Lupus erythematosus-specific bullous lesions

Lupus erythematosus (LE)-specific bullous lesions are often difficult to distinguish from other bullous diseases presenting in patients with systemic lupus erythematosus. Herein, we describe a 49-year-old woman with systemic lupus erythematosus with recurrent tense bullae on the forearms. Clinical, histopathologic, and serologic findings led to the diagnosis of LE-specific bullous lesions. We also summarize the diagnostic clues for distinguishing LE-specific bullous lesions, bullous systemic lupus erythematosus, and erythema multiforme-like lesions in LE (Rowell syndrome).

Pediatric pyoderma gangrenosum associated with leukocyte adhesion deficiency type 1: A case report and review of the literature

Pyoderma gangrenosum is a rare neutrophilic dermatosis characterized by painful skin ulcers with necrotic, undermined margins. In severe cases, particularly in pediatric patients, work-up for an associated autoimmune, inflammatory, malignant, or genetic disorder should be considered based on the clinical presentation. We report a unique case of pediatric pyoderma gangrenosum with a leukemoid reaction, secondary to an autosomal recessive leukocyte adhesion deficiency type 1.

Intermittent Hypoxia Differentially Regulates Adenosine Receptors in Phrenic Motor Neurons with Spinal Cord Injury

Cervical spinal cord injury (cSCI) impairs neural drive to the respiratory muscles, causing life- threatening complications such as respiratory insufficiency and diminished airway protection. Repetitive "low dose" acute intermittent hypoxia (AIH) is a promising strategy to restore motor function in people with chronic SCI. Conversely, "high dose" chronic intermittent hypoxia (CIH; ∼8 h/night), such as experienced during sleep apnea, causes pathology. Sleep apnea, spinal ischemia, hypoxia and neuroinflammation associated with cSCI increase extracellular adenosine concentrations and activate spinal adenosine receptors which in turn constrains the functional benefits of therapeutic AIH. Adenosine 1 and 2A receptors (A₁, A_2A) compete to determine net cAMP signaling and likely the tAIH efficacy with chronic cSCI. Since cSCI and intermittent hypoxia may regulate adenosine receptor expression in phrenic motor neurons, we tested the hypotheses that: 1) daily AIH (28 days) downregulates A_2A and upregulates A₁ receptor expression; 2) CIH (28 days) upregulates A_2A and downregulates A₁ receptor expression; and 3) cSCI alters the impact of CIH on adenosine receptor expression. Daily AIH had no effect on either adenosine receptor in intact or injured rats. However, CIH exerted complex effects depending on injury status. Whereas CIH increased A₁ receptor expression in intact (not injured) rats, it increased A_2A receptor expression in spinally injured (not intact) rats. The differential impact of CIH reinforces the concept that the injured spinal cord behaves in distinct ways from intact spinal cords, and that these differences should be considered in the design of experiments and/or new treatments for chronic cSCI.

Impact of Skin Biopsy and Clinical-Pathologic Correlation in Dermatology Inpatient Consults

Background

While studies of hospital dermatology have demonstrated diagnostic discordance between primary teams and dermatology consultants, little is known about the impact of biopsy and clinical-pathologic correlation (CPC) in consultation. This study compares biopsy performance based on diagnostic discordance and evaluates the impact of CPC on the diagnosis.

Methods

This was a retrospective review of 376 dermatologic consultations at a single academic medical center between July 1, 2017, and June 27, 2018.

Results

Biopsy was significantly less likely to be performed when the diagnosis by the referring primary team was unspecified (p < 0.001). In 24 percent of cases, the diagnosis based on histopathology alone differed from the diagnosis reached by formal CPC consensus review with either potential or significant impact on management.

Conclusion

Dermatologists who perform inpatient consultations and rely on hospital-based pathology services may consider a consensus review for CPC. Requests to perform a biopsy may be interpreted as a request for diagnostic assistance rather than pressure to perform a procedure.

Attitudes and practices about fertility preservation discussions among young adults with cancer treated at a comprehensive cancer center: patient and oncologist perspectives

BACKGROUND

Young adults (YAs, ages 18-39) diagnosed with cancer face multiple challenges that affect their health-related quality of life, including the potential for cancer-related infertility. Providing information about the risk of infertility and options to maintain fertility is critical for YAs who are newly diagnosed. However, barriers to effective communication exist for oncologists and their patients. The purpose of this study was to interview medical oncologists and YAs from the same cancer center to examine attitudes and practices about fertility preservation.

