Thoracic growth deficiency in childhood cancer survivors may cause overestimation of lung disease

INTRODUCTION

Survivors of childhood cancers undergo routine pulmonary function testing as they are at an increased lifetime risk for significant lung disease. However, this population also demonstrates growth abnormalities that could influence the interpretation of these tests, as reference equations are based on standing height. We aim to determine the impact of the relative thoracic growth deficiency in childhood cancer survivors on the interpretation of pulmonary function testing.

METHODS

Standing height and upper segment length (USL) in childhood cancer survivors undergoing pulmonary function testing at a single academic center were compared to age-matched historical standards. Additionally, pulmonary function tests were compared to reference values generated from standing height and doubled USL.

RESULTS

Data were obtained from 107 cancer survivors. While the subjects demonstrated an overall 6.8% lower standing height vs historical standards, they also demonstrated relative thoracic growth abnormality with a further 9.9% decrement in the ratio USL to standing height. The use of doubled upper segment length as a surrogate measure for standing height in pulmonary function reference equations decreased the number of patients with restrictive lung disease as indicated by spirometry.

CONCLUSIONS

Childhood cancer survivors have disproportionately worse thoracic growth deficiency vs appendicular growth deficiency. As a result, their USL is disproportionately short for their standing height, which is most commonly used in pulmonary function testing reference equations. This leads to an increased likelihood in these patients meeting pulmonary function test criteria for restrictive lung disease.

Developing a Hospital-Wide Fertility Preservation Service for Pediatric and Young Adult Patients

PURPOSE

Gonadal damage is a common consequence of treatment for pediatric malignancies. Nononcologic conditions may also utilize treatments with potential impact on fertility. Models for oncology fertility preservation programs have emerged and demonstrate that a multidisciplinary team approach can have a positive impact on referral patterns, appropriate risk counseling, and access to fertility preservation options. Expansion of programmatic breadth is needed, providing improved care to nonmalignant conditions where the disease itself may impact reproductive health or treatment modalities.

METHODS

With support from the Department of Pediatrics Chair's Initiative, a multidisciplinary, hospital-wide Fertility Preservation Service was created at the Children's Hospital of Philadelphia. A centralized team provides fertility consults across the institution, allowing for risk-based counseling and facilitation of fertility preservation options (both standard care and experimental).

RESULTS

Team structure, consult process, and available fertility options for prepubertal and pubertal males and females are described. Preinitiative and postinitiative referral patterns were analyzed. Postinitiative referrals from divisions outside oncology more than doubled (34% vs. 15% at baseline).

CONCLUSIONS

A comprehensive model for fertility counseling provides accessible, high-value fertility preservation care to pediatric and young adult patients with a wide variety of diagnoses. A centralized point of contact ensures timely referrals and risk-based counseling and streamlines access to fertility preservation procedures.

Analysis of semen parameters in a young cohort of cancer patients

BACKGROUND

Infertility can be the result of some common cancer treatments and can significantly impact quality of life. Semen cryopreservation allows for fertility preservation. We analyzed the semen parameters of specimens collected from pubertal males from the Children's Hospital of Philadelphia (CHOP) in order to expand current knowledge on the quality of these specimens and inform a standard clinical practice.

PROCEDURE

Males who were at least Tanner stage III and newly diagnosed with cancer at CHOP were approached regarding sperm banking. The success and quality of the samples collected were analyzed and compared in relation to prior treatment, age, and diagnosis.

RESULTS

From 399 patients approached for semen collection, 339 (85%) attempted to bank sperm, of which 265 (78%) were successful and 60 (15%) refused to participate. Therapy prior to sperm banking significantly impacted a successful collection (P < 0.01). Only 16.9% of the untreated patients were azoospermic, whereas 84.0% of the treated subjects were azoospermic. Older patients were less likely to be azoospermic and have a greater quality collection when compared with younger patients (P < 0.01). However, 65% of our youngest patients still were able to cryopreserve semen. There was no difference in azoospermia across diagnostic groups (P = 0.35), though there were differences in quality of semen parameters across diagnoses.

CONCLUSION

Our data support that sperm banking pubertal males prior to the initiation of therapy is feasible. While there were differences in quality of semen parameters across age and diagnostic groups, most males, regardless of age or diagnosis, had adequate specimens for cryopreservation.

Changes in Ocean Heat, Carbon Content, and Ventilation: A Review of the First Decade of GO-SHIP Global Repeat Hydrography

Global ship-based programs, with highly accurate, full water column physical and biogeochemical observations repeated decadally since the 1970s, provide a crucial resource for documenting ocean change. The ocean, a central component of Earth's climate system, is taking up most of Earth's excess anthropogenic heat, with about 19% of this excess in the abyssal ocean beneath 2,000 m, dominated by Southern Ocean warming. The ocean also has taken up about 27% of anthropogenic carbon, resulting in acidification of the upper ocean. Increased stratification has resulted in a decline in oxygen and increase in nutrients in the Northern Hemisphere thermocline and an expansion of tropical oxygen minimum zones. Southern Hemisphere thermocline oxygen increased in the 2000s owing to stronger wind forcing and ventilation. The most recent decade of global hydrography has mapped dissolved organic carbon, a large, bioactive reservoir, for the first time and quantified its contribution to export production (∼20%) and deep-ocean oxygen utilization. Ship-based measurements also show that vertical diffusivity increases from a minimum in the thermocline to a maximum within the bottom 1,500 m, shifting our physical paradigm of the ocean's overturning circulation.

Testicular tissue cryopreservation in prepubertal male children: an analysis of parental decision-making

BACKGROUND

Infertility is an unfortunate treatment-related consequence for some pediatric malignancies as well as some non-malignant conditions treated with stem cell transplant. Unlike pubertal males, prepubertal males cannot produce semen for cryopreservation. This manuscript reports on the acceptability and safety of a multi-institutional protocol for offering testicular tissue cryopreservation to families of prepubertal male children at highest risk for infertility. Data on decision influences, decision-making control, and emotional state when considering this option are described.

PROCEDURE

Prepubertal males facing gonadotoxic therapy were offered testicular cryopreservation. Post-biopsy, patients were followed for acute side effects. In addition, parents and patients were asked to complete questionnaires, whether or not they chose to cryopreserve tissue.

RESULTS

Seventy-four prepubertal male children were approached. Fifty-seven families (77%) consented to the testicular biopsy; 48 of 57 underwent the procedure. There was one post-operative side effect. Parents who agreed to testicular cryopreservation and those that did not felt in control of this decision. Parents who consented to the biopsy and refusers were not deterred by the experimental nature of the protocol. An important decision-making influence was the risk of the biopsy.

CONCLUSION

Biopsy and cryopreservation of testicular tissue from prepubertal male children was performed successfully and safely at three institutions. Parents faced with this option at diagnosis can make an informed decision and weigh carefully the risks and benefits. Although asked to make a decision soon after they were given a difficult diagnosis, parents uniformly felt in control of this decision.

