A review on mechanobiology of cell adhesion networks in different stages of sporadic colorectal cancer to explain its tumorigenesis

Sporadic colorectal cancer (CRC) is strongly linked to extraneous factors, like poor diet and lifestyle, but not to inherent factors like familial genetics. The changes at the epigenomics and signalling pathways are known across the sporadic CRC stages. The catch is that temporal information of the onset, the feedback loop, and the crosstalk of signalling and noise are still unclear. This makes it challenging to diagnose and treat colon cancer effectively with no relapse. Various microbial cells and native cells of the colon, contribute to sporadic CRC development. These cells secrete autocrine and paracrine for their bioenergetics and communications with other cell types. Imbalances of the biochemicals affect the epithelial lining of colon. One side of this epithelial lining is interfacing the dense colon tissue, while the other side is exposed to microbiota and excrement from the lumen. Hence, the epithelial lining is prone to tumorigenesis due to the influence of both biochemical and mechanical cues from its complex surrounding. The role of physical transformations in tumorigenesis have been limitedly discussed. In this context, cellular and tissue structures, and force transductions are heavily regulated by cell adhesion networks. These networks include cell anchoring mechanism to the surrounding, cell structural integrity mechanism, and cell effector molecules. This review will focus on the progression of the sporadic CRC stages that are governed by the underlaying cell adhesion networks within the epithelial cells. Additionally, current and potential technologies and therapeutics that target cell adhesion networks for treatments of sporadic CRC will be incorporated.

Abstract P6-08-02: Developing in vitro models of ductal carcinoma in situ from primary tissue

BACKGROUND: Because there are currently no reliable predictors for progression of ductal carcinoma in situ (DCIS) to invasive disease, nearly all patients receive aggressive therapy, leading to over-treatment in many cases. Few in vitro models for studying DCIS progression have been developed. We report here the successful culture and expansion of primary DCIS from surgical specimens using a conditional reprogramming protocol.

MATERIALS AND METHODS: From 2/2014 to 4/2015, patients with percutaneous core needle biopsy demonstrating DCIS were enrolled in a tissue banking protocol after informed consent was received. Under supervision of the surgical pathologist, fresh tissue measuring between 5-15 mm in length was taken from lumpectomy or mastectomy specimens. Tissue was divided such that half was mechanically and enzymatically dissociated and then cultured in medium conditioned by irradiated mouse fibroblasts and supplemented with rho-associated protein kinase (ROCK) inhibitor, and the second half, known as the "mirror image" remained as part of the clinical specimen.

RESULTS: Of 49 consented patients, mean age was 59 ± 10 years. 7 were excluded due to final pathology not consistent with DCIS: 4 upstaged to invasive ductal cancer, 2 had microinvasion and 1 showed pleomorphic lobular carcinoma in situ. Of the remaining 42, 9 were failures: 5 tissues were not received in lab and 4 cases were received, but no cells grew in culture. Of the remaining 33 cases of DCIS, 70% (n=23) and 27% (n=9) were nuclear grade 2 and 3 respectively. 91% (n=30) were ER-positive, with H-score ranging between 4 and 300. 19 (58%) were expanded in cell culture for up to two months in culture, and 14 were frozen immediately after mechanical dissociation for future growth. The 19 cell cultures could be cryopreserved and expanded. The cultures are almost exclusively composed of cytokeratin 8- and EpCAM-positive luminal cells and cytokeratin 14-, cytokeratin 5-, and p63-positive basal mammary epithelial cells, suggesting maintenance of heterogeneity in vitro. Furthermore, as assessed by luminal and basal marker expression, these cells retain their cellular identities both in the "conditionally reprogrammed" proliferative state and when conditioned media and ROCK inhibitor were withdrawn. When grown to 100% confluency, the cultures appear to organize into luminal and basal layers as well as luminal compartments surrounded by basal cells.

CONCLUSION: Primary cultures of DCIS derived directly from patient tissues may serve as in vitro models for the study of DCIS.

Citation Format: McAuliffe PF, Brown DD, Oesterreich S, Lee AV, Johnson RR, McGuire KP, Davidson NE, Brufsky AM, Dabbs DJ. Developing in vitro models of ductal carcinoma in situ from primary tissue. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-08-02.

Neonatal experience interacts with adult social stress to alter acute and chronic Theiler's virus infection

Previous research has shown that neonatal handling has prolonged protective effects associated with stress resilience and aging, yet little is known about its effect on stress-induced modulation of infectious disease. We have previously demonstrated that social disruption stress exacerbates the acute and chronic phases of the disease when applied prior to Theiler's virus infection (PRE-SDR) whereas it attenuates disease severity when applied concurrently with infection (CON-SDR). Here, we asked whether neonatal handling would protect adult mice from the detrimental effects of PRE-SDR and attenuate the protective effects of CON-SDR on Theiler's virus infection. As expected, handling alone decreased IL-6 and corticosterone levels, protected the non-stressed adult mice from motor impairment throughout infection and reduced antibodies to myelin components (PLP, MBP) during the autoimmune phase of disease. In contrast, neonatal handling X PRE/CON-SDR elevated IL-6 and reduced corticosterone as well as increased motor impairment during the acute phase of the infection. Neonatal handling X PRE/CON-SDR continued to exacerbate motor impairment during the chronic phase, whereas only neonatal handling X PRE-SDR increased in antibodies to PLP, MOG, MBP and TMEV. Together, these results imply that while handling reduced the severity of later Theiler's virus infection in non-stressed mice, brief handling may not be protective when paired with later social stress.

Abstract P5-14-15: Contralateral Prophylactic Mastectomy: Clinical and Pathological Features of Women Treated at the University of Louisville

Objective: To evaluate the clinical and pathological features of women who underwent contralateral prophylactic mastectomy (CPM) as a component of breast cancer therapy.

Materials & Methods: This is a retrospective review of a prospectively-maintained database of patients treated at the multi-disciplinary breast cancer clinic at the University of Louisville from 2003-2009. Patientswith unilateral pre-invasive and invasive adenocarcinoma who underwent mastectomy as primary surgical treatment for the involved breast with CPM were included. All information from surgical, medical and radiation oncology records were reviewed for this analysis.

Results: A total of 107 patients are included in this analysis. The median age was 48 years (range 26-80). A previous history of breast cancer was noted in 8% of patients, all of whom received lumpectomy and whole-breast radiotherapy. A family history of breast cancer was identified in 46% of patients and 4% of patients possessed a germline BRCA mutation. Ninety-three percent of tumors were invasive. Evaluation of the pathological tumor (T) stage yielded 7% Tis, 48% T1, 36% T2, 3% T3, and 3% T4. Four percent of tumors were pathologically T0 after a complete response to neoadjuvant chemotherapy. Pathological node (N) staging yielded 56% N0, 23% N1, 14% N2, and 7% N3. Two percent of patients had distant metastasis at diagnosis. Twenty-two percent of tumors were negative for the estrogen, progesterone, and HER2/neu receptors (triple negative). Lobular carcinoma in situ was found in 10% of tumors. Five occult tumors were detected in the contralateral breast, of which 4 were carcinoma in situ and 1 was invasive mucinous carcinoma. With a median follow-up of 27 months (range 7-83), 9 treatment failures have been noted. Four patients failed locoregionally, 3 failed distantly, and 2 failed both locoregionally and distantly. Five patients have died of metastatic disease. No contralateral chest wall failures have occurred.

