Bow-and-arrow, technology of the first modern humans in Europe 54,000 years ago at Mandrin, France

Consensus in archaeology has posited that mechanically propelled weapons, such as bow-and-arrow or spear-thrower-and-dart combinations, appeared abruptly in the Eurasian record with the arrival of anatomically and behaviorally modern humans and the Upper Paleolithic (UP) after 45,000 to 42,000 years (ka) ago, while evidence for weapon use during the preceding Middle Paleolithic (MP) in Eurasia remains sparse. The ballistic features of MP points suggest that they were used on hand-cast spears, whereas UP lithic weapons are focused on microlithic technologies commonly interpreted as mechanically propelled projectiles, a crucial innovation distinguishing UP societies from preceding ones. Here, we present the earliest evidence for mechanically propelled projectile technology in Eurasia from Layer E of Grotte Mandrin 54 ka ago in Mediterranean France, demonstrated via use-wear and impact damage analyses. These technologies, associated with the oldest modern human remains currently known from Europe, represent the technical background of these populations during their first incursion into the continent.

Modern human incursion into Neanderthal territories 54,000 years ago at Mandrin, France

Determining the extent of overlap between modern humans and other hominins in Eurasia, such as Neanderthals and Denisovans, is fundamental to understanding the nature of their interactions and what led to the disappearance of archaic hominins. Apart from a possible sporadic pulse recorded in Greece during the Middle Pleistocene, the first settlements of modern humans in Europe have been constrained to ~45,000 to 43,000 years ago. Here, we report hominin fossils from Grotte Mandrin in France that reveal the earliest known presence of modern humans in Europe between 56,800 and 51,700 years ago. This early modern human incursion in the Rhône Valley is associated with technologies unknown in any industry of that age outside Africa or the Levant. Mandrin documents the first alternating occupation of Neanderthals and modern humans, with a modern human fossil and associated Neronian lithic industry found stratigraphically between layers containing Neanderthal remains associated with Mousterian industries.

Human burials at the Kisese II rockshelter, Tanzania

OBJECTIVES

The Late Pleistocene and early Holocene in eastern Africa are associated with complex evolutionary and demographic processes that contributed to the population variability observed in the region today. However, there are relatively few human skeletal remains from this time period. Here we describe six individuals from the Kisese II rockshelter in Tanzania that were excavated in 1956, present a radiocarbon date for one of the individuals, and compare craniodental morphological diversity among eastern African populations.

MATERIALS AND METHODS

This study used standard biometric analyses to assess the age, sex, and stature of the Kisese II individuals. Eastern African craniodental morphological variation was assessed using measures of dental size and a subset of Howells' cranial measurements for the Kisese II individuals as well as early Holocene, early pastoralist, Pastoral Neolithic, and modern African individuals.

RESULTS

Our results suggest a minimum of six individuals from the Kisese II collections with two adults and four juveniles. While the dating for most of the burials is uncertain, one individual is directly radiocarbon dated to ~7.1 ka indicating that at least one burial is early Holocene in age. Craniodental metric comparisons indicate that the Kisese II individuals extend the amount of human morphological diversity among Holocene eastern Africans.

CONCLUSIONS

Our findings contribute to a growing body of evidence that Late Pleistocene and early Holocene eastern Africans exhibited relatively high amounts of morphological diversity. However, the Kisese II individuals suggest morphological similarity at localized sites potentially supporting increased regionalization during the early Holocene.

Middle and Later Stone Age chronology of Kisese II rockshelter (UNESCO World Heritage Kondoa Rock-Art Sites), Tanzania

The archaeology of East Africa during the last ~65,000 years plays a central role in debates about the origins and dispersal of modern humans, Homo sapiens. Despite the historical importance of the region to these discussions, reliable chronologies for the nature, tempo, and timing of human behavioral changes seen among Middle Stone Age (MSA) and Later Stone Age (LSA) archaeological assemblages are sparse. The Kisese II rockshelter in the Kondoa region of Tanzania, originally excavated in 1956, preserves a ≥ 6-m-thick archaeological succession that spans the MSA/LSA transition, with lithic artifacts such as Levallois and bladelet cores and backed microliths, the recurrent use of red ochre, and >5,000 ostrich eggshell beads and bead fragments. Twenty-nine radiocarbon dates on ostrich eggshell carbonate make Kisese II one of the most robust chronological sequences for understanding archaeological change over the last ~47,000 years in East Africa. In particular, ostrich eggshell beads and backed microliths appear by 46-42 ka cal BP and occur throughout overlying Late Pleistocene and Holocene strata. Changes in lithic technology suggest an MSA/LSA transition that began 39-34.3 ka, with typical LSA technologies in place by the Last Glacial Maximum. The timing of these changes demonstrates the time-transgressive nature of behavioral innovations often linked to the origins of modern humans, even within a single region of Africa.