Prevalence of advanced bone age in a cohort of patients who received cis-retinoic acid for high-risk neuroblastoma

In the last decade, 13-cis-retinoic acid (13-cis-RA) has been added to the treatment of patients with high-risk neuroblastoma. In survivors of neuroblastoma, short stature is consistently observed. Causes include growth hormone deficiency and poor growth of irradiated long bones. Within the survivorship program at CHOP, we have observed that a number of these patients also have advanced bone ages. Children treated with 13-cis-RA are at risk for advanced bone age that may dramatically impact their linear growth. Ongoing evaluation is necessary to examine the effect of 13-cis-RA on final adult height and to inform clinical practice in this cohort.

An experimental protocol for fertility preservation in prepubertal boys recently diagnosed with cancer: a report of acceptability and safety

BACKGROUND

Gonadal damage is a consequence of therapy for pediatric malignancies. Prepubertal males have no semen or mature spermatozoa, posing a challenge for fertility preservation. Testicular tissue cryopreservation is a potential option but is still experimental. We report on a pilot protocol that offered testicular biopsy cryopreservation to families of prepubertal boys with newly diagnosed malignancy. The aims were to determine the acceptability and safety of this procedure.

METHODS

Parents of prepubertal boys with diagnoses at highest risk for treatment-related gonadal damage were offered the option of testicular cryopreservation. Half of the biopsy was frozen for the subject's potential future use and the remainder used for research. Data on negative intraoperative and/or 7 day post-operative sequelae of testicular biopsies were assessed. Two to four weeks later, parents were asked to complete a questionnaire on factors influencing their decision to have the biopsy or not.

RESULTS

Since January 2008, 24 boys have met the eligibility criteria but three required immediate treatment and were excluded. Sixteen of 21 families (76%) consented to testicular biopsy, indicating the prospective acceptability of this option to parents of boys aged 3 months to 14 years; 14 underwent the procedure without any negative intra- or post-operative sequelae. Although the time at diagnosis is stressful, families can give thoughtful consideration to this option. Factors such as religion, finance, ethics and the experimental nature of cryopreservation did not play a major role in decision-making.

CONCLUSIONS

Parents of prepubertal boys with cancer are willing to pursue testicular tissue cryopreservation at diagnosis, and testicular biopsy caused no acute adverse effects.

Late effects in survivors of tandem peripheral blood stem cell transplant for high-risk neuroblastoma

BACKGROUND

Increasing numbers of children with advanced neuroblastoma are achieving cure. We describe the clinical late effects specific to survivors of stage IV neuroblastoma all similarly treated using tandem autologous peripheral blood stem cell rescue with TBI.

METHOD

The medical records of 35 neuroblastoma patients treated at CHOP between 1997 and 2001 were examined. Eighteen of the 35 patients died of progressive disease, and 4 were lost to follow-up. Thirteen patients continue to follow-up in our Multidisciplinary Cancer Survivorship Clinic where they are evaluated and monitored by a consistent group of subspecialists that evaluate long-term sequelae. Data on treatment exposures including TBI and treatment related sequelae identified by clinician assessment and/or diagnostic testing were collected.

RESULTS

Results indicate late effects were present in all 13 subjects, 12 of whom suffered from multiple negative sequelae, including issues with growth hormone deficiency, dental problems, osteochondromas and hearing deficiencies, among others, most at higher rates than reported previously.

CONCLUSIONS

The findings in this small cohort indicate the need for future prospective studies of this intensive pediatric cancer treatment, and underscore the importance of medical intervention and long-term monitoring of these at-risk subjects to increase overall quality-of-life.

Sperm banking for adolescent and young adult cancer patients: sperm quality, patient, and parent perspectives

BACKGROUND

Infertility is often a complication for adolescent and young adult males who receive cancer therapy, a problem that might be averted through using cryopreserved sperm. We aim to evaluate feasibility of offering newly diagnosed patients the opportunity to bank sperm and, to determine the beliefs and decision-making processes of patients and their parents who considered sperm banking.

PROCEDURE

Eligible patients and parents were approached and offered sperm cryopreservation. Semen samples from patients who sequentially attempted sperm banking were analyzed. Questionnaires were then administered to patients and parents who had been approached about sperm banking.

RESULTS

Semen samples from 68 patients were analyzed. Nine patients were azoospermic; all had been pre-treated with chemotherapy. Fifty patients completed the questionnaire. Parent and patient made the decision together to bank 80% of the time. All sons who attempted to bank and their parents felt they had made the right decision, including those who attempted but failed.

CONCLUSIONS

Viable sperm can be collected successfully from adolescent and young adults who are newly diagnosed with cancer. Semen quality was dramatically reduced by one course of gonadotoxic therapy. Parents and patients want information regarding sperm cryopreservation early. Parents appear to play an important role in the decision to sperm bank. We recommend sperm banking be offered to all eligible patients.

Sperm Banking for Adolescents With Cancer

Recent advances in diagnostic and therapeutic methods in pediatric oncology have led to greater survival rates in children with malignancies. However, major long-term complications can occur that limit the quality of survival, infertility being one of them. Chemotherapy, radiation treatment, surgery, and combinations of these treatments have been implicated in causing infertility, with males being especially sensitive to therapy. Cryopreservation of semen, or sperm banking, is an easy, widely available means to preserve fertility for adolescent and young adult males with cancer. In this article, the pertinent literature is reviewed, and a sperm-banking program is described. Recommendations are offered for institutions attempting to develop a successful program, and the nurse's role in education and facilitation is discussed.

A Multidisciplinary Model of Care for Childhood Cancer Survivors With Complex Medical Needs

Long-term survival for children with cancer is often achieved at a considerable cost in terms of medical and psychological sequelae. Although many survivors are well and require only routine follow-up and surveillance, a cohort of survivors require comprehensive management of complex, chronic medical issues by multiple subspecialists. For these survivors, care delivered within the context of an annual visit to a traditional hospital—based late effects clinic or by a primary care physician in the community is often not adequate. A specialized clinic was implemented at The Children's Hospital of Philadelphia that crosses disciplines and provides same-day, same-clinic access to oncology/survivorship, endocrinology, pulmonology, cardiology, nutrition, and psychology. This multidisciplinary approach supports clinical efficiency and fosters seamless patient-centered care both for patients with identified late effects and for those with the highest risk for problems because of intense treatment exposures. The model is described with a focus on clinic structure/process, clinical outcomes, and benefits to survivor, health care provider, and institution. The diverse roles for nursing within this model are highlighted.