Conclusions: CPM has become more popular over the past 6 years and patients present with a diverse array of clinical and pathological features. Occult disease in the contralateral breast is rare and was not encountered in our series. The pattern of failure is determined by the primary disease and the clinical utility of CPM therefore remains uncertain.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P5-14-15.

Transfer vectors for maximal expression of passenger genes in the Bombyx mori nuclear polyhedrosis virus expression system

A series of Bombyx mori nuclear polyhedrosis virus (Bm-NPV) transfer vectors has been developed containing various lengths of the polyhedrin promoter, including sequences 3' of the initiation codon. The ATG initiation codon was mutated in some of these vectors to allow for the production of authentic nonfusion proteins. The ability of the various polyhedrin promoter constructs to direct expression of foreign gene sequences was assessed using two test genes, chloramphenicol acetyl transferase (cat), and human metallothionein II. Accumulation of cat mRNA and nonfused protein was low when only polyhedrin promoter sequences to -8 (relative to the translational start site of polyhedrin mRNA) were included in the transfer vector, but cat expression was comparable with that of the wild-type polyhedrin gene when promoter sequences to +5 were present. Further addition of polyhedrin gene sequences to +26 or +94 resulted in no further increase in expression. Similar results were obtained for expression of human metallothionein II, where constructs encoding polyhedrin-metallothionein fusion proteins containing polyhedrin sequences to at least +5 resulted in high levels of mRNA and protein accumulation. The expression vectors containing the +5, +26, or +94 BmNPV polyhedrin promoter can thus be used to direct maximal levels of production of nonfused proteins (when the polyedrin ATG has been mutated) or of fusion proteins, depending on which is more suitable for a particular application. These new vectors are a useful addition to those presently available and should increase the utility of the BmNPV expression system for large-scale protein production.

Neonatal maternal separation alters immune, endocrine, and behavioral responses to acute Theiler's virus infection in adult mice

Previous studies have established a link between adverse early life events and subsequent disease vulnerability. The present study assessed the long-term effects of neonatal maternal separation on the response to Theiler's murine encephalomyelitis virus infection, a model of multiple sclerosis. Balb/cJ mouse pups were separated from their dam for 180-min/day (180-min MS), 15-min/day (15-min MS), or left undisturbed from postnatal days 2-14. During adolescence, mice were infected with Theiler's virus and sacrificed at days 14, 21, or 35 post-infection. Prolonged 180-min MS increased viral load and delayed viral clearance in the spinal cords of males and females, whereas brief 15-min MS increased the rate of viral clearance in females. The 15-min and 180-min MS mice exhibited blunted corticosterone responses during infection, suggesting that reduced HPA sensitivity may have altered the immune response to infection. These findings demonstrate that early life events alter vulnerability to CNS infection later in life. Therefore, this model could be used to study gene-environment interactions that contribute to individual differences in susceptibility to infectious and autoimmune diseases of the CNS.

Restraint stress decreases virus-induced pro-inflammatory cytokine mRNA expression during acute Theiler's virus infection

Stressful life events have been associated with the onset and/or exacerbation of multiple sclerosis (MS). Our previous studies have indicated that restraint stress (RS) reduces inflammation and virus-induced chemokine expression in the Theiler's virus-induced demyelination (TVID) model of MS. Here we report that RS significantly reduced the virus-induced interferon-gamma mRNA levels in the brain. Additionally, mRNA levels of lymphotoxin-beta, tumor necrosis factor-alpha, and interferon-gamma in the brain were negatively correlated with viral titers in the brain. These results indicated an immunosuppressive effect of stress during early TVID causing impaired viral clearance, which may be a potential exacerbating factor for later demyelination.

Alterations in chemokine expression following Theiler's virus infection and restraint stress

Restraint stress (RS) applied to mice during acute infection with Theiler's virus causes corticosterone-induced immunosuppression. This effect was further investigated by measuring chemokine changes in the spleen and central nervous system (CNS) using an RNase Protection Assay. mRNAs for lymphotactin (Ltn), interferon-induced protein-10 (IP-10), MIP-1 beta, monocyte chemoattractant protein-1 (MCP-1) and TCA-3 were detected in the spleen at day 2 pi, but not in the brain of CBA mice infected with Theiler's virus. Ltn, IP-10 and RANTES were elevated in both the spleen and the brain at day 7 pi, and were significantly decreased by RS in the brain. RS also resulted in decreased inflammation within the CNS.

Social stress alters the severity of acute Theiler's virus infection

Our laboratory has previously shown that restraint stress resulted in decreased Theiler's virus-induced CNS inflammation, while exacerbating illness behaviors during the acute phase of disease. In contrast, social disruption stress (SDR) applied prior to infection led to the development of glucocorticoid (GC) resistance, and these animals developed more severe disease course, with increased inflammation. However, when SDR was applied concurrent with infection, GC resistance fails to develop, disease course is less severe and inflammation was moderate. These results suggest that the effects of SDR on Theiler's virus infection are dependent upon the timing of SDR application in relation to infection.

Psychosocial issues near the end of life

End-of-life care has received increasing attention in the last decade; however, the focus continues to be on the physical aspects of suffering and care to the virtual exclusion of psychosocial areas. This paper provides an overview of the literature on the intra- and interpersonal aspects of dying, including the effects that psychosocial variables have on end-of-life decision-making; common diagnosable mental disorders (e.g., clinical depression, delirium); other types of personal considerations (e.g., autonomy/control, grief); and interpersonal/environmental issues (e.g., cultural factors, financial variables). Six roles that qualified mental health professionals can play (i.e., advocate, counselor, educator, evaluator, multidisciplinary team member, and researcher) are also outlined. Because psychosocial issues are ubiquitous and can have enormous impact near the end of life, properly trained mental health professionals can play vital roles in alleviating suffering and improving the quality of life of people who are dying.