METHODS

Semi-structured interviews were conducted with medical oncologists (N=12) and YAs within 2 years post-treatment (N=24), representing the most common cancers affecting YAs. Interviews were audio-recorded, transcribed, and coded using qualitative methodologies with the analysis software NVivo 10.

RESULTS

Twelve oncologists (50% female, 67% <50 years) and 24 YAs (67% female, M=29 years) completed interviews. Common themes across oncologist and YA interviews were the roles of cancer type or stage and patient interest or parity in influencing the decision. The most important factor for YAs was to receive accurate, in-depth information. Unique themes for oncologists focused on clinical aspects of their patient's disease. For YAs, they shared about the emotional impact of cancer-related infertility and desire for support from trusted others.

CONCLUSIONS

Results provide a better understanding of the attitudes and practices about fertility preservation discussions among YAs. Given the common factors affecting fertility preservation decisions, models of shared decision-making may be ideal for YAs and oncologists. Future interventions should explore tailored applications of this approach for YAs newly diagnosed with cancer.

Serotonergic innervation of respiratory motor nuclei after cervical spinal injury: Impact of intermittent hypoxia

Although cervical spinal cord injury (cSCI) disrupts bulbo-spinal serotonergic projections, partial recovery of spinal serotonergic innervation below the injury site is observed after incomplete cSCI. Since serotonin contributes to functional recovery post-injury, treatments to restore or accelerate serotonergic reinnervation are of considerable interest. Intermittent hypoxia (IH) was reported to increase serotonin innervation near respiratory motor neurons in spinal intact rats, and to improve function after cSCI. Here, we tested the hypotheses that spontaneous serotonergic reinnervation of key respiratory (phrenic and intercostal) motor nuclei: 1) is partially restored 12 weeks post C2 hemisection (C2Hx); 2) is enhanced by IH; and 3) results from sprouting of spared crossed-spinal serotonergic projections below the site of injury. Serotonin was assessed via immunofluorescence in male Sprague Dawley rats with and without C2Hx (12 wks post-injury); individual groups were exposed to 28 days of: 1) normoxia; 2) daily acute IH (dAIH28: 10, 5 min 10.5% O2 episodes per day; 5 min normoxic intervals); 3) mild chronic IH (IH28-5/5: 5 min 10.5% O2 episodes; 5 min intervals; 8 h/day); or 4) moderate chronic IH (IH28-2/2: 2 min 10.5% O2 episodes; 2 min intervals; 8 h/day), simulating IH experienced during moderate sleep apnea. After C2Hx, the number of ipsilateral serotonergic structures was decreased in both motor nuclei, regardless of IH protocol. However, serotonergic structures were larger after C2Hx in both motor nuclei, and total serotonin immunolabeling area was increased in the phrenic motor nucleus but reduced in the intercostal motor nucleus. Both chronic IH protocols increased serotonin structure size and total area in the phrenic motor nuclei of uninjured rats, but had no detectable effects after C2Hx. Although the functional implications of fewer but larger serotonergic structures are unclear, we confirm that serotonergic reinnervation is substantial following injury, but IH does not affect the extent of reinnervation.