A comparative analysis of functional outcomes in adolescents and young adults with lower-extremity bone sarcoma

BACKGROUND

Comparison of functional mobility and quality of life is performed in patients with lower-extremity bone sarcoma following either amputation, limb-sparing surgery, or rotationplasty with four different types of outcome measures: (1) an objective functional mobility measure that requires patients to physically perform specific tasks, functional mobility assessment (FMA); (2) a clinician administered tool, Musculoskeletal Tumor Society Scale (MSTS); (3) a patient questionnaire, Toronto Extremity Salvage Scale (TESS); and (4) a health-related quality of life (HRQL) measure, Short Form-36 version 2 (SF-36v.2).

PROCEDURE

This is a prospective multi-site study including 91 patients with lower-extremity bone sarcoma following amputation, limb-sparing surgery, or rotationplasty. One of three physical therapists administered the quality of life measure (SF-36v.2) as well as a battery of functional measures (FMA, MSTS, and TESS).

RESULTS

Differences between patients who had amputation, limb-sparing surgery, or rotationplasty were consistently demonstrated by the FMA. Patients with limb sparing femur surgery performed better than those patients with an above the knee amputation but similarly to a small number of rotationplasty patients. Several of the more conventional self-report measures were shown to not have the discriminative capabilities of the FMA in these cohorts.

CONCLUSION

In adolescents with lower-extremity bone sarcoma, it may be advantageous to consider the use of a combination of outcome measures, including the FMA, for objective functional mobility assessment along with the TESS for a subjective measure of disability and the SF-36v.2 for a quality-of-life measure.

Assessing functional mobility in survivors of lower-extremity sarcoma: reliability and validity of a new assessment tool

BACKGROUND

Reliability and validity of a new tool, Functional Mobility Assessment (FMA), were examined in patients with lower-extremity sarcoma. FMA requires the patients to physically perform the functional mobility measures, unlike patient self-report or clinician administered measures.

PROCEDURE

A sample of 114 subjects participated, 20 healthy volunteers and 94 patients with lower-extremity sarcoma after amputation, limb-sparing, or rotationplasty surgery. Reliability of the FMA was examined by three raters testing 20 healthy volunteers and 23 subjects with lower-extremity sarcoma. Concurrent validity was examined using data from 94 subjects with lower-extremity sarcoma who completed the FMA, Musculoskeletal Tumor Society (MSTS), Short-Form 36 (SF-36v2), and Toronto Extremity Salvage Scale (TESS) scores. Construct validity was measured by the ability of the FMA to discriminate between subjects with and without functional mobility deficits.

RESULTS

FMA demonstrated excellent reliability (ICC [2,1] >or=0.97). Moderate correlations were found between FMA and SF-36v2 (r = 0.60, P < 0.01), FMA and MSTS (r = 0.68, P < 0.01), and FMA and TESS (r = 0.62, P < 0.01). The patients with lower-extremity sarcoma scored lower on the FMA as compared to healthy controls (P < 0.01).

CONCLUSION

The FMA is a reliable and valid functional outcome measure for patients with lower-extremity sarcoma. This study supports the ability of the FMA to discriminate between patients with varying functional abilities and supports the need to include measures of objective functional mobility in examination of patients with lower-extremity sarcoma.

Pulmonary function abnormalities in children treated with whole lung irradiation

BACKGROUND

We sought to determine the prevalence of abnormal pulmonary function tests (PFTs) in a cohort of children who had received whole lung irradiation (WLI) for treatment of metastatic disease.

PROCEDURE

This was a retrospective (1988-2003) chart review that included all children treated at our institution with WLI who had undergone PFT. Data abstracted included oncologic diagnosis, radiation dose and fractionation, spirometry (FVC, FEV1, FEV1/FVC, FEF25%-75%), plethysmography (TLC, FRC, RV, RV/TLC), diffusing capacity (DLCO), and respiratory muscle strength (MIP, MEP). PFTs were normalized according to standard deviation (Z) scores.

RESULTS

Thirty patients were identified who had one or more PFT. The incidence of mild, moderate, or severe reductions in FEV1 was 30%, 10%, and 10%, respectively, with 50% having normal FEV1. Seventeen percent of patients had mild reduction in total lung capacity (TLC), while 13% and 30% had moderate or severe reductions. Thirty-eight percent had mild reductions in diffusing capacity, while 29% and 14% had moderate or severe reductions.

CONCLUSIONS

Pulmonary function abnormalities were common in this cohort of children treated with WLI, and may be progressive in nature. Further studies are warranted to identify patients at highest risk.

Delivering long-term follow-up care to pediatric cancer survivors: transitional care issues

One of the major challenges faced by young adult survivors of childhood cancer is the transition from a specialized pediatric care facility to adult-based health care that provides appropriate follow-up. This review summarizes the issues regarding the necessity of this transition, including a brief history of follow-up care of childhood cancer survivors. The general principles of transition care, as well as the barriers and obstacles specific to this population are outlined with the advantages and limitations of several models of transition care that could be considered.

Relationships among range of motion, functional mobility, and quality of life in children and adolescents after limb-sparing surgery for lower-extremity sarcoma

PURPOSE

The study was designed to examine relationships between range of motion (ROM), functional mobility, and quality of life (QL) in patients with lower-extremity sarcoma (LES) after limb-sparing surgery

METHODS

Sixty-eight patients with LES (age, 10-26 years) participated. The patients performed hip flexion, hip extension, knee flexion, and knee extension, Timed Up and Down Stairs (TUDS), Timed Up and Go (TUG), nine-minute run-walk (9-min), and completed the QL measure, Short-Form-36 version two (SF-36v2).

RESULTS

Significant correlations (p < 0.01) were found between hip extension and SF-36v2 physical component scale (PCS; r = 0.33), TUDS (r = -0.32), TUG (r = -0.33); hip flexion and TUDS (r = -0.31), TUG (r = -0.39), 9-min (r = 0.44); knee flexion and TUDS (r = -0.52), TUG (r = -0.40), 9-min (r = 0.37); SF-36v2 PCS and TUDS (r = -0.56), TUG (r = -0.51), 9-min (r = 0.60).

CONCLUSION

ROM correlates with functional mobility and QL in patients with LES after limb-sparing surgery. ROM exercises are important component of a physical therapy program for children and adolescents with LES.

Fertility in males treated for Hodgkins disease with COPP/ABV hybrid

More than 80% of those diagnosed with Hodgkins disease (HD) will survive long-term. For the past decade, a modified hybrid consisting of cyclophosphamide (2.4-3.6g/m(2)), vincristine, procarbazine, and prednisone (COPP) together with adriamycin, bleomycin, and vinblastine (ABV) has been used to treat patients with HD. Little data exists on how this modified hybrid impacts male fertility. Eleven male patients treated with COPP-ABV hybrid were studied. Nine out of 11 subjects were categorized as infertile by semen analysis; 7 of 9 were azoospermic. There was no association between fertility status and prepubertal status at diagnosis or gonadotropin status. Despite lower doses of cyclophosphamide, treatment with the current COPP/ABV hybrid leads to infertility in the majority of young men. It is likely that procarbazine, an effective yet potent gonadotoxic agent, is responsible for this outcome.