A non-hypersensitive resistance in pepper to the bacterial spot pathogen is associated with two recessive genes

ABSTRACT The pepper genotype, ECW-12346, was developed with bacterial spot resistance derived from Pep13, PI 271322, and ECW123 (Early Calwonder containing Bs1, Bs2, and Bs3 genes). For genetic analysis of this resistance, ECW12346, ECW123, F(1), F(2), and backcrosses were inoculated with a pepper race 6 (P6) strain. Two recessive genes were identified that determined resistance. The genes are designated bs5 and bs6 for the resistance derived from PI 271322 and Pep13, respectively. In greenhouse and field studies, ECW12346 was highly resistant, whereas ECW123 had significant defoliation. In growth-room studies, electrolyte leakage and population dynamics were determined. Following infiltration of both genotypes with 10(8) CFU/ml of a P6 strain, there was no rapid increase in electrolyte leakage within 72 h, whereas a rapid increase in electrolyte leakage occurred within 24 h when a similar concentration of a P3 strain (containing the avrBs2 gene) was infiltrated into the intercellular spaces of the leaf. When 10(5) CFU/ml of a P6 strain was infiltrated into leaves, complete tissue collapse was evident in ECW123 10 days later as determined by visual assessment and electrolyte leakage data, but no confluent necrosis was detected in ECW12346. Internal populations were at least two logarithmic units higher in ECW123 than in ECW12346. Therefore, ECW12346 inhibits population build-up without inducing the typical hypersensitive reaction characterized by an increase in electrolyte leakage.

The relationship of blunt head trauma, subarachnoid hemorrhage, and rupture of pre-existing intracranial saccular aneurysms

Patients with a history of closed head trauma and subarachnoid hemorrhage are uncommonly diagnosed with an intracranial saccular aneurysm. This study presents a group of patients in whom a pre-existing aneurysm was discovered during work-up for traumatic subarachnoid hemorrhage. Without an accurate pre-trauma clinical history, it is difficult to define the relationship between trauma and the rupture of a pre-existing intracranial saccular aneurysm. We retrospectively reviewed 130 patients who presented to Detroit Receiving Hospital between 1993 and 1997 with a diagnosis of subarachnoid hemorrhage (SAH). Of these 130 patients, 70 were spontaneous, and 60 had a history of trauma. Mechanisms of trauma include motor vehicle accident, assault, or fall from a height. Of the 60 patients with subarachnoid hemorrhage and a history of trauma, 51 (86%) did not undergo conventional four-vessel angiography, and had no further neurological sequelae. Nine patients (14%) had a suspicious quantity of blood within the basal cisterns or Sylvian fissure and had a four-vessel angiogram. Five patients (8%) were diagnosed with a saccular intracranial aneurysm, and all underwent surgical clipping of the aneurysm. We conclude that the majority of patients (92%), with post-traumatic SAH do not harbor intracranial aneurysms. However, during initial evaluation, a high level of suspicion must be entertained when post-traumatic subarachnoid hemorrhage is encountered in the basal cisterns or Sylvian fissure, as 8% of our population were diagnosed with aneurysms.

The separation of anatomic components technique for the reconstruction of massive midline abdominal wall defects: anatomy, surgical technique, applications, and limitations revisited

Reconstruction of massive abdominal wall defects has long been a vexing clinical problem. A landmark development for the autogenous tissue reconstruction of these difficult wounds was the introduction of "components of anatomic separation" technique by Ramirez et al. This method uses bilateral, innervated, bipedicle, rectus abdominis-transversus abdominis-internal oblique muscle flap complexes transposed medially to reconstruct the central abdominal wall. Enamored with this concept, this institution sought to define the limitations and complications and to quantify functional outcome with the use of this technique. During a 4-year period (July of 1991 to 1995), 22 patients underwent reconstruction of massive midline abdominal wounds. The defects varied in size from 6 to 14 cm in width and from 10 to 24 cm in height. Causes included removal of infected synthetic mesh material (n = 7), recurrent hernia (n = 4), removal of split-thickness skin graft and dense abdominal wall cicatrix (n = 4), parastomal hernia (n = 2), primary incisional hernia (n = 2), trauma/enteric sepsis (n = 2), and tumor resection (abdominal wall desmoid tumor involving the right rectus abdominis muscle) (n = 1). Twenty patients were treated with mobilization of both rectus abdominis muscles, and in two patients one muscle complex was used. The plane of "separation" was the interface between the external and internal oblique muscles. A quantitative dynamic assessment of the abdominal wall was performed in two patients by using a Cybex TEF machine, with analysis of truncal flexion strength being undertaken preoperatively and at 6 months after surgery. Patients achieved wound healing in all cases with one operation. Minor complications included superficial infection in two patients and a wound seroma in one. One patient developed a recurrent incisional hernia 8 months postoperatively. There was one postoperative death caused by multisystem organ failure. One patient required the addition of synthetic mesh to achieve abdominal closure. This case involved a thin patient whose defect exceeded 16 cm in width. There has been no clinically apparent muscle weakness in the abdomen over that present preoperatively. Analysis of preoperative and postoperative truncal force generation revealed a 40 percent increase in strength in the two patients tested on a Cybex machine. Reoperation was possible through the reconstructed abdominal wall in two patients without untoward sequela. This operation is an effective method for autogenous reconstruction of massive midline abdominal wall defects. It can be used either as a primary mode of defect closure or to treat the complications of trauma, surgery, or various diseases.

Usefulness of tissue marker clips in patients undergoing neoadjuvant chemotherapy for breast cancer

OBJECTIVE

The purpose of this study was to evaluate the usefulness of a tissue marker clip in patients undergoing preoperative chemotherapy for breast carcinoma.

MATERIALS AND METHODS

Between June 1996 and July 1998 (26 months), a tissue marker clip was placed in 29 patients with breast carcinoma who showed significant clinical response to preoperative chemotherapy. In these patients, 13 clips were placed stereotactically and 16 clips were placed using sonographic guidance. A retrospective review of these cases was made to evaluate helpfulness of the clip during preoperative needle localization.

RESULTS

One patient relocated to another city, so surgical follow-up was available in 28 patients. Twenty-four of these 28 patients required preoperative wire localization and four still had a palpable tumor at the time of surgery. Preoperative wire localization would have been possible without any difficulty in eight patients (28.6%), possible but with some difficulty in six patients (21.4%), and impossible in 10 patients (35.7%) without the clip. Thus, clip placement was valuable in 16 (57.1%) of 28 patients at the time of preoperative needle localization.

CONCLUSION

With the newer chemotherapeutic agents, the response of breast carcinoma to preoperative chemotherapy may be dramatic. In some patients, the tumor is no longer visible either on mammography or sonography, thus making the preoperative needle localization difficult or even impossible. By placing a radiopaque marker before the lesion becomes unidentifiable, one can confidently localize the tumor bed at surgery.

Degradation of oat mRNAs during seed development

The genes AV1, AV10, and Z1 encode proteins that accumulate during oat seed development. In developing endosperm of Avena sativa (cultivated oat), AV1, AV10 and Z1 mRNAs reach maximal levels midway through seed development but fall to very low levels in mature seeds. Similarly, mRNAs for these proteins peak during endosperm development of Avena fatua (wild oat) and are later degraded. However, during late maturation of A. fatua seeds, populations of mRNA fragments shorter than the intact transcripts accumulate as the full-length transcripts decline in abundance. The smaller RNA molecules, which are apparently long-lived decay intermediates, are derived randomly from the entire transcripts and are most likely not generated by cleavage at precisely defined sites. Other A. fatua endosperm mRNAs that are degraded during late seed development, such as those for ADP glucose pyrophosphorylase and starch synthase, do not produce detectable decay intermediates. Decay intermediates of AV1 and Z1 mRNAs persist at high levels during late seed development of two other undomesticated oat species, Avena strigosa and Avena barbata. The persistence of decay intermediates for these endosperm mRNAs in wild grass species may represent a model system for studying RNA decay process in plant tissues.

