size array of capsomere subunits. Samples reacted in microgravity, however, showed capsomeres of a homogenous size, but lack of capsid-like assembly.

An immune cell population that responds to beta-endorphin and is responsible for protecting nude mice from the fatal consequences of a virus infection of the central nervous system

Reconstitution of 3- to 4-week-old BALB/c nude (nu/nu) mice with 10(7) syngeneic splenocytes, 48 h before intracerebral inoculation with a temperature-sensitive (ts) mutant of VSV (tsG31 KS5), provided protection from the fatal consequences of clinical disease in 80-90% of the infected animals. Reconstitution of animals with 10(7) splenocytes, first depleted of natural killer (NK) cells with anti-asialo GM1 and complement, also afforded protection against the infectious disease. Depletion of T-lymphocytes with anti-thy-1.2 antibody and complement, however, provided little protection with approximately 40% of the animals succumbing to the virus infection within 30 days post-infection. A single intracerebroventricular injection with 14 pM of beta-endorphin, 24 h prior to viral infection, led to an increased fatality of mice previously reconstituted with T-lymphocytes but not in animals receiving only syngeneic NK cells. The increased fatality caused by the neuropeptide was antagonized by naloxone but not beta-endorphin-(1-27). Separation of splenocyte cell populations by buoyant density centrifugation demonstrated that small race lymphocytes, and not the large granular lymphocytes, were responsible for protection of nude mice from the central nervous system infection with ts-VSV. The beta-endorphin-responsive immune cells were shown to be a minor fraction of the small race T-lymphocyte population that bear the asialo-GM1 marker.

Identification of a cell surface component of Swiss 3T3 cells associated with an inhibition of cell division

Polyclonal IgG, prepared to a purified bovine cell surface sialoglycopeptide (SGP) inhibitor of cell division, was used to identify an antigenically related molecule on the surface of Swiss 3T3 cells. SDS-PAGE and Western analyses showed that the anti-SGP antibody was monospecific and primarily recognized a 66-kDA protein of 3T3 cell membranes. Treatment of intact 3T3 cells or 3T3 cell membranes with either broad and phosphatidylinositol-specific phospholipase C enzymes suggested that the antigenic material most likely existed as an integral membrane molecule, or associated as a multimeric complex, and was not anchored at the cell surface by a phospholipid. The addition of anti-SGP IgG to 3T3 cell monolayer cultures was shown to promote cell division, suggesting a regulatory function for the membrane-associated molecule.

Modulation of growth-related gene expression and cell cycle synchronization by a sialoglycopeptide inhibitor

When an 18-kDa cell surface sialoglycopeptide (SGP), isolated from intact bovine cerebral cortex cells, was incubated with exponentially growing Swiss 3T3 cells, cell proliferation was efficiently arrested. The inhibition was totally reversible since after removal of the SGP the arrested cells resumed their progress in the cell cycle in a synchronized manner for at least two divisions. Readdition of the GSP 4 h after reversal of the inhibition did not, however, affect the commitment of the cells to advance through metaphase, although progress through the cell cycle was once again inhibited after the cells reentered the G1 phase. The efficient nature of the SGP-mediated cell cycle arrest in G1 provided us with a basis to examine potential changes in the expression of several competence genes, and genes associated with mid and late G1, that have been implicated in cell cycle progression. Upon serum stimulation of quiescent Swiss 3T3 cells, the induction of c-myc and c-fos expression was not influenced by the SGP at concentrations highly inhibitory to cell cycling. Expression of JE was induced by serum, and the presence of the SGP had little effect on the expression of this growth-related gene. KC expression was not appreciably stimulated by serum although, surprisingly, the addition of the SGP resulted in a significant increase in expression. In addition, we learned that the SGP did not alter expression of ornithine decarboxylase, c-ras, or thymidine kinase, which are induced later than the genes associated with the initial stages of competence.

Effects of a sialoglycopeptide on early events associated with signal transduction

A sialoglycopeptide (SGP), isolated and purified from bovine cerebral cortex cells, was studied in regard to early signal transduction events associated with the cell cycle. Previously shown to be a potent antagonist to a variety of mitogens, the SGP abrogated the ability of 12-O-tetradecanoylphorbol-13 acetate (TPA) to elicit an alkalinization of 3T3 cell cytosol, but only when added minutes prior to, or simultaneously with, the tumor promoter. 3T3 cell TPA-mediated Ca2+ mobilization was also inhibited by the SGP although the inhibitor itself did not bind Ca2+ in a cell-free assay. The results are discussed in light of the already known kinetics of interaction between the SGP, various mitogens, and the calcium ionophore A23187 with regard to the pivotal events leading to the decision of a cell to divide or not to divide.