Human papilloma virus E6 and E7 proteins support DNA replication of adenoviruses deleted for the E1A and E1B genes

The action of transforming proteins from small DNA tumor viruses seems to be remarkably similar between different viruses, as they all use pRb and p53 pathways as cellular targets. This leads to deregulation of host cell cycling, which in turn creates an environment favorable for viral replication. Based on this, we hypothesized that regulatory proteins from human papillomaviruses (HPVs) can functionally trans-complement viral DNA replication of adenoviruses deleted for the E1A and E1B genes (AdE1-). To test this, we constructed AdE1- vectors expressing the human papilloma virus 16 (HPV-16) proteins E6 and E7. Expression of both E6 and E7 from these vectors partially complemented adenoviral DNA replication activity in vitro, in SK-Hep1 cells and primary human astrocytes, as well as in vivo in mouse liver. AdE1- vectors expressing E6 and E7 also increased hepatocellular DNA synthesis in vivo. Efficient AdE1- DNA replication was detected in HPV-associated cervical carcinoma cells but not in primary human cells. Linking the expression of regulatory oncoviral proteins to DNA replication of E1-mutant adenoviruses may provide a rationale for antitumor strategies.

Tumor-specific gene expression in hepatic metastases by a replication-activated adenovirus vector

Clinical applications of tumor gene therapy require tumor-specific delivery or expression of therapeutic genes in order to maximize the oncolytic index and minimize side effects. This study demonstrates activation of transgene expression exclusively in hepatic metastases after systemic application of a modified first-generation (E1A/E1B-deleted) adenovirus vector (AdE1-) in mouse tumor models. The discrimination between tumors and normal liver tissue is based on selective DNA replication of AdE1- vectors in tumor cells. This new AdE1- based vector system uses homologous recombination between inverted repeats to mediate precise rearrangements within the viral genome. As a result of these rearrangements, a promoter is brought into conjunction with a reporter gene creating a functional expression cassette. Genomic rearrangements are dependent upon viral DNA replication, which in turn occurs specifically in tumor cells. In a mouse tumor model with liver metastases derived from human tumor cells, a single systemic administration of replication activated AdE1- vectors achieved transgene expression in every metastasis, whereas no extra-tumoral transgene induction was observed. Here we provide a new concept for tumor-specific gene expression that is also applicable for other conditionally replicating adenovirus vectors.

Bacterial chromosomal painting for in situ monitoring of cultured marine bacteria

We previously described a new method, bacterial chromosomal painting (BCP), for the in situ identification of bacterial cells. Here, we describe the application of this technique to study the ecology and physiology of cultured marine pelagic bacteria from the western Sargasso Sea (WSS). A total of 86 bacteria were isolated from seawater collected from near the surface, at a depth of 250 m and from nutrient-amended seawater incubations. The 10 bacterial isolates that were best represented in environmental genomic DNA from the WSS were selected using reverse genome probing. BCP hybridization cell counts were used to determine the depth-specific distribution of one of the alpha proteobacterial isolates, B5-6, in the WSS during two thermal stratification regimes: stratified and partially mixed. The maximum cell count measured for B5-6 at the summer deep chlorophyll maximum was approximately 4% of the total cell count. This study is the first application of BCP to natural environments.

Lack of RB protein correlates with increased sensitivity to UV-radiation-induced apoptosis in human breast cancer cells

The underlying causes for different apoptotic responses in neoplastic cells are still not fully understood. We demonstrate here that a human breast cancer cell line, MDA-MB-468, which lacks the retinoblastoma protein (RB), is particularly sensitive to low doses of ultraviolet (UV) radiation. These cells are 15-20-fold more sensitive to UV radiation than RB-positive cell lines, as measured by both apoptosis and clonogenic assays. In addition, a prostate cancer cell line that lacks functional RB, DU-145, was found to have a similar apoptotic response to low doses of UV radiation. Based on these data, we hypothesized that the lack of RB is responsible for the extreme sensitivity of these cells to UV-radiation-induced apoptosis. To further examine the role of RB in apoptosis, cells of RB-positive human breast cancer and normal cell lines were infected with the human papilloma virus type 16 (HPV-16) E7 and assessed for UV-radiation sensitivity. The HPV-16 E7 protein is known to decrease levels of free RB in cells. Infection of RB-positive human breast cancer or normal cells with E7 resulted in a 4-5-fold increase in sensitivity to UV radiation compared to controls. The above data suggest a role for the RB protein in protecting cells from undergoing apoptosis in response to UV radiation.

DNA replication of first-generation adenovirus vectors in tumor cells

A major role of the early gene 1A and 1B products (E1A and E1B) in adenovirus infection is to create a cellular environment appropriate for viral DNA replication. This is, in part, achieved by inactivation of tumor suppressor gene products such as pRb or p53. The functions of these same cellular proteins are also frequently lost in tumor cells. Therefore, we hypothesized that tumor cell lines with deregulated p53 and/or pRb pathways might support replication of E1A/E1B-deleted, first-generation adenovirus vectors (AdE1(-)). Here, we analyzed the impact of virus uptake, cell cycling, and the status of cell cycle regulators on AdE1(-) DNA synthesis. Cellular internalization of AdE1(-) vectors varied significantly among different tumor cell lines, whereas nuclear import of incoming viral DNA appeared to be less variable. Replication assays performed under equalized infection conditions demonstrated that all analyzed tumor cell lines supported AdE1(-) synthesis to varying degrees. There was no obvious correlation between the efficiency of viral DNA replication and the status of p53, pRb, and p16. However, the amount of virus attached and internalized changed with the cell cycle, affecting the intracellular concentration of viral DNA and thereby the replication efficacy. Furthermore, infection with AdE1 - vectors caused a partial G(2)/M arrest or delay in cell cycle progression, which became more pronounced in consecutive cell cycles. Correspondingly, vector DNA replication was found to be enhanced in cells artificially arrested in G(2)/M. Our findings suggest that cell cycling and thus passing through G(2)/M supports AdE1(-) DNA replication in the absence of E1A/E1B. This has potential implications for the use of first-generation adenovirus vectors in tumor gene therapy.

Comparison of four clinical specimen types for detection of influenza A and B viruses by optical immunoassay (FLU OIA test) and cell culture methods

Although laboratory diagnosis of respiratory viruses has been widely studied, there is a relative insufficiency of literature examining the impact of specimen type on the laboratory diagnosis of influenza A and B. In a clinical study comparing the FLU OIA test with 14-day cell culture, clinical specimens from nasopharyngeal swabs, throat swabs, nasal aspirates, and sputum were obtained from patients experiencing influenza-like symptoms. A total of 404 clinical specimens were collected from 184 patients. Patients were defined as influenza positive if the viral culture of a specimen from any sample site was positive. Patients were defined as influenza negative if the viral cultures of specimens from all sample sites were negative. By this gold standard, culture and FLU OIA test results for each sample type were compared. For each of the four specimen types, the viral culture and FLU OIA test demonstrated equal abilities to detect the presence of influenza A or B virus or viral antigen. Sputum and nasal aspirate samples were the most predictive of influenza virus infection. Throat swabs were the least predictive of influenza virus infection, with both tests failing to detect influenza virus in nearly 50% of the throat samples studied.