A polysynaptic feedback circuit in rat visual cortex

Feedback connections from extrastriate cortex to primary visual cortex (V1) in the primate may provide "top-down" information that plays a role in visual attention and object recognition. Our work in a rodent model of corticocortical circuitry demonstrates that feedback pathways synapse preferentially with pyramidal cells in V1 () and favor excitation over inhibition in cortical microcircuits (). To investigate the polysynaptic circuits activated by feedback inputs, we studied chains of neurons postsynaptic to feedback connections using a combination of axonal tract tracing and anterograde degeneration. This approach enabled independent labeling of local collaterals of forward-projecting neurons in V1 and feedback connections from extrastriate lateromedial (LM) visual area to V1. Postsynaptic targets were identified in the electron microscope after retrograde transport of biotinylated dextran amine (BDA) to identify dendrites of forward-projecting neurons (i.e., from V1 to LM) and postembedding immunogold labeling to identify GABAergic interneurons. The results show that feedback connections provide strong monosynaptic input to forward-projecting neurons in V1. These neurons in turn make local connections that preferentially form synapses with other pyramidal cells ( approximately 97%), many of which were identified as forward-projecting neurons. This indicates that feedback pathways provide input directly to neurons which make the reciprocal forward connection, and that feedback-recipient forward-projecting neurons are strongly interconnected. The function of these excitatory networks within V1 may be to amplify feedback activity and provide a circuit for modulation of striate cortical activity by top-down influences.

Breast care consultation center: role of the pathologist in a multidisciplinary center

The Breast Care Consultation Center (BCCC) is a multidisciplinary center providing, in a single setting, a complete outpatient facility for women who have been diagnosed with or suspected of having breast cancer. A team of specialists are available to provide comprehensive, diagnostic (radiologist, surgeon, and pathologist), therapeutic (surgeon, radiotherapist, and medical oncologist), and support options. The pathologist, as a member of the diagnostic team, evaluates the material obtained or received at the BCCC. These include fine-needle aspirations (FNAs) obtained on-site as well as previously prepared cytohistological specimens. The pathologist renders the diagnosis following examination of the material and consultation with the multidisciplinary team. Thus, this approach is conducive for appropriate and accurate diagnosis where all data are available. In addition, the pathologist discusses the findings of each patient in the multidisciplinary conference. One thousand four hundred eighteen patients were evaluated at Magee-Womens Hospital BCCC from February 1992 through December 1994, during which time 366 FNAs were performed. The accuracy for positive diagnosis was 100%. Six negative cases had cancer on histology; these were due to sampling error (the lesion was missed). A multidisciplinary team is ideal for the evaluation of breast lesions that are suspicious for malignancy as it provides one-stop shopping and same-day diagnosis and therapeutic decisions.

Intestinal absorption of trace amounts of aluminium in rats studied with 26aluminium and accelerator mass spectrometry

1. Until recently studies of intestinal aluminium absorption used pharmacological amounts of stable 27Al. 2. To examine the intestinal absorption of trace amounts of different chemical compounds of aluminium, in the present study we have employed the long half-life isotope of aluminium, 26Al, and accelerator mass spectrometry. Trace amounts of 26Al (2.7-12.1 ng) as the hydroxide, citrate, citrate plus 1 mmol/kg sodium citrate, or maltolate respectively, were administered to four groups of rats (n = 9 per group) by gavage. Blood and urine samples were collected for 5 h and the 26Al content (as a percentage of the administered dose) determined by accelerator mass spectrometry. 3. The 5 h urinary 26Al excretion amounted to 0.1 +/- 0.02, 0.7 +/- 0.2, 5.1 +/- 1.5 and 0.1 +/- 0.1% of administered dose in the four groups respectively. There was a strong positive correlation between peak plasma 26Al (r = 0.98) and urinary 26Al excretion in individual animals (P < 0.001). 4. We conclude that the fractional intestinal absorption of trace oral doses of aluminium hydroxide is at least 0.1% (compared with the previous estimate of 0.01% using large 27Al oral loads). Absorption of aluminium citrate given alone is significantly greater (0.7%) and is further increased to 5% by the accompanying sodium citrate, consistent with an enhancing effect of added citrate upon mucosal aluminium permeability. Aluminium maltolate absorption approximates that of aluminium hydroxide (0.1%).

The neurovascular complications of cocaine

BACKGROUND

Cocaine use has been temporally associated with neurovascular complications, including the rupture of intracerebral aneurysms. The purpose of the current study was to determine the type of neurovascular complications associated with cocaine use in our patient population, the temporal relationship between cocaine use and their onset, and whether cocaine users with subarachnoid hemorrhage (SAH) presented with smaller aneurysms at an earlier age than a control group of noncocaine users with SAH.

METHODS

Thirty-three patients who presented to the Detroit Medical Center with neurovascular sequelae associated with cocaine use were identified. All patients were chronic cocaine users who related a history of recent use confirmed by a drug screen. Cocaine users with SAH were compared to a control group of 44 patients with SAH who presented without evidence of cocaine use.

RESULTS

Sixteen patients presented with SAH. Twelve patients subsequently underwent four-vessel cerebral arteriogram revealing 14 aneurysms; six patients presented with intracerebral hemorrhage (ICH) and seven patients with evidence of ischemic stroke. Eighteen (54.5%) patients noted onset of their symptoms while using cocaine, 87.9% noted onset within 6 hours of use. Delayed presentation occurred predominantly in patients who suffered ischemic strokes. The average age of patients who used cocaine and presented with SAH secondary to a ruptured intracerebral aneurysm was 32.8 years with an average aneurysm diameter of 4.9 mm versus an average age of 52.2 years with an average aneurysm diameter of approximately 11.0 mm in noncocaine users. Population differences were statistically significant at the p < 0.05 level. Mortality was 27.3% for patients who presented with neurovascular sequelae of their cocaine use, with 77.8% of deaths occurring in patients who presented with SAH.

CONCLUSIONS

Chronic cocaine use appears to predispose patients who harbor incidental neurovascular anomalies to present at an earlier point in their natural history than similar non-cocaine users.