Physical fitness, body image, and locus of control in college women dancers and nondancers

This study assessed the correlations among measures of physical fitness, body image and locus of control in college freshman women dancers and nondancers. 39 students enrolled in courses in modern, ballet, and jazz dance, and 120 students enrolled in an introductory personal health course were administered the Hall Physical Fitness Test Profile, the Winstead and Cash 54-item short-form Body Self-relations Questionnaire (BSRQ), and the Adult Nowicki-Strickland Locus of Control Scale. Analysis showed dancers were more physically fit, scored more positively on the BSRQ physical fitness and health domains, and were more internal in their locus of control than the nondancers. There was no significant difference between dancers and nondancers on the BSRQ appearance domain. The significant positive correlation between BSRQ health and physical fitness among dancers was not observed among nondancers. The significant positive correlation for BSRQ appearance and health was noted for nondancers but not for dancers.

Cell cycle arrest and cellular differentiation mediated by a cell surface sialoglycopeptide

Cell cycling by a relatively wide variety of cell lines was shown to be reversibly inhibited by a cell surface sialoglycopeptide (SGP) isolated and purified from intact bovine cerebral cortex cells. Cell cycle arrest, mediated by the bovine SGP inhibitor, was shown to be completely reversible with mouse Swiss 3T3, mouse 1316 fibrosarcoma, mouse N2a neuroblastoma, bovine MDBK and monkey BSC-1 cells. These cell lines represented both fibroblast and epithelial-like cells, transformed and nontransformed cells, as well as their being derived from a broad array of species. In contrast to the others tested, human HL-60 leukemic cells were sensitive to the inhibitory effects of the SGP but did not reenter the mitotic cycle after the removal of the inhibitor. Instead, the mitotic arrest of HL-60 cells appeared to enhance entry into a terminal and irreversible state of cellular differentiation.

Incentives and their influence on appointment compliance in a teenage family-planning clinic

The purpose of this study was to ascertain whether or not the family-planning compliance patterns of indigent adolescents could be influenced by various types of incentives. From February 1988 through January 1989, 534 postpartum inner city teenagers, aged 12-19, who delivered at a large city-county public hospital, participated. Teens were randomly assigned to two treatment groups that either offered a coupon for milk for the infant or a gift for the teenage mother if they returned for their postpartum visit 4-6 weeks after delivery. A third group, which used no incentive for appointment keeping, acted as a control. Although overall compliance was low, a significant relationship was found between type of program incentive and compliance outcome. The program using milk coupons as an incentive had the best compliance rate. This incentive appeared to be most effective with black adolescents. Such incentive programs, although not without controversy, offer a potential way to enhance postpartum contraceptive appointment-keeping compliance in a high-risk population.

Beta-endorphin alters the course of central nervous system disease induced by a temperature-sensitive vesicular stomatitis virus in reconstituted nude mice

A 100 plaque forming unit (pfu) dose of a temperature-sensitive (ts) mutant of vesicular stomatitis virus (VSV), tsG31 KS5, engendered a slowly progressive paralytic central nervous system (CNS) disease that killed all BALB/c nude mice within 28 days. Reconstitution of nude mice with 10(7) syngeneic splenocytes 24 h before intracerebral inoculation with tsG31 KS5 VSV, however, protected 92% of the animals from death. When these reconstituted animals were injected intracerebroventricularly with 14 pmol of beta-endorphin 24 h after reconstitution with splenocytes and 24 h before inoculation with tsG31 KS5 VSV, only 72% of the animals survived. Furthermore, whereas 40% of the afflicted reconstituted nude mice given intracerebroventricular injections of sterile water were able to recover from the symptoms of disease, those surviving animals which received beta-endorphin were unable to do so. A single intravenous injection of 14 pmol beta-endorphin, or repeated postinfection administration of 28 pmol of beta-endorphin intravenously into nude mice reconstituted with syngeneic splenocytes, which were pretreated with beta-endorphin, did not alter the course of CNS disease induced by tsG31 KS5 VSV. The effect induced by intracerebroventricular injection of beta-endorphin was antagonized by naloxone, but not by the neuropeptide fragment beta-endorphin-(1-27). A simultaneous intracerebroventricular injection of reconstituted nude mice with 1220 pmol of naloxone and 14 pmol of beta-endorphin resulted in a 89% survival rate, and 33% of the afflicted animals were able to overcome the symptoms of the disease induced by tsG31 KS5 VSV. Intracerebroventricular injection of reconstituted nude mice with 330 pmol of beta-endorphin-(1-27) and 14 pmol of beta-endorphin resulted in a 72% survival rate and the surviving animals were unable to improve appreciably the clinical status of their disease. Injection of reconstituted nude mice with either 1220 pmol of naloxone or 330 pmol of beta-endorphin-(1-27) alone did not alter the course of the CNS disease in any way. A single intracerebroventricular injection of 29 pmol of another psychoactive peptide, [Des-Tyr]-endorphin, 24 h after reconstitution of nude mice with splenocytes and 24 h prior to infection with virus, resulted in 74% survival; and 39% of the afflicted animals were able to recover from the clinical symptoms.