Integrating adenovirus-adeno-associated virus hybrid vectors devoid of all viral genes

Recently, we demonstrated that inverted repeat sequences inserted into first-generation adenovirus (Ad) vector genomes mediate precise genomic rearrangements resulting in vector genomes devoid of all viral genes that are efficiently packaged into functional Ad capsids. As a specific application of this finding, we generated adenovirus-adeno-associated virus (AAV) hybrid vectors, first-generation Ad vectors containing AAV inverted terminal repeat sequences (ITRs) flanking a reporter gene cassette inserted into the E1 region. We hypothesized that the AAV ITRs present within the hybrid vector genome could mediate the formation of rearranged vector genomes (DeltaAd.AAV) and stimulate transgene integration. We demonstrate here that DeltaAd.AAV vectors are efficiently generated as by-products of first-generation adenovirus-AAV vector amplification. DeltaAd.AAV genomes contain only the transgene flanked by AAV ITRs, Ad packaging signals, and Ad ITRs. DeltaAd.AAV vectors can be produced at a high titer and purity. In vitro transduction properties of these deleted hybrid vectors were evaluated in direct comparison with first-generation Ad and recombinant AAV vectors (rAAVs). The DeltaAd.AAV hybrid vector stably transduced cultured cells with efficiencies comparable to rAAV. Since cells transduced with DeltaAd.AAV did not express cytotoxic viral proteins, hybrid viruses could be applied at very high multiplicities of infection to increase transduction rates. Southern analysis and pulsed-field gel electrophoresis suggested that DeltaAd.AAV integrated randomly as head-to-tail tandems into the host cell genome. The presence of two intact AAV ITRs was crucial for the production of hybrid vectors and for transgene integration. DeltaAd.AAV vectors, which are straightforward in their production, represent a promising tool for stable gene transfer in vitro and in vivo.

Generation of adenovirus vectors devoid of all viral genes by recombination between inverted repeats

Direct or inverse repeated sequences are important functional features of prokaryotic and eukaryotic genomes. Considering the unique mechanism, involving single-stranded genomic intermediates, by which adenovirus (Ad) replicates its genome, we investigated whether repetitive homologous sequences inserted into E1-deleted adenoviral vectors would affect replication of viral DNA. In these studies we found that inverted repeats (IRs) inserted into the E1 region could mediate predictable genomic rearrangements, resulting in vector genomes devoid of all viral genes. These genomes (termed DeltaAd.IR) contained only the transgene cassette flanked on both sides by precisely duplicated IRs, Ad packaging signals, and Ad inverted terminal repeat sequences. Generation of DeltaAd.IR genomes could also be achieved by coinfecting two viruses, each providing one inverse homology element. The formation of DeltaAd.IR genomes required Ad DNA replication and appeared to involve recombination between the homologous inverted sequences. The formation of DeltaAd. IR genomes did not depend on the sequence within or adjacent to the inverted repeat elements. The small DeltaAd.IR vector genomes were efficiently packaged into functional Ad particles. All functions for DeltaAd.IR replication and packaging were provided by the full-length genome amplified in the same cell. DeltaAd.IR vectors were produced at a yield of approximately 10(4) particles per cell, which could be separated from virions with full-length genomes based on their lighter buoyant density. DeltaAd.IR vectors infected cultured cells with the same efficiency as first-generation vectors; however, transgene expression was only transient due to the instability of deleted genomes within transduced cells. The finding that IRs present within Ad vector genomes can mediate precise genetic rearrangements has important implications for the development of new vectors for gene therapy approaches.

Microsurgical treatment of lumbar disc herniation: follow-up of 237 patients

We have reviewed retrospectively the results of 237 consecutive patients who underwent microsurgical discectomy for a virgin lumbar disc herniation. Included were 128 (54%) mean and 109 (46%) women, with the mean age of 42 years. Intra-operatively, protrusion was found in 60 (25%) patients, prolapse in 127 (54%) patients and sequestration in 50 (21%) patients. The median post-operative follow-up time was 2 years. During the observation period, sciatic pain had completely recovered or markedly diminished in 218 (92%) patients, and 187 (79%) patients had returned to work. The mean duration of preoperative sciatica was 3.8 months in those patients who finally returned to work. In contrast, it was as long as 6.3 months in those patients who lost their working capacity as a consequence of low back pain. The patients operated on for a prolapse or a sequestrum recovered better than those who underwent surgery for a protrusion. Of the patients operated on for a protrusion, 68% returned to work, while 76% of those operated on for a sequestrum and 85% of those operated on for a prolapse returned to work during the follow-up. Difference was seen also in the occupational outcome: only 37% of the patients operated on for a protrusion reported to manage their work well, while 47% of those with a prolapse and 58% of those with a sequestrum managed well. Surgical complications were infrequent in this study. Dural tear appeared in 10 (4%) patients and post-operative discitis in 4 (1.7%) patients. Of all patients, 9 (4%) required re-operation for a true recurrent disc.

Allergic reactions to latex among health-care workers

With the emergence of the acquired immunodeficiency syndrome (AIDS) epidemic and the practice of protecting health-care workers from all body fluids, the use of rubber gloves has increased, as has occupational allergy to latex among health-care workers. During 1991, 49 Mayo Medical Center employees sought assessment and treatment of rhinitis, conjunctivitis, contact urticaria, contact dermatitis, asthma, or eczema thought to be related to exposure to latex. Most of these persons had a history of atopy and worked in areas where rubber gloves were used and changed frequently. Of the 49 subjects, 34 had positive results of skin tests to latex products, and the sera from 19 of 35 persons tested contained increased latex-specific IgE antibodies. Employees with sensitivity to latex (and co-workers in the immediate areas) should use vinyl gloves and should notify their own health-care providers of their sensitization. Changes in job assignment may be necessary for some persons.