Ovarian Stimulation Is Safe and Effective for Patients with Gynecologic Cancer

Purpose: To compare long-term outcomes of gynecologic cancer patients who pursued controlled ovarian hyperstimulation (COH) for fertility preservation (FP) with those who did not. Methods: Retrospective cohort, COH, and health outcomes in gynecologic cancer patients; data were analyzed by chi-square test, t-tests, and logistic regression. Results: Ninety patients with a gynecologic malignancy contacted the FP patient navigator: 45.6% (n = 41) had ovarian cancer, 25.6% (n = 23) endometrial cancer, 18.9% (n = 17) cervical cancer, 5.6% (n = 5) uterine cancer, and 4.4% (n = 4) multiple gynecologic cancers. From this cohort, 32 underwent COH, 43 did not, and 18 pursued ovarian tissue cryopreservation (OTC; 3 patients had both COH and OTC). Median age and type of cancer were not significantly different between the groups. COH patients had a range of 1-35 oocytes retrieved. Days to next cancer treatment in the COH group was 36 days; for those who declined COH, it was 22 days (not significant [NS], p > 0.05). There were two recurrences reported in the stimulation group and four in the no stimulation group (NS). Five deaths were reported, two in the stimulation group, none in the no stimulation group, and three in the OTC group (NS); 34% (n = 11) COH patients returned to use cryopreserved specimens, of which 45% (n = 5) had a live birth. Conclusion: Although time to next treatment was longer in the group of patients who underwent COH, this did not reach statistical significance. It appears that in selected patients with GYN malignancies, COH for oocyte or embryo cryopreservation is safe, with reasonable stimulation outcomes and no difference in long-term outcomes.

Pathologic features of response to neoadjuvant anti-PD-1 in resected non-small-cell lung carcinoma: a proposal for quantitative immune-related pathologic response criteria (irPRC)

Background

Neoadjuvant anti-PD-1 may improve outcomes for patients with resectable NSCLC and provides a critical window for examining pathologic features associated with response. Resections showing major pathologic response to neoadjuvant therapy, defined as ≤10% residual viable tumor (RVT), may predict improved long-term patient outcome. However, %RVT calculations were developed in the context of chemotherapy (%cRVT). An immune-related %RVT (%irRVT) has yet to be developed.

Patients and methods

The first trial of neoadjuvant anti-PD-1 (nivolumab, NCT02259621) was just reported. We analyzed hematoxylin and eosin-stained slides from the post-treatment resection specimens of the 20 patients with non-small-cell lung carcinoma who underwent definitive surgery. Pretreatment tumor biopsies and preresection radiographic 'tumor' measurements were also assessed.

Results

We found that the regression bed (the area of immune-mediated tumor clearance) accounts for the previously noted discrepancy between CT imaging and pathologic assessment of residual tumor. The regression bed is characterized by (i) immune activation-dense tumor infiltrating lymphocytes with macrophages and tertiary lymphoid structures; (ii) massive tumor cell death-cholesterol clefts; and (iii) tissue repair-neovascularization and proliferative fibrosis (each feature enriched in major pathologic responders versus nonresponders, P < 0.05). This distinct constellation of histologic findings was not identified in any pretreatment specimens. Histopathologic features of the regression bed were used to develop 'Immune-Related Pathologic Response Criteria' (irPRC), and these criteria were shown to be reproducible amongst pathologists. Specifically, %irRVT had improved interobserver consistency compared with %cRVT [median per-case %RVT variability 5% (0%-29%) versus 10% (0%-58%), P = 0.007] and a twofold decrease in median standard deviation across pathologists within a sample (4.6 versus 2.2, P = 0.002).

Conclusions

irPRC may be used to standardize pathologic assessment of immunotherapeutic efficacy. Long-term follow-up is needed to determine irPRC reliability as a surrogate for recurrence-free and overall survival.

Ovarian stimulation is a safe and effective fertility preservation option in the adolescent and young adult population

PURPOSE

The aim of this study is to describe the multidisciplinary approach and controlled ovarian hyperstimulation (COH) outcomes in adolescent and young adult (AYA) patients (ages 13-21) who underwent oocyte cryopreservation for fertility preservation (FP).

METHODS

Multi-site retrospective cohort was performed from 2007 to 2018 at Northwestern University and Michigan University. Data were analyzed by chi-square test, t-test, and logistic regression.

RESULTS

Forty-one patients began COH of which 38 patients successfully underwent oocyte retrieval, with mature oocytes obtained and cryopreserved without any adverse outcomes. To treat this group of patients, we use a multidisciplinary approach with a patient navigator. When dividing patients by ages 13-17 vs. 18-21, the median doses of FSH used were 2325 and 2038 IU, the median number of mature oocytes retrieved were 10 and 10, and median number frozen oocytes were 11 and 13, respectively. Median days of stimulation were 10 for both groups. There was no statistical difference in BMI, AMH, peak E₂, FSH dosage, days stimulated, total oocytes retrieved, mature oocytes retrieved, and oocytes frozen between the two groups. Three patients were canceled for poor response.

