LipidSIM: Inferring mechanistic lipid biosynthesis perturbations from lipidomics with a flexible, low-parameter, Markov modeling framework

Lipid metabolism is a complex and dynamic system involving numerous enzymes at the junction of multiple metabolic pathways. Disruption of these pathways leads to systematic dyslipidemia, a hallmark of many pathological developments, such as nonalcoholic steatohepatitis and diabetes. Recent advances in computational tools can provide insights into the dysregulation of lipid biosynthesis, but limitations remain due to the complexity of lipidomic data, limited knowledge of interactions among involved enzymes, and technical challenges in standardizing across different lipid types. Here, we present a low-parameter, biologically interpretable framework named Lipid Synthesis Investigative Markov model (LipidSIM), which models and predicts the source of perturbations in lipid biosynthesis from lipidomic data. LipidSIM achieves this by accounting for the interdependency between the lipid species via the lipid biosynthesis network and generates testable hypotheses regarding changes in lipid biosynthetic reactions. This feature allows the integration of lipidomics with other omics types, such as transcriptomics, to elucidate the direct driving mechanisms of altered lipidomes due to treatments or disease progression. To demonstrate the value of LipidSIM, we first applied it to hepatic lipidomics following Keap1 knockdown and found that changes in mRNA expression of the lipid pathways were consistent with the LipidSIM-predicted fluxes. Second, we used it to study lipidomic changes following intraperitoneal injection of CCl4 to induce fast NAFLD/NASH development and the progression of fibrosis and hepatic cancer. Finally, to show the power of LipidSIM for classifying samples with dyslipidemia, we used a Dgat2-knockdown study dataset. Thus, we show that as it demands no a priori knowledge of enzyme kinetics, LipidSIM is a valuable and intuitive framework for extracting biological insights from complex lipidomic data.

Another Failure to Obtain Negative Incentive Contrast following Reductions in Sucrose Reward

The effects of reductions in volume only, concentration only, and volume plus concentration of sucrose rewards were studied in a discrete-trial (retractable bar) situation. There was no evidence of abrupt behavioral decrements or negative contrast effects associated with any type of reward reduction. The present results are in opposition to those obtained following variations in solid food rewards. These findings suggest that the effects of sucrose and solid food manipulations require different theoretical interpretations.

Measurements of double-polarized compton scattering asymmetries and extraction of the proton spin polarizabilities

The spin polarizabilities of the nucleon describe how the spin of the nucleon responds to an incident polarized photon. The most model-independent way to extract the nucleon spin polarizabilities is through polarized Compton scattering. Double-polarized Compton scattering asymmetries on the proton were measured in the Δ(1232) region using circularly polarized incident photons and a transversely polarized proton target at the Mainz Microtron. Fits to asymmetry data were performed using a dispersion model calculation and a baryon chiral perturbation theory calculation, and a separation of all four proton spin polarizabilities in the multipole basis was achieved. The analysis based on a dispersion model calculation yields γ(E1E1)=-3.5±1.2, γ(M1M1)=3.16±0.85, γ(E1M2)=-0.7±1.2, and γ(M1E2)=1.99±0.29, in units of 10(-4)  fm(4).

Participant satisfaction with group and individual components of Adolescent Impact: a secondary prevention intervention for HIV-positive youth

Adolescent Impact, a developmentally targeted behavioral intervention aimed at decreasing risk behaviors and promoting health care adherence, was delivered to 83 HIV-infected youth, aged 13-21 years, receiving care in five urban HIV centers. Participants completed a patient satisfaction survey following the 12 part intervention consisting of seven groups and five individual sessions. A feedback questionnaire was also completed during each group session to gain more insight on participant experiences. Several indicators suggested high levels of satisfaction. First, overall attendance was relatively high. Second, participants rated their subjective experience and group content favorably. No differences in satisfaction ratings emerged between perinatally infected adolescents and those who acquired HIV through risk behaviors. However, differences emerged regarding perceived intervention utility and content-specific preferences. Findings suggest that Adolescent Impact participants were satisfied with the intervention and that a heterogeneous group of HIV-infected youth could be advantageously integrated into the same secondary prevention program.

Surface plasmon-polariton mediated light emission through thin metal films

The emission of light by sources in close proximity to a thin metallic film is dominated by surface plasmon-polariton modes supported by that film. We explore the nature of the modes and examine how the energy lost to such modes can be recovered. Both cross-coupled and coupled SPPs are presented as a means of transferring energy across a thin metal film. These modes are then scattered and thereby coupled to light by a wavelength scale grating type microstructure. We show that the photoluminescence emission from a structure containing a microstructured thin metal film that supports coupled SPPs is over 50 times greater than that from a similar planar structure. Similar strong photoluminescence emission is also exhibited by a sample that contains a planar metal film coated with a microstructured dielectric overlayer.