Antihypertensive effects of a new sustained-release formulation of nifedipine

The blood pressure response to a new sustained-release formulation of nifedipine was evaluated in an 8-week, double-blind, placebo-controlled study. Twenty-nine patients with mild essential hypertension were randomized to receive placebo (N = 9), 30 mg nifedipine (N = 10), or 60 mg nifedipine (N = 10). During treatment, 30-mg and 60-mg doses of nifedipine administered once daily decreased office blood pressures from 137/98 +/- 8/2 mm Hg and 141/98 +/- 15/2 mm Hg at baseline, respectively, to 126/89 +/- 9/7 mm Hg and 126/86 +/- 6/7 mm Hg (P less than .005). Noninvasive automatic ambulatory blood pressure monitoring demonstrated a marginally significant (P less than .10) reduction in the mean 24-hour blood pressure of 2/6 +/- 8/8 mm Hg and 5/6 +/- 9/9 mm Hg for patients taking 30 mg and 60 mg nifedipine once daily, respectively. Diastolic blood pressure load (the percentage of ambulatory diastolic blood pressure readings greater than 90 mm Hg) during 24 hours was decreased by 41% and 35%, with 30 mg and 60 mg nifedipine administered once daily, respectively. No significant dose response to nifedipine at these dose levels was observed. Although the once-daily formulation of nifedipine achieved effective control of office blood pressure, similar control was not observed in awake and 24-hour periods in all patients.

Immune activation is associated with phenylhydrazine-induced anemia in the rat

Long-term phenylhydrazine (PHZ) treatment caused pronounced anemia and a concomitant increase in the numbers of circulating leukocytes in Long-Evans rats. The leukocytosis was caused mainly by an elevation in mononuclear cells, most notably in the lymphocyte population. PHZ has been reported to cause the direct lysis of erythrocytes by nonimmune mechanisms. However, recent reports indicate that PHZ can cross-link red cell band 3 protein (senescent antigen), resulting in the binding of autologous immunoglobulin G (IgG). Recognition of this complex by macrophage Fc receptor mechanisms triggers rapid erythrophagocytosis-in the spleen and possibly the liver as well. In our study, analysis of the blood, bone marrow, and spleen cells of long-term (1 to 6 weeks) PHZ-treated rats was performed by using flow cytometry. Total serum IgG levels were determined by radial immunodiffusion, and antibodies reactive with red cells that were sensitized to PHZ either in vivo or in vitro were titered by using the indirect Coombs' method. Serum prostaglandin E2 titers also were determined at different time intervals after PHZ administration. The results indicate that PHZ induces an increase in circulating antibody and prostaglandin E2 titers that correlates with the onset of anemia and that the serum of PHZ-treated rats can induce anemia in normal recipients after passive transfer. Cytofluorographic studies revealed a marked increase in the B-cell population of the peripheral blood and spleen and an altered ratio T-helper to T-suppressor cells at certain time intervals after PHZ injection. The results indicate that in addition to inducing senescence-like alterations in erythrocyte membrane proteins, PHZ stimulates the production of the autologous IgG that recognizes these sites and promotes lymphoid blastogenesis, most notably in the B-cell lineage.

Blood pressure load--a better determinant of hypertension

Noninvasive ambulatory blood pressure monitoring was used to evaluate the diagnosis of hypertension in 168 untreated patients with essential hypertension. On the basis of overall office blood pressure--the mean of 12 measurements, 2 in each of three positions (supine, sitting, and standing) on 2 consecutive days--133 patients were diagnosed as having hypertension (diastolic blood pressure of 90 mm Hg or higher) and 35 as having borderline hypertension (diastolic blood pressure of less than 90 mm Hg). The mean blood pressures for those with hypertension and borderline hypertension were 149/99 and 135/87 mm Hg, respectively. The mean ambulatory diastolic blood pressure was 90 mm Hg or higher in 123 patients during awake hours and in 91 patients during 24 hours. The diastolic blood pressure loads (percentage of ambulatory diastolic blood pressures more than 90 mm Hg) in patients with hypertension and borderline hypertension, respectively, were 69% and 43% during awake hours and 59% and 35% during 24 hours. The systolic blood pressure loads (percentage of systolic readings more than 140 mm Hg) during awake and 24 hours were 56% and 48%, respectively, in patients with established hypertension and 31% and 26%, respectively, in those with borderline hypertension. Thus, ambulatory blood pressure monitoring and blood pressure load provide useful information for diagnosing hypertension.

Correlation between verapamil plasma concentration and P-R prolongation in essential hypertension

Plasma verapamil concentration was correlated with serial electrocardiographic P-R intervals in patients with essential hypertension receiving immediate-release (80 to 120 mg three times a day) or sustained-release (240 mg daily) verapamil. The mean P-R interval in 22 patients taking placebo and immediate-release verapamil was 0.18 second. The borderline first-degree atrioventricular block of three patients did not change during treatment. Plasma verapamil concentrations of patients with a P-R interval longer than 0.20 second and of those with a P-R interval of 0.20 second or less were 169 +/- 73 ng/mL and 63 +/- 8 ng/mL, respectively. Six patients taking sustained-release verapamil had a maximal mean P-R interval of 0.19 +/- 0.01 second during 24-hour ambulatory electrocardiographic monitoring. P-R intervals were 0.22 second or more in two patients, but they returned to normal by hour 7 for one and by hour 20 for the other patient. In summary, transient P-R prolongation occurred with oral verapamil therapy, but no patient, regardless of baseline P-R interval, developed high-grade atrioventricular block.

Antihypertensive efficacy of lisinopril. Ambulatory blood pressure monitoring

Noninvasive automatic ambulatory blood pressure monitoring during 24 hours in eight patients with moderate hypertension was used to determine the blood pressure response to lisinopril, an angiotensin-converting enzyme inhibitor. Office, 24-hour ambulatory, awake ambulatory, and sleep ambulatory diastolic blood pressures were decreased from 108 +/- 3, 98 +/- 8, 101 +/- 7, and 87 +/- 14 mm Hg, respectively, at baseline to 83 +/- 4 (P less than or equal to 0.0001), 82 +/- 7 (P less than 0.0001), 84 +/- 7 (P less than 0.0001), and 73 +/- 9 mm Hg (P less than 0.005), respectively, after 20 weeks of lisinopril treatment (dose range, 40 to 80 mg once daily). The diastolic blood pressure loads (percentages of ambulatory diastolic blood pressures more than 90 mm Hg) during 24 hours and during awake hours were 74% +/- 19% and 83% +/- 15%, respectively, at baseline and 24% +/- 19% (P less than 0.0001) and 29% +/- 21% (P less than 0.0001), respectively, during treatment. Heart rate was not altered by lisinopril. In conclusion, lisinopril is an effective antihypertensive agent for the treatment of moderate hypertension, and ambulatory blood pressures and diastolic blood pressure loads are useful for evaluating therapy for hypertension.

The biology of natural transformation

Natural transformation is widely distributed among bacteria. Its variations, in terms of specific mechanisms, may in part reflect responses to different selective pressures in different bacteria. We have suggested that both gene transfer and acquisition of carbon, nitrogen, and energy represent physiological needs that may have contributed to the evolution of natural transformation. While natural transformation was the first mechanism of genetic exchange to be detected, it is perhaps the least understood. Our understanding of the mechanism for uptake and incorporation of soluble DNA has increased significantly in the last two decades, but the overall picture of transformation as a biologically significant function is still unfolding. The mechanism by which DNA is released for transformation, the control of genes involved in DNA release and uptake, the potential for transformation in the natural environment, and the potential of natural transformation as a tool for other microbiological studies are but a few of the important issues that remain.