Microcircuitry of forward and feedback connections within rat visual cortex

Visual cortex in mammals is composed of many distinct areas that are linked by reciprocal connections to form a multilevel hierarchy. Ascending information is sent via forward connections from lower to higher areas and is thought to contribute to the emergence of increasingly complex receptive field properties at higher levels. Descending signals are transmitted via feedback connections from higher to lower areas and are believed to provide information about the context in which a stimulus appears, to contribute to modulation of visual responses by attention, and to play a role in memory processes. To determine whether forward and feedback pathways in rat visual cortex constitute distinct intracortical circuits, we have studied the distribution of reciprocal corticocortical inputs to pyramidal cells and gamma-aminobutyric acid (GABA)ergic interneurons. For this purpose, we chose forward and feedback connections between primary visual cortex and the secondary extrastriate lateromedial (LM) area as a model system. Pathways were traced with the axonal marker phaseolus vulgaris-leucoagglutinin. Labeled terminals were identified in the electron microscope, and GABA immunocytochemistry was used to identify the postsynaptic dendritic shafts of GABAergic interneurons. In both pathways, inputs to pyramidal cells were directed preferentially to dendritic spines and not to shafts. In the forward pathway, 90% of labeled inputs were distributed to pyramidal cells and 10% to interneurons. This proportion was similar to that of nearby unlabeled connections in the neuropil, indicating that forward connections are not selective for pyramidal cells or interneurons. In sharp contrast, feedback connections were significantly different from the unlabeled connections and supplied almost exclusively pyramidal cells (98%). Feedback inputs to GABAergic neurons were five times weaker (2%) relative to the forward direction. These structural differences suggest that disynaptic GABAergic inhibition is much stronger in forward than in feedback pathways. Recent physiological experiments have confirmed this prediction (Shao et al. [1995] Soc. Neurosci. Abstr., 21:1274) and we, therefore, conclude that relatively small anatomical differences in the microcircuitry can have important functional consequences. It remains an open question whether generally reciprocal interareal circuits at all levels of the cortical hierarchy are organized in similar fashion.

Regional and laminar differences in synaptic localization of NMDA receptor subunit NR1 splice variants in rat visual cortex and hippocampus

Changes in N-methyl-D-aspartate (NMDA) receptor expression may represent a molecular substrate for differences in synaptic plasticity between early postnatal and adult brains (Fox and Zahs [1994] Curr. Opinion Neurobiol. 4:112-119). We have, therefore, examined the regional and laminar distribution of NR1, the essential subunit of the NMDA receptor, in two regions in which synaptic plasticity has been most thoroughly studied: primary visual cortex and hippocampus. To study NR1 expression at the light and electron microscopic levels we have used a new antiserum (NR1-C1; Sheng et al. [1994] Nature 368:144-147) directed against a differentially spliced C-terminal exon ("C1"). The most striking result was that the pattern of NR1-C1 labeling in the adult was more restricted than that of previously published NR1-specific antibodies. Specifically, NR1-C1 did not label cells in the CA3, dentate gyrus or subicular regions of the hippocampus or in layer 4 of the visual cortex. Quantitative ultrastructural analysis revealed that these differences were paralleled by differential expression of NR1-C1 at synapses. In sharp contrast to the pattern in the adult, NR1-C1 immunoreactivity was distributed more widely in the developing brain. At postnatal day 11, NR1-C1 splice variants were expressed in all layers of the visual cortex and in all regions of the hippocampus. The transient expression of NR1-C1 splice variants in layer 4 of visual cortex suggests that NR1-C1 may play a role in determining the critical period for binocular plasticity. Continued expression of NR1-C1 in upper and lower layers of the adult cortex and in CA1 of the hippocampus may provide a substrate for plasticity in corticocortical connections and Schaffer collateral synapses beyond the critical period. In addition to abundant postsynaptic staining, NR1-C1 immunoreactivity was found in a large number of axon terminals in the dorsal subiculum, but in very few terminals in visual cortex. This strongly suggests that presynaptic NMDA receptors play a major role in neuronal processing of hippocampal output through the subiculum, but play a relatively minor role in visual processing.

Trans-activation of a cell housekeeping gene promoter by the IE1 gene product of baculoviruses

Protein IE1 is the product of a baculovirus gene, ie1, that is activated immediately upon entrance of the viral genome into the cell nucleus. This protein was previously shown to be a trans-regulator of viral genes whose products are required for initiation of the infectious cycle including viral DNA replication. To test whether the IE1 protein is also capable of trans-regulating nuclear genes of the host in vitro and in vivo, we transfected the ie1 gene of Bombyx mori nuclear polyhedrosis virus (BmNPV) into silkworm Bm5 tissue culture cells together with expression cassettes directing expression of chloramphenicol acetyl transferase or juvenile hormone esterase under the control of the cytoplasmic actin A3 gene promoter of B. mori. Cotransfection with the ie1 gene resulted in a dramatic increase in the amount of the two enzymes expressed in the transfected cells. The increased enzyme activities correlate with an increased accumulation of the corresponding mRNAs, and the latter is caused by an increase in the rate of transcription directed by the cytoplasmic actin gene promoter. The chromosomal cytoplasmic actin gene of Bm5 cells is also upregulated upon transfection of the cells with the ie1 gene. However, infection of cells with BmNPV does not cause an increase in the level of expression of the endogenous cytoplasmic actin gene. Thus, the effect of IE1 on the transcriptional properties of the cytoplasmic actin gene vary depending on whether IE1 is expressed in isolation or in the context of a viral infection. The trans-activating effects of BmNPV ie1 gene expression on the silkmoth actin promoter are also evident in Spodoptera frugiperda Sf21 and Choristoneura fumiferana Cf1 tissue culture cells. Finally, the ie1 gene of Autographa californica nuclear polyhedrosis virus can substitute for its BmNPV counterpart in all cell lines tested.

No continuous relationship between Veterans Affairs hospital coronary artery bypass grafting surgical volume and operative mortality

BACKGROUND

The purpose of this study was to determine whether risk-adjusted coronary artery bypass grafting mortality rates are significantly related to coronary artery bypass grafting surgical procedure volume within the Department of Veterans Affairs hospital system.

METHODS

From April 1987 to September 1992, expected mortality rates were calculated for 23,986 coronary artery bypass grafting procedures performed at 44 different Veterans Affairs hospitals.

RESULTS

This study found a statistically significant relationship between annual hospital coronary artery bypass grafting volume and observed mortality rates (p < 0.02). However, no statistically significant relationship between coronary artery bypass grafting volume and risk-adjusted operative mortality was found (p = 0.10). Using analysis of variance on hospital-level data, hospitals with 100 or less cases per year have higher observed to expected mortality ratios than hospitals performing more than 100 cases per year (p = 0.03). Using Poisson regression models, however, a volume threshold could not be found.

CONCLUSIONS

These findings are consistent with the current Veterans Affairs policy requirements to periodically review quality at low-volume hospitals.