Functional nicotinic acetylcholine receptor expression on stem and progenitor cells of the early embryonic nervous system

Although the adult brain contains nicotinic acetylcholine (ACh) receptors vital to cortical function, little is known about the assembly of embryonic receptor subunits into functional receptors or their role in fetal brain development. We now report the first evidence of functional nicotinic ACh receptors on stem and progenitor cells of fetal mouse cerebral cortex as early as embryonic day 10.

Alterations of myocardial dynamic stiffness implicating abnormal crossbridge function in human mitral regurgitation heart failure

Mitral regurgitation (MR) causes ventricular dilation, a blunted myocardial force-frequency relation, and increased crossbridge force-time integral (FTI). The mechanism of FTI increase was investigated using sinusoidal length perturbation analysis to compare crossbridge function in skinned left ventricular (LV) epicardial muscle strips from 5 MR and 5 nonfailing (NF) control hearts. Myocardial dynamic stiffness was modeled as 3 parallel viscoelastic processes. Two processes characterize intermediate crossbridge cycle transitions, B (work producing) and C (work absorbing) with Q(10)s of 4 to 5. No significant differences in moduli or kinetic constants of these processes were observed between MR and NF. The third process, A, characterizes a nonenzymatic (Q(10)=0.9) work-absorbing viscoelasticity, whose modulus increases sigmoidally with [Ca(2+)]. Effects of temperature, crossbridge inhibition, or variation in [MgATP] support associating the calcium-dependent portion of A with the structural "backbone" of the myosin crossbridge. Extension of the conventional sinusoidal length perturbation analysis allowed using the A modulus to index the lifetime of the prerigor, AMADP crossbridge. This index was 75% greater in MR than in NF (P=0.02), suggesting a mechanism for the previously observed increase in crossbridge FTI. Notably, the A-process modulus was inversely correlated (r(2)=0.84, P=0.03) with in vivo LV ejection fraction in MR patients. The longer prerigor dwell time in MR may be clinically relevant not only for its potential role as a compensatory mechanism (increased economy of tension maintenance and increased resistance to ventricular dilation) but also for a potentially deleterious effect (reduced elastance and ejection fraction).

Functional nicotinic acetylcholine receptor expression in stem and progenitor cells of the early embryonic mouse cerebral cortex

The adult cerebral cortex contains nicotinic acetylcholine (ACh) receptors vital to cortical function. However, little is known about the assembly of embryonic nicotinic receptor subunits into functional receptors or whether they play an active role in cortical development. We now report evidence of functional nicotinic acetylcholine receptor channels in fetal mouse cerebral cortex as early as embryonic day 10 (E10), when the cortex consists of dividing stem and progenitor cells. Patch-clamp electrophysiological measurements indicate that nicotine and ACh evoke sizable inward currents characteristic of nicotinic receptors, that are strongly rectifying with a reversal potential near 0 mV. Three different nicotinic agonists, ACh, nicotine, and dimethylphenylpiperazinium, evoked cytosolic Ca(2+) signals. Agonist-evoked Ca(2+) signals and electrophysiological responses were found in greater than 70% of all E10-E11 cells tested and were blocked by nicotinic receptor antagonists. The Ca(2+) response to nicotinic agonists was markedly prolonged in cells from early embryonic stages relative to later stages of development. alpha3, alpha4, and alpha7 receptor subunit proteins were detected immunocytochemically in cortical cells from E10 to birth. The incidence of each subunit declined with embryonic age, suggesting a role in early development. We discuss the possible function of nicotinic receptors in early cortical development and their role as a target for nicotine in the developmental pathologies associated with the fetal tobacco syndrome.

Dynamics of histamine H(3) receptor antagonists on brain histamine metabolism: do all histamine H(3) receptor antagonists act at a single site?