CONCLUSION

COH with oocyte cryopreservation is a feasible FP option for AYAs who may not have other alternatives when appropriate precautions are taken, such as proper counseling and having a support team. These promising outcomes correspond to similar findings of recent small case series, providing hope for these patients to have genetically related offspring in the future.

Analysis of natural product regulation of cannabinoid receptors in the treatment of human disease

The organized, tightly regulated signaling relays engaged by the cannabinoid receptors (CBs) and their ligands, G proteins and other effectors, together constitute the endocannabinoid system (ECS). This system governs many biological functions including cell proliferation, regulation of ion transport and neuronal messaging. This review will firstly examine the physiology of the ECS, briefly discussing some anomalies in the relay of the ECS signaling as these are consequently linked to maladies of global concern including neurological disorders, cardiovascular disease and cancer. While endogenous ligands are crucial for dispatching messages through the ECS, there are also commonalities in binding affinities with copious exogenous ligands, both natural and synthetic. Therefore, this review provides a comparative analysis of both types of exogenous ligands with emphasis on natural products given their putative safer efficacy and the role of Δ9-tetrahydrocannabinol (Δ9-THC) in uncovering the ECS. Efficacy is congruent to both types of compounds but noteworthy is the effect of a combination therapy to achieve efficacy without unideal side-effects. An example is Sativex that displayed promise in treating Huntington's disease (HD) in preclinical models allowing for its transition to current clinical investigation. Despite the in vitro and preclinical efficacy of Δ9-THC to treat neurodegenerative ailments, its psychotropic effects limit its clinical applicability to treating feeding disorders. We therefore propose further investigation of other compounds and their combinations such as the triterpene, α,β-amyrin that exhibited greater binding affinity to CB₁ than CB₂ and was more potent than Δ9-THC and the N-alkylamides that exhibited CB₂ selective affinity; the latter can be explored towards peripherally exclusive ECS modulation. The synthetic CB₁ antagonist, Rimonabant was pulled from commercial markets for the treatment of diabetes, however its analogue SR144528 maybe an ideal lead molecule towards this end and HU-210 and Org27569 are also promising synthetic small molecules.

Disparities in Counseling Female Cancer Patients for Fertility Preservation

BACKGROUND

Female cancer patients who are exposed to gonadotoxic chemotherapy are at risk of future infertility. Research suggests that disparities in fertility preservation counseling (FPC) may exist. Previous research is limited by recall bias; therefore, this study examined objective electronic medical chart data regarding FPC at an academic medical center.

MATERIALS AND METHODS

This study included reproductive-aged women (18-45 years old) with a diagnosis of breast, gynecological, or hematological cancer and who were exposed to a gonadotoxic chemotherapeutic agent from 2009 to 2013. Chi-square and logistic regression analyses were utilized to analyze disparities in FPC.

RESULTS

Two hundred fifty-nine women met the study criteria. One hundred eighty-one women were diagnosed with breast cancer, 52 with hematological cancer, and 26 with gynecological cancer. 160/259 (62%) women had documented counseling for fertility preservation (FP), 60 (23%) women were not counseled as counseling was determined to be "not applicable," 16 (6%) women were not counseled and no explanation was given for the lack of counseling, and counseling was not documented in 23 (9%) charts. Age, marital status, and racial/ethnic background were related to counseling status. Patients with gynecological or hematological cancer were more likely to be counseled than other patients. Logistic regression results demonstrated that FPC was largely driven by cancer diagnosis.

CONCLUSIONS

Although cancer diagnosis was the greatest predictor of FPC, disparities were evident in the counseling of female cancer patients for FP treatment. Equality in counseling female patients for FP treatment is imperative to reduce the risk of emotional harm and future infertility.

Documentation of Fertility Preservation Discussions for Young Adults With Cancer: Examining Compliance With Treatment Guidelines

BACKGROUND

Professional guidelines have been developed to promote discussion between providers and newly diagnosed young adults with cancer about the possibility of cancer treatment-related infertility, but previous research suggests many young adults fail to receive this information. The aim of this study was to examine rates of and factors predictive of oncologists' compliance with national guidelines for discussing potential treatment-related infertility with newly diagnosed young adults with cancer seen at an NCI-designated comprehensive cancer center.