Identification of Eimeria bovis merozoite cDNAs using differential mRNA display

Differences in gene expression between Eimeria bovis sporozoites and first-generation merozoites were analyzed using the technique of differential mRNA display. Approx. 5% of the sequences detected in first-generation merozoites appear to be unique relative to sporozoites. Several of the bands corresponding to merozoite-specific gene expression were isolated and cloned. Northern blot analysis revealed that the cDNA fragments DMZ-7, DMZ-8 and NMZ-6 hybridized to mRNAs expressed at > 50-fold higher levels in merozoites relative to sporozoites. A fourth cDNA fragment, NMZ-4, hybridized to a mRNA expressed at 3-fold higher levels in merozoites. Further characterization demonstrated that expression of DMZ-8 in E. bovis-infected bovine cells begins as early as 12 h after sporozoite invasion and continues throughout the entire 14 days of first-generation schizogony. Sequence analysis of each of the four merozoite cDNAs failed to identify any significant similarity to any entries in the GenBank database, suggesting that these developmentally regulated genes may be unique to coccidian parasites.

Characterization of cDNA clones for differentially expressed genes in embryos of dormant and nondormant Avena fatua L. caryopses

The molecular regulation of seed dormancy was investigated using differential display to visualize and isolate cDNAs representing differentially expressed genes during early imbibition of dormant and nondormant Avena fatua L. embryos. Of about 3000 cDNA bands examined, 5 cDNAs hybridized with mRNAs exhibiting dormancy-associated expression patterns during the first 48 h of inhibition, while many more nondormancy-associated cDNAs were observed. Dormancy-associated clone AFD1 hybridized with a 1.5 kb mRNA barely detectable in dry dormant and nondormant embryos that became more abundant in dormant embryos after 24 h of imbibition. Clone AFD2 hybridized with two mRNAs, a 1.3 kb message constitutively expressed in dormant and nondormant embryos and a 0.9 kb message present at higher levels in dormant embryos after 3 h of imbibition. Nondormancy-associated clones AFN1, AFN2 and AFN3 hybridized with 1.5 kb, 1.7 kb and 1.1 kb mRNAs, respectively, that were more abundant in nondormant embryos during imbibition. Expression patterns of some mRNAs in dormant embryos induced to germinate by GA3 treatment were different than water controls, but were not identical to those observed in nondormant embryos. DNA sequence analysis revealed 76% sequence identity between clone AFN3 and a Citrus sinensis glutathione peroxidase-like cDNA, while significant sequence similarities with known genes were not found for other clones. Southern hybridization analyses showed that all clones represent low (1 to 4) copy number genes.

Computational properties of self-reproducing growing automata

Living organisms perform much better than computers at solving complex, irregular computational tasks, like search and adaptation. Key features of living organisms, identified in the paper as a basis for their success in solving complex problems, are: self-reproduction of cells, flexible framework, and modification. These key features of living organisms are abstracted into a computational model, called growing automata. Growing automata are suited for extremely large computational problems, such as search problems. Growing automata are representatives of soft machines. Soft machines can change their physical structure as opposed to hard machines which have fixed structure. An example of a soft machine is a living organism, an example of a hard machine is an electronic computer. The computational properties of soft and hard machines are analyzed and compared. An analysis of growing automata demonstrates their advantages, as well as their limitations as compared to hard machines.

The Veterans Affairs Continuous Improvement in Cardiac Surgery Study

The Department of Veterans Affairs Cardiac Surgery Consultants Committee is responsible for reviewing the quality of cardiac surgical treatment at the 43 Veterans Affairs cardiac surgical centers where these procedures are performed. It does so by reviewing both the unadjusted and risk-adjusted operative mortality data and the incidence of perioperative complications. These data are reviewed by the committee semiannually, and the overall summary and hospital-specific data are shared with the individual cardiac surgical program directors. Paper audits and site visits are performed when indicated by increased unadjusted and risk-adjusted operative mortality. Constructive criticism is shared with the program director and medical center administration. The relative risk of death for numerous patient risk factors has been estimated, and is now used in prospective clinical decision making. During the 7-year period that risk-adjusted outcomes have been utilized, there has been an overall significant reduction in the observed-to-expected operative mortality ratio. Although many factors could have contributed to this, including continually improving surgical techniques, it is also likely that part of this improvement has occurred because of the continuous feedback of these quality improvement data to our cardiothoracic surgeons and cardiologists.

Developmental regulation of an Eimeria bovis mRNA encoding refractile body-associated proteins

Eimeria bovis antigens defined by the monoclonal antibody (mAb) 2.4 are associated with the refractile bodies of sporozoites and are found in the parasitophorous vacuole and host cell cytoplasm during schizogony. Screening of an E. bovis oocyst cDNA library with mAb 2.4 resulted in the identification of a single unique cDNA sequence (Eb-25/50). Comparison of the predicted protein sequence of Eb-25/50 revealed a high degree of identity to an Eimeria tenella refractile body protein and mAb 2.4 was found to cross-react with refractile bodies from Eimeria acervulina, demonstrating that these proteins are highly conserved among eimerian species. Measurements of Eb-25/50 mRNA showed that the multiple proteins recognized by mAb 2.4 are encoded by a single mRNA species whose kinetics of expression during sporulation and schizogony closely correlated with protein expression. Consistent with multiple Eb-25/50 proteins arising from a single polypeptide, results from a Southern analysis of E. bovis genomic DNA indicated that Eb-25/50 mRNA is derived from a single copy gene. The presence of Eb-25/50 proteins in the host cytoplasm during schizogony, the high degree of conservation of these proteins, and the apparent complex post-translational modification raises interesting questions about the biochemistry of these proteins during eimerian development.

The effect of film thickness on the bond strength of polycarboxylate cement

This study examined the bond strength of polycarboxylate cement when used to cement gold alloy specimens to dentin. The film thickness was controlled and varied over a range of 10 to 150 microns. Tensile and shear bond strengths were measured and, contrary to anticipated results, there was an increase in bond strength as the film thickness increased. In this study, the bond strength of polycarboxylate cement as it relates to film thickness is evaluated in relationship to the clinically significant value of 50 microns over the thickness range of 150 microns.

Gas chromatographic determination of total fat extracted from food samples using hydrolysis in the presence of antioxidant

A method for the quantitative measurement of total fat in foodstuffs is described. Fat is extracted by hydrolysis and inter-esterified to fatty acid methyl esters for gas chromatographic analysis. Total fat and fatty acid patterns are calculated to comply with the regulations for food label declaration under the Nutrition Labeling and Education Act of 1990. Quantitative recovery of fat from soy oil is obtained in the presence of the antioxidant pyrogallol. Extraction and measurements of fat from a variety of food samples (e.g., cereal, baked goods, dairy, and fish) are also reported, and fat levels ranged from 0.8 to 95% (w/w). Coefficients of variation of < or = 5% demonstrate the efficiency of the method.