Thioperamide, the prototypical histamine H(3) receptor antagonist, acts at the brain histamine H(3) autoreceptor to promote the release and metabolism of neuronal histamine, resulting in higher brain levels of the metabolite tele-methylhistamine. However, unlike thioperamide, several new histamine H(3) receptor antagonists enter the central nervous system (CNS), block brain histamine H(3) receptors and increase histamine release without increasing brain tele-methylhistamine levels. Experiments were performed presently in an attempt to understand these results. Consistent with previous findings, thioperamide significantly increased the content and synthesis rate of tele-methylhistamine in mouse and rat brain. In contrast, the histamine H(3) receptor antagonists GT-2227 (4-(6-cyclohexylhex-cis-3-enyl)imidazole) and clobenpropit did not affect tele-methylhistamine synthesis rate in mouse whole brain. The histamine H(3) receptor ligand GT-2016 (5-cyclohexyl-1-(4-imidazol-4-ylpiperidyl)pentan-1-one) had no effect on tele-methylhistamine levels in any rat brain region and decreased tele-methylhistamine synthesis rates in the mouse whole brain. To examine the possibility that these histamine H(3) receptor antagonists might prevent the methylation of newly released histamine, they were co-administered with thioperamide to determine their effects on the thioperamide-induced stimulation of tele-methylhistamine synthesis. GT-2016 significantly reduced the thioperamide-induced activation of tele-methylhistamine synthesis in mouse whole brain and in several regions of rat brain. Although further clarification is needed, these results suggest that some histamine H(3) receptor antagonists may promote the release of neuronal histamine, but also act to reduce histamine methylation in vivo by an unknown mechanism.

NMDA-mediated activation of the medial amygdala initiates a downstream neuroendocrine memory responsible for pseudopregnancy in the female rat

In female rats, genitosensory stimulation received during mating initiates twice-daily prolactin (PRL) surges, a neuroendocrine response that is the hallmark of early pregnancy or pseudopregnancy (P/PSP). Nocturnal and diurnal PRL surges are expressed repeatedly for up to 2 weeks after copulation, suggesting that a neuroendocrine memory for vaginocervical stimulation (VCS) is established at the time of mating. These studies investigated whether the processing and retention of VCS involves acute glutamatergic activation or de novo protein synthesis within the medial nucleus of the amygdala (MEA), a VCS-responsive brain site that is implicated in P/PSP initiation. Pharmacological activation of the MEA with the glutamate agonist, NMDA, initiated nocturnal PRL surges, causing a PSP state in females that had not received VCS. P/PSP initiation by mating was prevented by intra-amygdalar infusion of the NMDA receptor antagonist, 2-amino-5-phosphonopentanoic acid (AP-5), provided that it was administered before mating. AP-5 treatment also disrupted mating-induced c-fos expression in the principle bed nucleus of the stria terminalis and the ventrolateral division of the ventromedial hypothalamic nucleus, but not in the medial or anteroventral periventricular preoptic nuclei. Neither P/PSP nor downstream cellular activation was prevented when a protein synthesis inhibitor, anisomycin, was administered to the MEA. The results indicate that MEA cells are critical to the early processing of VCS through NMDA channel activation, rapidly conveying information to downstream hypothalamic cell groups that modulate neuroendocrine function.

Risk factors for rapid-onset cervical cancer

OBJECTIVES

The current study was designed to elucidate risk factors associated with the development of cervical cancer during the course of routine Papanicolaou smear screening (rapid-onset cervical cancer).

STUDY DESIGN

Four hundred eighty-three women diagnosed with invasive cervical cancer, representing 73% of all such tumors diagnosed in Connecticut between 1985 and 1990, were studied. Papanicolaou smear screening and risk factor information was obtained by questionnaire and physician record review. Results from human papillomavirus deoxyribonucleic acid testing by polymerase chain reaction of tumor samples were available for 278 study participants. Prediagnostic Papanicolaou smear slides were reviewed for 67% of cases with a screening history. Screening history information, slide review, and questionnaire data were used to classify women as having rapid-onset cervical cancer (n = 43), possible rapid-onset cervical cancer (n = 111), or normal-onset cervical cancer (n = 329).

RESULTS

Compared with normal-onset cases, rapid-onset cases tended to be younger (P =.001) and were more likely to be white (P =.002), diagnosed with adenocarcinomas or adenosquamous carcinomas (P =.001), and diagnosed with early-stage disease (P =.001). Cases diagnosed as possible rapid-onset disease tended to have a profile that was intermediate to that observed for rapid-onset and normal-onset cases. Human papillomavirus deoxyribonucleic acid was detected in 75.2% of cases tested. Compared with women who tested positive for human papillomavirus type 16 or other, those positive for human papillomavirus type 18 had a relative risk for rapid-onset disease of 1.6 (95% confidence interval 0.52-4.9). No significant association was observed between type 18 and possible rapid-onset disease when possible rapid-onset cases were compared with women diagnosed with normal-onset cervical cancer (relative risk 0.67, 95% confidence interval 0.29-1.6). Oral contraceptive use, cigarette smoking, number of pregnancies, and a maternal history of cervical cancer were not significantly associated with rapid-onset disease.