METHODS

We reviewed data from the electronic medical record for new clinic encounters between medical oncologists and young adults with cancer (ages 18-39 years) from 2010 to 2012. Data from oncologist discussions of fertility preservation were abstracted, as were patient (age, sex, race, ethnicity, cancer type) and oncologist (gender, graduation year from fellowship) characteristics.

RESULTS

A total of 1,018 cases were reviewed, with 454 patients (mean, 31.5 years; 67.8% women) meeting inclusion criteria. Overall, 83% of patients were informed about potential treatment-related infertility, with patients with breast cancer (85% informed), Hodgkin lymphoma (95% informed), non-Hodgkin's lymphoma (94% informed), leukemia (88% informed), or testicular cancer (100% informed) more likely to be informed than those with other cancer types (60%-74% informed). There was a significant effect for patient sex (odds ratio, 3.57; CI, 1.33, 9.60; P=.012), with women being more likely to be informed than men.

CONCLUSIONS

Reported compliance with fertility preservation guidelines was greater than published rates. Higher compliance rates in female patients and in patients with cancers more common among young adults may reflect greater awareness of fertility-related concerns among these patients and their providers.

Psychological Counseling of Female Fertility Preservation Patients

Young cancer patients are increasingly interested in preserving their fertility prior to undergoing gonadotoxic therapies. Although the medical safety and treatment protocols for fertility preservation have been well documented, limited research has addressed the emotional issues that arise in fertility preservation patients. We briefly review the literature on the psychosocial issues in adult female fertility preservation treatment and describe our experiences within this patient population. Our findings suggest that several important issues to be addressed during the psychological counseling of adult female fertility preservation patients include: (1) preexisting psychological distress in patients undergoing treatment, (2) choice of fertility preservation strategy in the face of an uncertain relationship future, (3) decision making regarding use of third-party reproduction (e.g., sperm/egg donation, gestational surrogacy), (4) treatment expectations regarding pregnancy and miscarriage, (5) ethical issues related to treatment including the creation, cryopreservation, and disposition of embryos/oocytes, and (6) decision regret from patients who declined fertility preservation.

Prospective study of depression and anxiety in female fertility preservation and infertility patients

OBJECTIVE

To prospectively assess anxiety, depression, coping, and appraisal in female fertility preservation (FP) patients compared with infertile patients.

DESIGN

Prospective pre- and post-treatment survey.

SETTING

Academic medical center.

PATIENT(S)

Forty-seven women with cancer (FP patients) and 91 age-matched infertile patients.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Depression, anxiety, coping, infertility-related stress, appraisal of treatment, and medical outcomes.

RESULT(S)

FP patients reported more symptoms of anxiety and depression than infertile patients, but infertile patients' symptoms worsened over time; 44% of FP and 14% of infertile patients' scores exceeded the clinical cutoff for depression before treatment. The interval between surveys and medical treatment data did not predict changes in mood symptoms. Coping strategies and infertility-related stress did not differ between groups, and avoidant coping predicted higher depression and anxiety scores.

CONCLUSION(S)

FP patients reported more anxiety and depression than infertile patients at enrollment in treatment, with more than one-third of FP patients reporting clinically significant depressive symptoms. However, infertile patients' anxiety and depressive symptoms increased across treatment. This increase was not related to time between registration for IVF and oocyte retrieval or the medical aspects of treatment. FP and infertile patients should be provided psychologic consultation before treatment to identify mood and anxiety symptoms and to refer patients for counseling as needed to prevent worsening of symptoms.

Square Pegs, Round Hole? Ensuring Fit in the AYAO Spectrum for Adolescents and Young Adults with Genetic Risk for Cancer

This paper presents a case example of a young woman at genetic risk for future cancer. We discuss psychosocial challenges that adolescents and young adults (AYAs) may share with their cancer survivor peers, and describe an example of psychosocial care. A scientific foundation denoting the needs of AYAs at risk for heritable cancers is lacking, and it is unknown if these AYAs receive adequate support services. This is a call to action for practitioners and researchers to engage in initiatives that assure these AYAs have access to valuable support and more clearly mark their place within the spectrum of AYA oncology.