Inability of Pseudomonas stutzeri denitrification mutants with the phenotype of Pseudomonas aeruginosa to grow in nitrous oxide

Pseudomonas aeruginosa PAO1 reduced nitrous oxide to dinitrogen but did not grow anaerobically in nitrous oxide. Two transposon insertion Nos- mutants of Pseudomonas stutzeri exhibited the P. aeruginosa phenotype. Growth yield studies demonstrated that nitrous oxide produced in vivo was productively respired, but nitrous oxide supplied exogenously was not. The defect may be in electron transport or in nitrous oxide uptake.

Thymidine salvage in Pseudomonas stutzeri and Pseudomonas aeruginosa provided by heterologous expression of Escherichia coli thymidine kinase gene

Unlike enteric bacteria, Pseudomonas spp. generally lack thymidine phosphorylase and thymidine kinase activities, thus preventing their utilization of exogenous thymine or thymidine and precluding specific radioactive labeling of their DNA in vivo. To overcome this limitation, a DNA fragment encoding thymidine kinase (EC 2.7.1.21) from Escherichia coli was cloned into pKT230, a small, broad-host-range plasmid derived from plasmid RSF1010. From transformed E. coli colonies, the recombinant plasmid bearing the thymidine kinase gene was conjugally transferred to Pseudomonas stutzeri, Pseudomonas aeruginosa, Pseudomonas mendocina, Pseudomonas alcaligenes, and Pseudomonas pseudoalcaligenes. Thymidine kinase activity was expressed in all of these species, and all gained the ability to incorporate exogenous [2-14C]thymidine into their DNA. Thymidine incorporation into P. stutzeri was enhanced 12-fold more in mutants lacking thymidylate synthetase activity. These mutants produced higher levels of thymidine kinase and were thymidine auxotrophs; thymineless death resulted from removal of thymidine from a growing culture.

Evidence for an active role of donor cells in natural transformation of Pseudomonas stutzeri

The transfer of chromosomal genes in a cell mat of Pseudomonas stutzeri was ca. 10(3) times more efficient per microgram of DNA if DNA was added as a constituent of intact donor cells rather than as a solution. Such intact cell-mediated transfer appears to depend on cell contact. It is independent of the presence of plasmids in donor strains and is DNase I sensitive, thus fitting the usual definition of transformation. It is bidirectional: cells of either strain in a transformation mixture served as the donor and recipients. The donor function in cell contact transformation was inhibited by nalidixic acid but was unaffected by rifampin and streptomycin at growth-inhibiting concentrations. Concentrations of nalidixic acid sufficient to inhibit donor function completely had no effect on the ability of nalidixic acid-resistant recipients to take up DNA from solution. These experiments suggest that certain cells donate DNA to others in the cell mat: they argue against the hypothesis that the function of donor cells is merely cell lysis.

Comparison of denitrification by Pseudomonas stutzeri, Pseudomonas aeruginosa, and Paracoccus denitrificans

A comparison was made of denitrification by Pseudomonas stutzeri, Pseudomonas aeruginosa, and Paracoccus denitrificans. Although all three organisms reduced nitrate to dinitrogen gas, they did so at different rates and accumulated different kinds and amounts of intermediates. Their rates of anaerobic growth on nitrate varied about 1.5-fold; concomitant gas production varied more than 8-fold. Cell yields from nitrate varied threefold. Rates of gas production by resting cells incubated with nitrate, nitrite, or nitrous oxide varied 2-, 6-, and 15-fold, respectively, among the three species. The composition of the gas produced also varied markedly: Pseudomonas stutzeri produced only dinitrogen; Pseudomonas aeruginosa and Paracoccus denitrificans produced nitrous oxide as well; and under certain conditions Pseudomonas aeruginosa produced even more nitrous oxide than dinitrogen. Pseudomonas stutzeri and Paracoccus denitrificans rapidly reduced nitrate, nitrite, and nitrous oxide and were able to grow anaerobically when any of these nitrogen oxides were present in the medium. Pseudomonas aeruginosa reduced these oxides slowly and was unable to grow anaerobically at the expense of nitrous oxide. Furthermore, nitric and nitrous oxide reduction by Pseudomonas aeruginosa were exceptionally sensitive to inhibition by nitrite. Thus, although it has been well studied physiologically and genetically, Pseudomonas aeruginosa may not be the best species for studying the later steps of the denitrification pathway.

The physiological genetics of denitrifying bacteria

The genetics of denitrification is a relatively unexplored area that has great promise. Species of Pseudomonas are probably best suited for study because they are widely found among natural denitrifying populations and are quite readily amenable to genetic analysis. The techniques for mutagenesis and for the exchange of chromosomal genes to characterize mutant strains have been well-developed in P. aeruginosa and are being developed in P. stutzeri. Mutants defective in the denitrification of nitrate, nitrite, and nitrous oxide are now available and will aid in describing the catalytic and regulatory elements of the denitrification pathway.

Pseudomonas stutzeri and related species undergo natural transformation

Cells of Pseudomonas stutzeri are naturally transformed by homologous chromosomal DNA; they do not require chemical treatment to become competent. This capacity to undergo natural transformation was found to be shared by the closely related species P. mendocina, P. alcaligenes, and P. pseudoalcaligenes, but was not detectable in strains of P. aeruginosa, P. perfectomarinus, P. putida, P. fluorescens, or P. syringae. P. stutzeri could be transformed either on plates or in liquid medium. Only double-stranded chromosomal DNA was effective; single-stranded DNA and plasmid DNA were not. DNA fragments larger than 10 kilobase pairs were more effective than smaller fragments. The transformation frequency was proportional to DNA concentration from 1 ng/ml to 1 microgram/ml; higher concentrations were saturating. The maximum frequency, about 10(-4) transformants per recipient cell, was obtained with cells from a culture in the early stationary growth phase. A variety of chromosomal mutations have been transformed, including mutations to auxotrophy and to antibiotic resistance. Other systems for genetic exchange in P. stutzeri have not yet been found; transformation offers a means for the genetic analysis of this metabolically versatile organism.