CONCLUSIONS

Results from this study suggest that the risk factors associated with the development of rapid-onset cervical cancer are similar to those for normal-onset disease.

Phase II trial of vinorelbine in recurrent and progressive epithelial ovarian cancer

OBJECTIVE

A phase II, multicenter trial was conducted to define the efficacy and safety of vinorelbine (Navelbine (vinorelbine tartrate) injection, NVB) in the treatment of advanced epithelial ovarian cancer (EOC).

METHODS

Patients with persistent or recurrent EOC who had received one prior platinum-based chemotherapy regimen were eligible. NVB was administered at 30 mg/m2 as a weekly outpatient intravenous infusion.

RESULTS

Using an intent-to-treat analysis of the 38 patients who received at least one dose, 11(29%, 95% confidence limits 15-46%) objective responses (4 complete, 7 partial) were observed. The median duration of response was 19 weeks. For all 38 patients, the median time to treatment failure and median survival were 12 and 60 weeks, respectively. Four of the 12 patients with platinum-resistant disease responded, while 7 of the 24 patients with platinum-sensitive disease responded. Toxicity was evaluable in all 38 patients. During course 1, 15 patients required dose reduction and 21 required dose delays. Grade 3-4 granulocytopenia occurred in 23 (62%) of 37 reporting patients. Grade 3-4 anemia and thrombocytopenia occurred in 16 and 5%, respectively. The most common nonhematologic toxicities were nausea (grade 3 or less, in 34%), constipation (grade 3 or less, in 29%), and asthenia (grade 2 or less, in 24%). No life-threatening adverse effects were reported.

CONCLUSIONS

NVB is an effective, palliative agent for women with recurrent EOC. Dose-limiting granulocytopenia is substantial, yet manageable.

Tamoxifen in platinum-refractory ovarian cancer: a Gynecologic Oncology Group Ancillary Report

There is a critical need to find additional effective therapies in the management of ovarian cancer. A previously reported Gynecologic Oncology Group trial demonstrated that tamoxifen is an active drug when used in the salvage setting in this malignancy. Unfortunately, this original report did not specifically examine the utility of tamoxifen in patients with clinically defined platinum-refractory disease. In this reanalysis of the results of treatment of 102 evaluable patients entered into this multi-institutional trial, an objective response rate of 13% (95% confidence interval, 6.4-22.6%) was observed in patients with cisplatin-refractory ovarian cancer. The median response duration in this patient population was 4.4 months (range 1.2-9.2 months). Although the response rate is modest, this well-tolerated hormonal agent is a reasonable therapeutic option in selected patients with ovarian cancer when salvage therapy is to be considered. A possible role for this hormonal agent in other clinical settings in ovarian cancer will need to be defined through the conduct of carefully designed randomized clinical trials.

Intraperitoneal therapy administered through a Groshong catheter

This report describes a new device for delivery of intraperitoneal therapy. From October 1989 through March 1991, 27 externally accessed Groshong (Bard Access Systems, UT) catheters were placed transabdominally into 24 patients with presumed epithelial ovarian cancer at the conclusion of primary or second-look laparotomy. Total duration of catheter use was 81 months (range, 1-62 weeks). Fifty-seven cycles of intraperitoneal therapy were administered through 18 catheters (range, 1-11). Nine catheters were removed without being used after patients randomized off intraperitoneal treatment arms or were ineligible for intraperitoneal protocols. There were no complications associated with catheter placement or removal. None of the catheters became obstructed or dislodged while in place. There were no cases of infectious peritonitis, although one patient developed an exit-site skin infection. Surgery is not required to remove the Groshong catheter which fosters empiric placement of the device at the time of laparotomy in all patients potentially eligible for intraperitoneal therapy. The device-related infection rate of 4.2 per 100 patients is similar to that described using other implanted devices. Catheter maintenance is easy and patient acceptance is good. The Groshong catheter is a safe, reliable, and acceptable means of delivering intraperitoneal therapy.

Determinants of genital human papillomavirus infection in low-income women in Washington, D.C

OBJECTIVES

To confirm the risk factors for genital human papillomavirus (HPV) infection.

GOAL OF THIS STUDY

To investigate risk factors for HPV detection independent of the correlated risk factors for cervical neoplasia, in a high-risk population.