Two-staged breast reconstruction in patients with symptomatic macromastia requiring mastectomy

Patients with symptomatic macromastia undergoing mastectomy for the treatment of malignant breast disease are candidates for a two-staged operation resulting in breast reconstruction and contralateral breast reduction. Five patients with symptomatic macromastia underwent a skin-sparing mastectomy for breast disease using a modified Wise incision. The first stage of the breast reconstruction was performed with a de-epithelialized transverse rectus abdominis musculocutaneous (TRAM) flap. Second-stage breast reconstruction was conducted 4 to 6 months later when revision of the TRAM reconstructed breast and concurrent contralateral breast reduction were performed with the intent of tailoring the reduced breast to approximate the revised TRAM breast mound. Excess areola from the reduced breast was harvested and used as a full-thickness graft to reconstruct the TRAM areola complex. Patients followed for 5 to 30 months postoperatively confirm resolution of macromastia symptoms, correction of the mastectomy defect, and symmetrical breast mound creation in a timely two-staged procedure. The two-staged breast reconstruction described represents an expedient plan for patients with symptomatic macromastia requiring mastectomy for breast disease. Skin-sparing mastectomy, modified Wise pattern incisions, utilization of usually discarded areola tissue, and creation of symmetrical breast mounds during the second stage of the reconstruction highlight the salient features of this patient management paradigm.

Complex interactions at a GC-rich domain regulate cell type-dependent activity of the ornithine decarboxylase promoter

Regulation of ornithine decarboxylase (ODC) is critical to the control of cellular growth, differentiation, and carcinogenesis. A GC-rich region in the ODC promoter contains two overlapping protein binding sites that interact to regulate basal level expression in some cell types. A perfect binding motif for transcription factor Sp1 (CCCCGCCCC) is located at nucleotides -114 to -106 relative to the site of transcriptional initiation, binds strongly to purified Sp1 protein, and forms several complexes when incubated with nuclear extracts. Only one of these complexes is recognized by Sp1-specific antibody. A new protein-binding motif (GCCCCTCCCC, located at -110 to -100) partially overlaps with the Sp1 site and analyses by DNase I protection showed that a new protein ("NF-ODC1") and the Sp1-like proteins interact with the ODC promoter in a mutually exclusive manner. Mutation of the NF-ODC1 binding motif strongly enhanced ODC promoter strength in some cell types, but had little or no influence in others. The effect of mutating the Sp1 site also varied with cell type. These cell type specificities did not correlate with the levels of Sp1 and NF-ODC1 binding activities in nuclear extracts. These results show that regulation of the ODC promoter by the Sp1 family is cell type-specific and modulated by a negative effector that we have termed NF-ODC1.

Impact of mammary grafts on coronary bypass operative mortality and morbidity. Department of Veterans Affairs Cardiac Surgeons

The internal mammary artery is frequently used as a coronary artery bypass graft conduit because of superior long-term patency. The purpose of this study was to determine if there was also an advantage to the internal mammary artery in terms of operative mortality and morbidity. The Department of Veterans Affairs Cardiac Surgery Database was reviewed for two separate time periods, April 1987 through March 1989 and October 1990 through September 1991. During these periods, 14,172 patients underwent coronary artery bypass grafting. Univariate and multivariate logistic regression analyses were used to determine preoperative variables predictive of operative mortality and morbidity, with the independent variable of use of the internal mammary artery added to previously determined indicators. The total group was analyzed in risk quartiles according to expected mortality. Univariate analysis revealed an operative mortality of 6.8% in the early period and 6.5% in the latter period for the saphenous vein groups compared with 3.7% and 3.2%, respectively, for the internal mammary artery groups (p = 0.000). Multivariate analysis revealed an odds ratio of operative death with use of the internal mammary artery graft versus use of vein grafts of 0.78 during the first period and 0.72 during the second period, reductions of 22% and 28%, respectively. There were 29% and 37% reductions in the odds of operative mortality in the highest-risk quartile group of patients using the internal mammary artery graft. The odds ratio of developing mediastinitis with one internal mammary artery graft was 1.84 (p < 0.01) in the first time period and 1.11 in the second time period (p = not significant). However, with multiple mammary bypass grafts, the odds ratios were 3.70 (p < 0.01) and 2.96 (p < 0.01) in the respective time periods. On the basis of this study, it is concluded that internal mammary artery grafts in addition to providing superior long-term patency also decreased operative mortality after adjustment for patient risk factors. Use of the mammary artery does not consistently increase operative complications with the exception of mediastinitis when both internal mammary arteries are employed.

Evidence for excitatory amino acid neurotransmitters in forward and feedback corticocortical pathways within rat visual cortex

It is a commonly accepted notion that cells which make projections between the multiple cortical areas found in the mammalian visual system are excitatory, but there is little direct evidence that this is the case. Here we demonstrate using retrograde tracing with D-[3H]aspartate that connections in the rat which project from lower to higher visual areas (i.e. forward) and those which project from higher to lower areas (i.e. feedback) may use excitatory amino acid neurotransmitters. Following injection into the primary visual cortex, clusters of retrogradely labelled cells were found in several extrastriate areas within the cytoarchitectonic subdivisions 18a ('areas' LM, AL, PX, FLX, RL, AX) and 18b ('area' MX), and in the retrosplenial cortex. In all of these areas D-[3H]aspartate-labelled cells were surrounded by diffuse label which may represent anterograde labelling of axon terminals. This suggests that both legs of reciprocal intracortical circuits have similar chemospecificity. To directly demonstrate excitatory amino acid localization in forward projections, D-[3H]aspartate was injected into extrastriate area LM. As expected, the results revealed retrogradely labelled neurons within area 17. Outside area 17, LM injections labelled neurons in AL, PX, FLX, RL, AX and MX. Taken in the context of the hierarchy of areas in rat cerebral cortex (Coogan and Burkhalter, J. Neurosci., 13, 3749-3772, 1993), these results show that D-[3H]aspartate labels: (1) forward connections from area 17 to LM, AL, PX, RL, AX and MX, (2) feedback connections from LM, AL, FLX, PX, RL, AX and MX to area 17, (3) feedback connections from AL, PX, RL, AX and MX to LM, and (4) lateral connections between FLX and LM. These findings strongly indicate that both forward and feedback connections as well as lateral connections at several different levels of the cortical hierarchy use excitatory amino acid neurotransmitters.

Factors predictive of operative mortality among coronary artery bypass subsets

As risk-adjusted outcome is increasingly being used to make clinical decisions and to assess and improve quality of care, it is important to develop simple, stable models for predicting outcome. Here we address the hypothesis that a risk factor for increased operative mortality at coronary artery bypass grafting may have differential effects in subgroups of patients defined by the presence or absence of other risk variables. We used a series of univariate and multivariate analyses to identify a group of ten patient-related preoperative characteristics independently predictive of operative death in the total population of 12,712 patients undergoing coronary artery bypass grafting at 43 Department of Veterans Affairs medical centers participating in the Department of Veterans Affairs Continuous Improvement in Cardiac Surgery Study. Separate logistic regression models were then developed for each of 14 clinically important subgroups defined by the presence or absence of seven risk variables. Odds ratios for operative death and estimated operative mortality were calculated from these subgroup regression models. Of 65 comparisons of pairs odds ratios of preoperative risk variables between the subgroups with and without a second risk variable, only five were found to be significant (p < 0.05 without adjustment for multiple comparisons); this is only slightly more than would be expected by chance alone. Risk factors for increased operative death appear to have similar odds ratios for subgroups of patients defined by a second risk variable. This finding greatly simplifies the use of predicted operative mortality in clinical decision making and quality assessment and improvement in coronary artery bypass grafting.