Mitogenomic and microsatellite variation in descendants of the founder population of Newfoundland: high genetic diversity in an historically isolated population

The island of Newfoundland, the first of England's overseas colonies, was settled from the 17th century onward by restricted numbers of English, Irish, and French immigrants, in small "outport" communities that have maintained geographic, religious, and linguistic isolation to the latest generations. To measure the extent of modification and loss of genetic variation through founder effect, drift, and inbreeding in this historically isolated population, we analyzed the complete mitochondrial DNA (mtDNA) genomes and 14 microsatellite loci from each of 27 individuals with matrilineal ancestries extending to the colonial period. Every individual has a unique mtDNA genome sequence. All but one of these genomes are assignable to one of five major (H,J,K,T, and U) or minor (I) European haplogroups. The possibility of homoplasy at single nucleotide polymorphism (SNP) sites that define subtypes within the H haplogroup is discussed. Observed haplogroup proportions do not differ significantly from those of western Europeans or between English and Irish Newfoundlanders. The exceptional individual is a member of haplogroup A2, who appears to be the descendant of a Mi'kmaq First Nations mother and a French father, a common marriage pattern in the early settlement of Newfoundland. Microsatellite diversity is high (HE = 0.763), unstructured with respect to mtDNA haplotype or ethnicity, and there is no evidence of linkage disequilibrium. There is a small but significant degree of inbreeding (FIS = 0.0174). Collection of whole mtDNA genome data was facilitated by the use of microarray sequencing, and we describe a simple algorithm that is 99.67% efficient for sequence recovery.

Pyruvate kinase deficiency as a cause of extreme hyperbilirubinemia in neonates from a polygamist community

Neonatal hemolytic jaundice is a risk factor for kernicterus. Pyruvate kinase (PK) deficiency is a rare cause of neonatal hemolytic jaundice, with a prevalence estimated at 1 case per 20,000 births in the United States, but with a higher prevalence among the Amish communities in Pennsylvania and Ohio. We discovered four neonates with PK deficiency born in a small community of polygamists. All four had early, severe, hemolytic jaundice. PK deficiency should be considered in neonates with early hemolytic, Coombs-negative, non-spherocytic jaundice, particularly in communities with considerable consanguinity. Such cases should be recognized early and managed aggressively to prevent kernicterus.

Spinal 2-chloroprocaine: a dose-ranging study and the effect of added epinephrine

With the availability of preservative- and antioxidant-free 2-chloroprocaine (2-CP), there may be an acceptable short-acting alternative to lidocaine for spinal anesthesia. We examined the safety, dose-response characteristics, and effects of epinephrine with spinal 2-CP. Six volunteers per group were randomized to receive 30, 45, or 60 mg of spinal 2-CP with and without epinephrine. Intensity and duration of sensory and motor blockade were assessed. When 11 of the 18 volunteers complained of vague, nonspecific flu-like symptoms, breaking of the blind revealed that all spinal anesthetics associated with the flu-like symptoms contained epinephrine. There were no complaints of flu-like symptoms in the volunteers who received 2-CP without epinephrine. No further spinal anesthetics containing epinephrine were administered, resulting in 29 anesthetics (11 with epinephrine, 18 without epinephrine.) Plain 2-CP demonstrated a dose-dependent increase in peak block height and duration of effect at all variables except time to 2-segment regression and time to regression to T10. Time to complete sensory regression with plain 2-CP was 98 +/- 20, 116 +/- 15, and 132 +/- 23 min, respectively. 2-CP with epinephrine produced times to complete sensory regression of 153 +/- 25, 162 +/- 33, and 148 +/- 29 min, respectively. Preservative and antioxidant free 2-CP can be used effectively for spinal anesthesia in doses of 30-60 mg. Epinephrine is not recommended as an adjunct because of the frequent incidence of side effects.

IMPLICATIONS

Hyperbaric spinal 2-chloroprocaine is effective and has an anesthetic profile appropriate for use in the surgical outpatient over the dose range of 30-60 mg without signs of transient neurologic symptoms. The addition of epinephrine is not recommended because of the frequent incidence of side effects.