STUDY DESIGN

We investigated 404 cytologically normal women attending medical assistance clinics in the Washington, D.C. area. Risk factor information was obtained and a cervicovaginal lavage was collected and used for HPV detection and typing by a PCR-based technique.

RESULTS

The point prevalence of HPV was 33.7%. This contrasts with the 17.7% and 44.3% observed in the companion reports published in this issue of the journal. HPV prevalence decreased with age and increased with greater numbers of sexual partners. Moreover, more recent sexual behavior was a better predictor of current HPV detection than lifetime number of sexual partners. Numbers of pregnancies and current pregnancy were positively associated with HPV prevalence and there was an indication that current oral contraceptive users had a higher prevalence of HPV compared to never users. Smoking was not associated with increased HPV prevalence.

CONCLUSION

Findings support the sexual route of transmission of HPV and confirm the association of HPV detection with age, suggesting the host's ability to clear infection or the virus' ability to become latent.

Radiotherapy of malignant subdiaphragmatic implants in advanced ovarian carcinoma: a new technique

We report the development of a new technique using remote afterloading intraoperative radiation therapy to deliver a tumoricidal dose to diaphragmatic tumor implants. A multi-positional lucite applicator was designed based on anatomic studies of the diaphragmatic surface to accommodate a high dose rate iridium source in a series of needles placed 1.5 cm apart. The applicator curvature can vary from planar to full accommodation of the diaphragmatic surface with a constant source to surface distance of 0.5 cm. The applicator has been piloted in three patients with ovarian carcinoma with residual subdiaphragmatic disease found at second look laparotomy, to deliver a dose of 1,500 to 2,000 cGy at 0.5 cm. Tolerance of the diaphragm and hepatic surface has been excellent. There were no postoperative complications and no deterioration in liver function studies. The additional postoperative external beam irradiation directed with the aid of surgically placed clips and gated to respiratory movements permits achievement of a tumoricidal dose while limiting the treated volume and related toxicities.

Reverse hysterocolposigmoidectomy (RHCS) for resection of panpelvic tumors

Lateral retroperitoneal approaches to abdominopelvic masses are commonly employed; the reverse hysterocolposigmoidectomy (RCHS) in addition utilizes transabdominal entry of the vaginal and rectovaginal spaces to provide medial access to the uterosacral and cardinal ligaments as well expose a tumor-free segment of the rectosigmoid for en bloc resection of panpelvic tumors. Thirty-one patients underwent reverse hysterocolpectomy for extensive, symptomatic pelvic malignancies. All patients had complete resection of pelvic tumor, and there were no perioperative deaths. Sigmoid resection was required in 25 patients with 22 primary reanastomosis and 3 end colostomies performed. In 6 patients, vaginal entry facilitated tumor resection while sparing the rectosigmoid. Average operative blood loss was 2677 cc. Early postoperative morbidity (1-30 days) occurred in 13 patients; febrile morbidity (6 patients) was the common complication. Late morbidity (1-6 months) was seen in 10 patients, including 1 fatal pulmonary embolism at 5 months. Subsequent therapy was tolerated well. Mean survival/follow-up is 15.7 months (range, 1 to 49 months). Seventeen patients are alive, seven patients without evidence of disease (average 13.4 months), and ten patients are alive with disease (average follow-up, 28.3 months). Thirteen patients are dead of disease or complication (average survival, 13.7 months). We conclude that RHCS facilitates resection of extensive pelvic tumors with acceptable morbidity.

Manometric characterization of rectal dysfunction following radical hysterectomy

Bladder dysfunction thought to be due to partial denervation has been described following radical hysterectomy. Some patients experience acute and chronic rectal dysfunction characterized by difficulty with defecation and loss of defecatory urge. To define this abnormality, anorectal pressure profiles were examined in 15 patients with Stage I carcinoma of the cervix before and after radical hysterectomy. Profiles were done using standard anorectal manometry with a water-infused system. In all patients preoperative manometric profiles were normal; postoperative studies were abnormal in all patients. Features seen include altered relaxation of the internal sphincter, increased distension needed to trigger relaxation, and decreased rectal sensation; external sphincters and resting internal sphincters were unchanged. Postoperatively, 12 patients reported problems with rectal function. A physiologic defect is definable in patients undergoing radical hysterectomy; this suggests disruption of the spinal reflex arcs controlling rectal emptying. These physiologic abnormalities correlate with the clinical symptomatology experienced by some patients. Continuing definition and evaluation of management options in this situation should be useful in developing effective therapy for rectal dysfunction following radical hysterectomy.