Properties of dissimilatory nitrate reductase purified from the denitrifier Pseudomonas aeruginosa

Dissimilatory nitrate reductase was purified to homogeneity from anaerobic cultures of the denitrifying bacterium Pseudomonas aeruginosa. The following procedures were used in the rapid isolation of this unstable enzyme: induction by nitrate in semianaerobic cell suspension, heat-stimulated activation and solubilization from the membrane fraction, and purification by hydrophobic interaction chromatography. The molecular weight of the purified enzyme was estimated by nondenaturing polyacrylamide gel electrophoresis, sucrose density gradient sedimentation, and gel filtration chromatography. Subunit molecular weights were estimated by electrophoresis in sodium dodecyl sulfate-polyacrylamide gels. The active enzyme monomer, with a molecular weight of 176,000 to 260,000 (depending upon the method of determination), was composed of subunits with molecular weights of approximately 64,000 and 118,000. The monomer aggregated to form an inactive tetramer of about 800,000 molecular weight. Purified enzyme exhibited a broad pH optimum, between 6.5 and 7.5. Kinetic studies showed that the apparent Km was 0.30 mM for nitrate, and 2.2 to 2.9 microM for dithionite-reduced benzyl viologen. Azide was an effective inhibitor: the concentration required for half-maximal inhibition was 21 to 24 microM. Azide inhibition was competitive with nitrate (Ki = 2.0 microM) but uncompetitive with reduced benzyl viologen (Ki = 25 microM). Based upon spectral evidence, the purified molybdo-enzyme had no associated cytochromes but did contain nonhaem iron that responded to dithionite reduction and nitrate oxidation. The enzyme that was purified after being heat solubilized from membranes had properties essentially identical to those of the enzyme that was purified after deoxycholate solubilization.

Involvement of arginine residues in the allosteric activation of Escherichia coli ADP-glucose synthetase

Inactivation of Escherichia coli ADP-glucose synthetase (EC 2.7.2.27) by the arginine-specific reagents cyclohexanedione and phenylglyoxal resulted primarily from interference with normal allosteric activation. Partial modification by phenylglyoxal resulted in a lessened ability of fructose 1,6-bisphosphate (fructose-P2) to stimulate and of 5'-AMP (5'-adenylate) to inhibit enzymic activity. The apparent affinity for fructose-P2 and the Vmax at saturating fructose-P2 concentrations were decreased by the arginine modification. Fructose-P2, 5'-adenylate, and several other allosteric effectors were able to partially protect the enzyme from inactivation. However, catalytic activity was not decreased by arginine modification under conditions where the enzyme was assayed in the absence of fructose-P2. The two arginine-modifying reagents differed markedly in their reactivity with the enzyme. Cyclohexanedione inactivated the enzyme quite slowly and eventually reacted with at least 14 of the 32 arginines present per subunit. Phenylglyoxal was some 50-fold more effective in inactivation, but it modified only one arginine residue per subunit.

Modification of the allosteric activator site of Escherichia coli ADP-glucose synthetase by trinitrobenzenesulfonate

Limited modification of Escherichia coli B ADP-glucose synthetase (EC 2.7.7.27) by trinitrobenzenesulfonate (TNBS) appeared to affect primarily the allosteric properties of the enzyme. There was little loss of the catalytic activity assayed in the absence of activator. However, the abilities of fructose 1,6-bisphosphate or hexanediol 1,6-bisphosphate to activate the enzyme, or of 5'-adenylate to inhibit the enzyme, were rapidly lost upon trinitrophenylation. Modification progressively decreased the affinity for activator, decreased the Vmax at saturating concentrations of activator, and decreased the cooperativity among activator binding sites. These effects could be completely prevented by the presence of allosteric effectors during reaction with TNBS, although a low amount of trinitrophenylation still occurred. Substrates partially protected the enzyme from reaction with TNBS. The lysyl epsilon-amino side chain was modified by trinitrophenylation, but the target was not primarily the same residue which could form a Schiff base with pyridoxal phosphate, another activator of the enzyme. A large peptide containing most of the trinitrophenyl residue was isolated after cleavage of the enzyme and was identified as part of the N-terminal amino acid sequence. The migration of the enzyme on polyacrylamide gel electrophoresis or on agarose column chromatography was unchanged by modification. However, the ability of fructose-1, 6-P2 to induce the oligomerization of a mutant form of the enzyme was completely prevented by trinitrophenylation. This effect could be protected against by the presence of activator or inhibitor during reaction with TNBS.

Is the vasospasm following subarachnoidal hemorrhage an immunoreactive disease?

Subarachnoidal hemorrhage (SAH) from an arterial aneurysm is often followed by vasospasm which may lead to severe or even fatal ischemic brain lesions. The cause of the vasospasm is still unknown. In the present study it is shown that patients with SAH and roentgenological and/or clinical vasospasm have a significantly higher frequency (52%) of circulating immune complexes in the blood than patients with SAH without spasm (9%). This finding indicates that the vasospasm following SAH may be elicited via an immunoreaction.

The use of immunocytochemical techniques for the detection of steroid hormones in breast cancer cells

Indirect immunofluorescence and immunoperoxidase assays were developed to detect estradiol and progesterone in breast cancer cells. Appropriate controls were used to confirm immunologic specificity. Studies of estradiol binding by human breast cancer cells identified three groups: no detectable binding (25%); all tumor cells exhibiting binding although to different degrees (4%); and tumors with varying numbers of positive and negative cells (71%). Similar observations were made with respect to progesterone binding. The percentage of cells with estradiol binding was correlated with the amount of estrogen receptors (ER) present in the tumor specimens. Post-hormone binding events e.g., nuclear binding of estradiol, were also evaluated. Some tumor cells showing cytoplasmic binding of estradiol did not show nuclear binding of estradiol; such tumors lacked detectable diethylstilbestrol under routine assay conditions, and relatively high concentrations of estradiol were needed to observe estradiol-specific staining. The results suggest that the immunocytochemical assays detect hormone-specific binding, but that the binding is probably due to multiple classes of steroid-binding sites.

Biosynthesis of bacterial glycogen. Activator-induced oligomerization of a mutant Escherichia coli ADP-glucose synthase

ADP-glucose synthase (EC 2.7.7.27) was purified to homogeneity from SG5-504, Aa mutant strain of Escherichia coli B. It had a molecular weight of approximately 2 X 10(5) and four identical subunits. In the presence of its allosteric activator, fructose-1-6-P2, the mutant enzyme formed oligomers with several times the tetramer molecular weight, as revealed by sedimentation equilibrium centrifugation, polyacrylamide gel electrophoresis, and gel filtration column chromatography. Enzyme purified from a wild type strain, AC70R1, did not exhibit the activator-induced oligomerization. Catalytically, the mutant enzyme had a 2-fold higher affinity for activator and a 2- to 3-fold lower affinity for the allosteric inhibitors 5'-adenylate and KH2PO4 than the wild type. The two enzymes appeared identical in subunit molecular weight, amino acid composition, COOH-terminal amino acid, and the first 27 residues of the NH2-terminal sequence. Subtle structural differences were revealed by chemical modification of specific residues. Compared to wild type, the mutant enzyme had 1 cysteine/subunit more accessible to modification by Ellman's reagent. SG5-504 enzyme was inactivated more slowly than AC70R1 enzyme by phenylglyoxal and by trinitrobenzenesulfonate. These results reflected an altered conformation of the SG5-504 enzyme molecule. The unique ability of it to oligomerize in the presence of activator may be the result of a single amino acid substitution.