B-type cyclins CLB5 and CLB6 control the initiation of recombination and synaptonemal complex formation in yeast meiosis

BACKGROUND

The life cycle of most eukaryotic organisms includes a meiotic phase, in which diploid parental cells produce haploid gametes. During meiosis a single round of DNA replication is followed by two rounds of chromosome segregation. In the first, or reductional, division (meiosis I), which is unique to meiotic cells, homologous chromosomes segregate from one another, whereas in the second, or equational, division (Meiosis II) sister centromeres disjoin. Meiotic DNA replication precedes the initiation of recombination by programmed Spo11-dependent DNA double-strand breaks. Recent reports that meiosis-specific cohesion is established during meiotic S phase and that the length of S phase is modified by recombination factors (Spo11 and Rec8) raise the possibility that replication plays a fundamental role in the recombination process.

RESULTS

To address how replication influences the initiation of recombination, we have used mutations in the B-type cyclin genes CLB5 and CLB6, which specifically prevent premeiotic replication in the yeast Saccharomyces cerevisiae. We find that clb5 and clb5 clb6 but not clb6 mutants are defective in DSB induction and prior associated changes in chromatin accessibility, heteroallelic recombination, and SC formation. The severity of these phenotypes in each mutant reflects the extent of replication impairment.

CONCLUSIONS

This assemblage of phenotypes reveals roles for CLB5 and CLB6 not only in DNA replication but also in other key events of meiotic prophase. Links between the function of CLB5 and CLB6 in activating meiotic DNA replication and their effects on subsequent events are discussed.

Disruption and functional analysis of six ORFs on chromosome XV: YOL117w, YOL115w ( TRF4), YOL114c, YOL112w ( MSB4), YOL111c and YOL072w

We have carried out the systematic disruption of six ORFs on chromosome XV, of Saccharomyces cerevisiae using the long flanking homology technique to replace each with the KanMX cassette; we have also constructed plasmids containing replacement cassettes and cognate clones for each ORF. Disruption of three of the ORFs-YOL117w, YOL114c, and YOL112w (also known as MSB4)-does not result in any noteworthy phenotype with respect to temperature or nutritional requirements, but yol112w mutants with an additional disruption of YNL293w, which encodes a protein similar to Yol112w, exhibit a slow growth phenotype. The protein specified by YOL114c shares similarity with the human DS-1 protein. Disruption of YOL115w confers slow growth, cold sensitivity and poor sporulation; this ORF has been described elsewhere as TRF4, which encodes a topoisomerase I-related protein. Cells with disruptions of YOL111c, whose product is weakly similar to the human ubiquitin-like protein GdX, are slightly impaired in mating. Mutants disrupted for YOL072w, the predicted product of which is unrelated to any protein of known function, grow slowly, are cold-sensitive and sporulate with reduced efficiency.

Disruption and functional analysis of seven ORFs on chromosome IV: YDL057w, YDL012c, YDL010w, YDL009c, YDL008w (APC11), YDL005c (MED2) and YDL003w (MCD1)

In the context of the EUROFAN project, we have carried out the systematic disruption of seven ORFs on chromosome IV of Saccharomyces cerevisiae using the long flanking homology technique to replace each ORF with the KanMX cassette. Targeted disruption of YDL057w, YDL012c, or YDL010w with YDL009c (the two ORFs overlap) confers no overt defects in haploid growth on a variety of media at different temperatures, in mating, or in the sporulation of diploids homozygous for the disruption. By contrast, YDL008w and YDL003w disruptants are non-viable. The product of YDL008w (elsewhere identified as APC11) is a component of the anaphase promoting complex. YDL003w (also termed MCD1) is a homologue of Schizosaccharomyces pombe rad21, an essential gene implicated in DNA double-strand break repair and nuclear organization in fission yeast. In budding yeast, this ORF has been shown by several laboratories to encode a protein involved in sister chromatid cohesion and chromosome condensation. The remaining ORF, YDL005c (also termed MED2), encodes a component of the transcriptional activator complex known as Mediator. Disruption of YDL005c confers a modest slow growth phenotype on rich medium and a more severe phenotype on minimal medium, aberrant cellular morphology, and mating defects; diploids homozygous for the disruption cannot sporulate.