Phase II study of vinblastine in previously treated squamous carcinoma of the cervix. A Gynecologic Oncology Group study

Thirty-six patients with advanced squamous carcinoma of the uterine cervix recurrent after radiotherapy or surgery or first-line chemotherapy were eligible for a phase II study employing vinblastine in a dose of 9 mg/m2 intravenously every 3 weeks until disease progression or toxicity supervened. Two patients were never treated, leaving 34 patients evaluable for toxicity. One patient was inevaluable for response, leaving 33 evaluable for this parameter. Thirty-two patients had prior radiotherapy and 30 had prior chemotherapy. All patients had Gynecologic Oncology Group (GOG) performance status of 0, 1, or 2. Median age was 46 years. Twenty patients had disease in the pelvis and 13 had extrapelvic metastases. Fourteen patients had grade 3 lesions. A median of three courses (range: 1-12 courses) was administered. Ten patients (29.4%) experienced GOG grade 3 or 4 leukocytopenia and 10 had grade 3 or 4 granulocytopenia. Other toxicity included grade 4 gastrointestinal toxicity and anemia in one patient each and two patients with grade 3 neurotoxicity. Twenty patients (60.6%) had stable disease with therapy and 13 had increasing disease. No responses were observed. Vinblastine in this dose and schedule is inactive in previously treated patients with squamous carcinoma of the cervix.

Rapid dysplastic transformation of human genital cells by human papillomavirus type 18

This study delineates differences in biologic activity between human papillomavirus (HPV) types 16 and 18. Human cervical and foreskin epithelial cells were cultured and transfected with recombinant HPV-16 and -18 DNA, resulting in immortalized cell lines. Normal epithelial cells as well as HPV-16 and -18 immortalized cells of both early passages (less than 40 population doublings) and late passages (greater than 180 population doublings) were transplanted in athymic mice. Normal squamous cells formed well-stratified epithelium, while HPV immortalized cells developed either normal-appearing epithelium or typical dysplastic changes. Dysplastic changes were seen in none of the 13 grafts with early-passage HPV-16 cell lines, while 9 of 14 grafts with early-passage HPV-18 cell lines developed dysplasias (P less than 0.0004). These results support previous clinical observations suggesting that HPV-18 may be associated with a more aggressive and rapidly progressive form of cervical neoplasia.

Oral contraceptive use, human papillomavirus infection, and risk of early cytological abnormalities of the cervix

Oral contraceptive (OC) use was examined as a risk factor for cytological abnormalities of the cervix among 1964 women receiving Papanicolaou smears at three hospitals in the Washington, D.C., area. A single pathologist classified cytological results from all women as normal (n = 1423), atypia (n = 314), low grade squamous intraepithelial lesion (SIL; n = 208), or high grade SIL (n = 19). Women in each of the three abnormal groups were compared to women with normal cytological diagnoses. A subset of 579 patients, including most of the women with low or high grade SIL and a matched group of controls, was tested for human papillomavirus (HPV) by type-specific Southern blot hybridization to examine the effects of OC use while taking into account the effects of HPV infection. OC use was found to be unrelated to risk of atypia or low grade SIL but was associated with an elevated risk of high grade SIL that increased with longer duration of use (relative risk = 4.6, 95% confidence interval = 1.1-18.1 for greater than or equal to 5 years of use). HPV infection was associated, as expected, with risk of low and high grade SIL but not with atypia. Taking the HPV results into consideration did not alter the OC findings. There was no evidence that OC use synergistically increased the risk of cervical neoplasia among HPV-infected women, although small numbers prevented a reliable evaluation for high grade SIL. OC use did appear to increase the detection of HPV types 16/18, but the etiological importance of this finding is unclear.

Human cervical and foreskin epithelial cells immortalized by human papillomavirus DNAs exhibit dysplastic differentiation in vivo

Human papillomavirus (HPV) DNAs are detected in approximately 90% of anogenital carcinomas. To assess directly the effect of HPV on squamous differentiation, normal human cervical and foreskin epithelial cells and cells immortalized by recombinant HPV DNAs were transplanted beneath a skin-muscle flap in athymic mice. Xenografts containing normal cells formed well-differentiated stratified squamous epithelia 2 to 3 weeks after transplantation, but cell lines immortalized by four HPV types (HPV16, HPV18, HPV31, and HPV33) detected in anogenital cancer exhibited dysplastic morphology and molecular alterations in gene expression characteristic of intraepithelial neoplasia. Morphological alterations were accompanied by delayed commitment to terminal differentiation, alterations in the pattern of involucrin expression, and reductions in levels of involucrin and keratin 1 RNAs. HPV18-immortalized cells developed dysplastic changes more rapidly than cells immortalized by HPV16 DNA. These results show that human genital epithelial cells immortalized by HPV DNAs detected in genital cancers undergo dysplastic differentiation in vivo.