Visualization of dendritic morphology of cortical projection neurons by retrograde axonal tracing

Currently there is no reliable retrograde tracing technique for visualization of dendritic morphologies of projection neurons. Here we describe a simple and efficient method that can be used to label neurons in Golgi-like fashion. The approach relies on activity-dependent uptake of tracer. For this purpose we inject the glutamate receptor agonist N-methyl-D,L-aspartic acid (NMDA) at the tracer injection site to massively stimulate neurons and to thereby promote uptake of biocytin or biotinylated dextran amine (BDA) by axon terminals. The results show that co-injections of NMDA/biocytin and NMDA/BDA into the extrastriate lateromedial area (LM) of rat visual cortex labels large numbers of neurons in area 17 in Golgi-like fashion. Similarly injections of the lateral geniculate nucleus (LGN) lead to Golgi-like labeling of corticogeniculate neurons in area 17. The distribution of labeled neurons is highly topographic. In addition the method allows excellent preservation of ultrastructure, indicating that this approach is useful for determining the organization of neuronal circuits within the central nervous system.

Partial mastectomy and breast reduction as a valuable treatment option for patients with macromastia and carcinoma of the breast

The essential goals of every reconstructive procedure of the breast are to create a breast mound and establish symmetry. Breast conservation operation is now a widely accepted treatment for carcinoma of the breast. Four patients who presented with macromastia or mammary hypertrophy and a simultaneous carcinoma of the breast were treated by combined partial mastectomy and bilateral breast reduction. Incisions on the breast were made using standard Wise pattern (keyhole) markings. In each instance, the tumor was removed with a generous margin of normal surrounding mammary tissue. Two procedures used the inferior pedicle technique and two were done by resection and transplantation of the nipple. The average mammary tissue resection was 825 grams. All incisions healed primarily and necessary adjuvant chemoradiation was not delayed. Each patient is alive and well without evidence of disease with a follow-up period ranging from seven to 43 months. Postoperatively, the appearance of the breast is esthetically improved and all symptoms related to macromastia have resolved. Advantages of combining these two techniques include improved symmetry, easier postoperative self-examination of the breast and decreased radiation effect noted with larger breasts. Postoperative mammograms have been useful for patient follow-up evaluation. Combined segmental mastectomy and breast reduction represents a valuable treatment option for the patient who presents with macromastia and carcinoma of the breast. The carcinoma ablative procedure is not compromised and the improved symmetry of the breast has resulted in an excellent cosmetic outcome in these patients.

Evidence for excitatory amino acid neurotransmitters in the geniculo-cortical pathway and local projections within rat primary visual cortex

To examine the organization of axon collaterals of neurons that selectively take up and transport excitatory amino acids, we have used retrograde tracing with D-[3H]Aspartate after injections into different layers of rat primary visual cortex. The results show cells in the lateral geniculate nucleus retrogradely labeled from the cortex. Additional topographically precise input to the thalamic recipient layer 4 originates from neurons in the visual cortex lying in layers 2/3, 5 and 6. These inputs are reciprocated by point-to-point projections from layer 4. Layer 2/3 cells project to layers 5 and 6 in columnar fashion. Putative excitatory input to layer 2/3 originates from a vertical column of cells in layer 5 and the middle of layer 6. In addition layer 2/3 receives input via horizontal collaterals of topographically distant upper layer neurons, from more widespread projections in lower layer 6, and from very widespread projections of cells at the layer 5/6 border. Cells in the depth of layer 5 also distribute collaterals within layers 5 and 6. Our findings provide anatomical evidence that the geniculo-cortical pathway in the mammalian visual system may use excitatory amino acid transmitters. In addition, the results support the notion that most long range connections that link distant points of the topographic map are excitatory.

Regulation of expression of proteinase inhibitor genes by methyl jasmonate and jasmonic Acid

Gel electrophoretic analysis of the proteinase inhibitor proteins induced in tomato leaves by airborne methyl jasmonate (EE Farmer, CA Ryan [1990] Proc Natl Acad Sci USA 87: 7713-7716) revealed the new appearance of inhibitors I and II and two other, higher molecular mass proteins (63.5 and 87 kilodaltons). Northern analysis of methyl jasmonate-induced inhibitors I and II mRNAs in tomato (Lycopersicon esculentum) leaves, and of alfalfa trypsin inhibitor (a Bowman-Birk family inhibitor) mRNA in alfalfa (Medicago sativa) leaves, indicated that nascent inhibitor mRNAs were regulated in a manner similar to wounding, that is, at the transcriptional level. In tobacco (Nicotiana tabacum), transformed with a fused gene composed of the 5' and 3' regions of a wound-inducible potato inhibitor II and a chloramphenicol acetyl transferase (CAT) gene coding region, CAT activity was induced in leaves by methyl jasmonate, consistent with a transcriptional regulation of the inhibitor II gene. In tomato leaves, inhibitor I and II mRNAs and proteins accumulated in leaves distal to those exposed to methyl jasmonate or jasmonic acid to similar levels as in exposed leaves. We suggest that in response to wound signals generated by insect or pathogen attacks, linolenic acid is released into the cytoplasm from plant cell membrane lipids and is rapidly converted in cells to jasmonic acid (or perhaps a closely related derivative such as methyl jasmonate), which serves as a signal to regulate the expression of proteinase inhibitor genes.

Bonding of plastic teeth to denture base resins

This study evaluated the bond strengths of some new and traditional resin denture teeth and denture base resins. It included regular monolithic acrylic resin teeth (Bioform), monolithic acrylic resin-IPN teeth (Bioform IPN), and multilithic acrylic resin-composite resin teeth (Vivosit), with relatively new light-activated resin (Triad), conventional heat-cured resin (Lucitone 199), and autopolymerizing resin (Hygenic) denture base materials. The results of four-point flexure testing showed that the traditional materials gave the highest bond strength values. The autopolymerizing resin systems demonstrated interfacial failure with all resin denture teeth, showing that the common practice of treating teeth with the respective autopolymerizing monomer failed to produce adequate bond strength. Combinations of acrylic resin, IPN, and multilithic denture teeth with light-activated resins gave results calling for improvements in basic bonding system design, since interface debonding was prevalent. No failures occurred between the lap-ridge region of the multilithic tooth system and conventional heat-cured denture base resin.