Recombination at work for meiosis

In sexually reproducing organisms, homologous recombination increases genetic diversity in gametes and ensures proper chromosome segregation. Recent publications have provided details of the molecular intermediates and proteins involved, the control of the distribution of recombination events at the chromosomal level, and the surveillance mechanisms that coordinate recombination with the meiotic cell cycle.

Nucleotide sequences of nuclear tRNA(Cys) genes from Nicotiana and Arabidopsis and expression in HeLa cell extract

We have recently characterized Nicotiana cytoplasmic (cyt) tRNA(GCA)Cys as a novel UGA suppressor tRNA. Here we have isolated its corresponding (NtC1) and a variant (NtC2) gene from a genomic library of Nicotiana rustica. Both tRNA(Cys) genes are efficiently transcribed in HeLa cell nuclear extract and yield mature cyt tRNAs(Cys). Sequence analysis of the upstream region of the RAD51 single-copy gene of the Arabidopsis thaliana genome revealed a cluster of three tRNA(Cys) genes which have the same polarity and comprise highly similar flanking sequences. Of the three Arabidopsis tRNA(Cys) genes only one (i.e. AtC2) appears to code for a functional gene which exhibits an almost identical nucleotide sequence to NtC1. These are the first sequenced nuclear tDNAs(Cys) of plant origin.

Induction by cells of immune responses to intestinal epithelial cell-associated components (ECAC): transfer with cultured murine mesenteric and popliteal/axillary lymph node cells

Although systemic and mucosal immune responses to intestinal epithelial self-antigens occur in several human disorders, there is no model system with which to study the physiology and regulation of the underlying cellular events. Therefore, we undertook to induce an immune response to purified epithelial macromolecules in the Lewis rat; characterize in vitro the reactive cells; and then transfer with immunocytes this antiepithelial reactivity to naive syngeneic rats, identifying the fine specificity and site of humoral and cell-mediated immunity induced in the cell recipient. Donor animals sensitized systemically (via footpad) or locally in gut mucosa (via Peyer's patches) to syngeneic or xenogeneic epithelial antigens generated specific immunoglobulin and were found to have T lymphocytes in the draining nodal areas (including the mesenteric nodes) which were (a) antigen-specific, having a [3H]thymidine uptake in the presence of antigen 30-fold the control; (b) generally of the Thelper/inducer subclass (W3/25+) which, upon further culture, developed phenotype surface markers for activation (IL-2R+); (c) able to induce an antigen-specific humoral and cell-mediated responses upon intravenous injection into naive syngeneic hosts; and (d) demonstrable in gut-associated lymphoid tissue (mesenteric lymph nodes) and, to a lesser extent in spleen, of the cell recipient. Further, lymphocytes cloned from reactive mesenteric lymph node cells demonstrated specificity for a gel-purified subfraction of epithelial antigen, designated P1, containing highly conserved organ-specific macromolecules thought to be autoantigenic for gut.

Evaluation of 60 chemicals in a preliminary developmental toxicity test

The number of chemicals in commerce which have not been evaluated for potential developmental toxicity is large. Because of the time and expense required by conventional developmental toxicity tests, an abbreviated assay is needed that will preliminarily evaluate otherwise untested chemicals to help prioritize them for conventional testing. A proposed short-term in vivo assay has been used in a series of studies in which a total of 60 chemicals were tested. Some were independently tested two or four times each. In this preliminary test, pregnant mice were dosed during mid-pregnancy and were then allowed to deliver litters. Litter size, birth weight, and neonatal growth and survival to postnatal day 3 were recorded as indices of potential developmental toxicity. Results in this assay and conventional mouse teratology tests were generally concordant. Conventional data were available for 14 chemicals (ten teratogens, one fetotoxin, three nonteratogens), of which 11 (nine teratogens, one fetotoxin, one nonteratogen) produced evidence of developmental toxicity. This included conventional data for three chemicals (ethylene glycol, diethylene glycol dimethyl ether, and triethylene glycol dimethyl ether) that were untested before the present study. As high priority candidates for conventional testing on the basis of results here, all were subsequently studied in a standard teratology assay and were confirmed to be teratogenic in mice. Additionally, one of them (ethylene glycol) plus a fourth high priority candidate for conventional study (diethylene glycol monomethyl ether) were subsequently tested in rats and were found to be teratogenic in that species.