Clindamycin effect on glycocalyx production in experimental viridans streptococcal endocarditis

Abundant glycocalyx production by viridans streptococci in the rabbit model of endocarditis has been associated with delayed antimicrobial sterilization. Enzymatic digestion of the glycocalyx with dextranase enhances antibiotic activity. The effect of clindamycin (30 mg/kg, subcutaneous, three times daily) was studied in rabbits with experimental aortic valve endocarditis caused by high glycocalyx-producing viridans streptococci. Animals receiving clindamycin had smaller vegetations that were sterilized more quickly than did controls or animals receiving penicillin or dextranase alone (P less than .001). Penicillin plus dextranase treatment allowed greater bacterial killing than penicillin alone and did not differ significantly from clindamycin treatment. Electron micrographs revealed markedly less cell-adherent glycocalyx on organisms grown in vitro treated with clindamycin versus penicillin and controls. It is hypothesized that clindamycin inhibits glycocalyx production in vivo, allowing better antimicrobial penetration in the infected cardiac vegetation.

Expression of the pregnancy-specific beta 1-glycoprotein genes in human testis

Northern blot analysis with placental pregnancy-specific beta 1-glycoprotein (SP1) cDNA probe showed the presence of SP1 mRNAs in human testis. Presence of translational products of the mRNAs was demonstrated by Western blot analysis with anti-human SP1 antibodies albeit difference in mobilities between the testis and placental proteins was apparent. Screening of human testis cDNA library with placental SP1 probe yielded 4 groups of positive clones. Two groups were identical to human placental SP1 cDNAs previously reported. The other 2 groups consisted of cDNA of incompletely processed mRNAs. These 2 groups were present in high abundance. Sequence analysis suggested that the cDNAs were products of different genes.

Characterization of normal human exocervical epithelial cells immortalized in vitro by papillomavirus types 16 and 18 DNA

An in vitro system for studying the interaction between human papillomavirus (HPV) 16 and 18 recombinant DNA and normal human exocervical epithelial cells is described. Eight HPV-immortalized human exocervical epithelial cell lines were established; all the lines contained either integrated HPV16 or 18 sequences and expressed HPV mRNAs. Thus, integration and expression appear to be required for immortalization. Immortalized cells (greater than 200 population doublings to date) divided rapidly (doubling time of 30 to 46 h) and morphologically resembled primary cultures of normal human exocervical epithelial cells. They expressed a keratin pattern consistent with their origin from exocervical epithelium. When cultured at high density or in the presence of serum they terminally differentiated. Sublines resistant to terminal differentiation were selected by growth in serum-supplemented medium. Keratin pattern changes suggest they have some properties in common with cervical squamous carcinoma cells. However, HPV-immortalized cell lines were not tumorgenic in nude mice. Thus, HPV16/18 is not carcinogenic by itself. These cell lines represent an appropriate model for studying factors that regulate HPV gene expression in normal cervical epithelial cells and examining the influence of cocarcinogens on neoplastic progression.

Possible prognostic significance of human papillomavirus type in cervical cancer

While several different human papillomaviruses (HPV) have been associated with cancer of the cervix, it is yet to be determined if specific HPV types have clinical or prognostic significance. To address this question, 30 cases of invasive carcinoma (squamous carcinoma, adenosquamous carcinoma, and adenocarcinoma) with HPV DNA sequences detectable in the tissue were analyzed. HPV type was determined by Southern blot DNA hybridization. Clinical information was obtained by chart review, and all biopsy and surgical specimens were reviewed microscopically without knowledge of HPV type. HPV 16 was detected in 14 cases, HPV 18 in 6, and HPV 31 in 2. In eight samples there were distinctly different, but as yet uncharacterized, HPV DNAs. Of the factors evaluated, tumor grade was found to have a statistically significant relationship to HPV type. Eighty-three percent of HPV 18-associated tumors were grade 3 tumors (5 of 6) as compared to only 7% of HPV 16-associated tumors (1 of 14) (P = 0.002). Age at diagnosis and nodal status in relation to HPV type exhibited a trend but were not statistically significant. The mean age of the HPV 18 group was 37 years, compared to 49 years for the HPV 16 group. Similarly, among Stage IB cancers, nodal involvement was associated with 60% of HPV 18 cases (3 of 5) as compared with 36% of HPV 16 cases (4 of 11). These observations suggest that HPV 18 may be associated with a more aggressive form of cervical cancer than other HPV types.

Diagnostic accuracy of fever as a measure of postoperative pulmonary complications

Various prevalence rates have been estimated for pulmonary complications after abdominal surgery, and fever has been thought to be a diagnostic indicator. This study quantifies the diagnostic accuracy of fever as a measure of postoperative pulmonary complications and includes the sensitivity, specificity, and positive and negative predictive values. Assessments using fever and chest x-ray film were determined for 270 patients after elective intra-abdominal surgery in three hospitals with six practicing surgeons in a Southern Ontario city. With use of reliable chest x-ray reports indicating lung pathologic findings as positive for pulmonary complication, the prevalence of a positive finding was 57%. The prevalence of a fever (temperature greater than or equal to 38 degrees C) was 40%. The sensitivity and negative predictive value of fever were slightly below 50%, and the specificity and positive predictive value of fever was 68% and 66% respectively. Fever was an accurate indicator of x-ray evidence of atelectasis in only 56% of the subjects. Therefore, neither the presence nor the absence of fever can assure clinicians of the presence or absence of a postoperative pathologic pulmonary complication such as atelectasis.

The significance of paraaortic node status in carcinoma of the cervix and endometrium

Survival in 115 women with cervical carcinoma and 55 patients with carcinoma of the endometrium was correlated with the status of paraaortic lymph nodes and the clinical stage of disease. The survival probability at 48 months for patients with cervical cancer who had negative paraaortic lymph nodes was 86% for stage IB in comparison to 67% for those with advanced disease (clinical stages II, III, and IV). The difference of 19% between these two groups was not statistically significant nor was there a statistical difference in survival between early and advanced disease groups when paraaortic nodes contained tumor (37 vs 20%). For all stages of cervical cancer, survival was 80% with negative nodes and 20% with positive nodes at 48 months. In patients with endometrial carcinoma and negative paraaortic lymph nodes, projected survival at 48 months was 72% for stage I and 77% for stages II and III. When paraaortic lymph nodes demonstrated metastatic disease, survival uniformly decreased to 27% of patients with stage I cancer and 25% of those with stage II and III disease. For all stages of endometrial cancer, survival was 76% with negative nodes and 26% with positive nodes at 48 months. The presence or absence of metastatic disease in the paraaortic lymph nodes is an important prognostic factor that appears to be more useful in predicting survival than clinical stage of disease in patients with cervical and endometrial cancer.

Signal sequence of alkaline phosphatase of Escherichia coli

The amino acid sequence of the signal sequence of phoA was determined by DNA sequencing by using the dideoxy chain termination technique (Sanger et al., Proc. Natl. Acad. Sci. U.S.A. 74:5463-5467, 1977). The template used was single-stranded DNA obtained from M13 on f1 phage derivatives carrying phoA, constructed by in vitro recombination. The results confirm the sequence of the first five amino acids determined by Sarthy et al. (J. Bacteriol. 139:932-939, 1979) and extend the sequence in the same reading frame into the amino terminal region of the mature alkaline phosphatase (Bradshaw et al., Proc. Natl. Acad. Sci. U.S.A., 78:3473-3477, 1981). As was predicted (Inouye and Beckwith, Proc. Natl. Acad. Sci. U.S.A. 74:1440-1444, 1977), the signal sequence was highly hydrophobic. The alteration of DNA sequence was identified for a promoter mutation that results in the expression of phoA independent of the positive control gene phoB and in insensitivity to high phosphate.

Antibiotic treatment of parturient women colonized with group B streptococci

A prospective study was conducted among third-trimester parturient women with cervical or urethral colonization with group B streptococci to determine the influence of antibiotic treatment on subsequent colonizations among their infants. Cultures were obtained from dry swabs inoculated directly onto selective blood agar media containing neomycin and naladixic acid. Seventy-four women were found to be colonized among 1,098 cultured (7%). A significant reduction in colonization was noted among mothers treated with ampicillin within three weeks of completion of therapy. This difference was no longer apparent at delivery. There was likewise no difference in the colonization rate of infants in the treatment and no-treatment groups. The data suggest that additional measures must be undertaken to prevent maternal recolonization.