Assessing the Relationship between Vitamin D Status and Impairments in Cognitive and Physical Performance in Older Adults Using a Dual Task Physical Performance Test

BACKGROUND

Vitamin D deficiency has been associated with an increased risk of falls in older adults. Several studies have demonstrated an association between vitamin D deficiency and gait and cognitive impairments, which are two risk factors for falls in the elderly. There is lack of research about the role of vitamin D in cognitive function in the context of mobility.

OBJECTIVE

The purpose of this study was to evaluate the association between vitamin D status with the age-related changes in mobility through higher order cognitive function using a dual task physical performance test.

DESIGN

Cross-sectional.

SETTING

Community-dwelling older adult population located in Miami, Fl.

PARTICIPANTS

Healthy participants over the age of 55 (n=97) who participated in the parent interventional study.

MEASUREMENTS

Participants completed assessments that included serum levels of vitamin D, surveys, and dual task physical performance tests. Spearman's correlations, independent t-tests, repeated measures ANOVAs and multiple logistic regressions were used to examine the relationship between vitamin D insufficiency (25-hydroxyvitamin D <30 ng/ml) and sufficiency (≥30 ng/ml) and dual task physical performance variables. The significance level was set at α=0.05.

RESULTS

There were no significant associations between vitamin D insufficiency and gait velocity during either task. Using Spearman correlations, slower single (P=0.011) and dual task counting rates (P=0.006) were significantly associated with vitamin D insufficiency. Independent t-tests showed dual and single task counting rates were significantly lower in the vitamin D insufficient group compared to the sufficient group (P=0.018 and P=0.028, respectively). The results for the ANOVAs indicated that velocities and counting rates were not significantly different by vitamin D status (Wilk's Lambda =0.999; F (1, 95) =.11, P=.740) (Wilk's Lambda =.999, F(1,95)=.13, P=.718). Vitamin D status was not significantly associated with dual task physical performance (defined as the difference in dual and single task) in gait velocity (OR=1.00, 95% CI: 0.98; 1.02, P=0.772) and counting rate (OR=1.684, 95% CI: 0.15; 19.57, P=0.677), when controlling for confounders.

CONCLUSIONS

Since counting backward is a mental tracking task, which is a component of executive function, our results suggest a relationship between vitamin D insufficiency and executive dysfunction. Executive dysfunction has been previously associated with fall risks in the elderly, and it could be a possible mediator between vitamin D and falls. Our data suggest that cognition may play a significant role in vitamin D's influence on falls, while motor function may play a lesser role.

An earlier origin for stone tool making: implications for cognitive evolution and the transition to Homo

The discovery of the earliest known stone tools at Lomekwi 3 (LOM3) from West Turkana, Kenya, dated to 3.3 Ma, raises new questions about the mode and tempo of key adaptations in the hominin lineage. The LOM3 tools date to before the earliest known fossils attributed to Homo at 2.8 Ma. They were made and deposited in a more C3 environment than were the earliest Oldowan tools at 2.6 Ma. Their discovery leads to renewed investigation on the timing of the emergence of human-like manipulative capabilities in early hominins and implications for reconstructing cognition. The LOM3 artefacts form part of an emerging paradigm shift in palaeoanthropology, in which: tool-use and tool-making behaviours are not limited to the genus Homo; cranial, post-cranial and behavioural diversity in early Homo is much wider than previously thought; and these evolutionary changes may not have been direct adaptations to living in savannah grassland environments.This article is part of the themed issue 'Major transitions in human evolution'.

Short-term synaptic plasticity across topographic maps in the electrosensory system

The early pathways underlying the active electric sense of the weakly electric fish Apteronotus leptorhynchus involve three parallel processing streams. An array of tuberous electroreceptors distributed over the skin provides inputs to the electrosensory lateral line lobe (ELL), forming the basis for three topographic maps: LS (lateral segment), CLS (centrolateral segment), and CMS (centromedial segment). In addition, each map receives topographically preserved inputs from a direct feedback pathway. How this feedback contributes to the distinct spatiotemporal filtering properties of ELL pyramidal neurons across maps is not clear. We used an in vitro approach to characterize short-term plasticity (STP) in the direct feedback synapses onto pyramidal neurons in each map. Our findings indicated that the dynamics of STP varied across maps in a manner that was consistent with the temporal filtering properties of pyramidal neurons in vivo. Using a modeling approach, we found that the STP of direct feedback synapses in CMS was best described by a simple facilitation-depression model. On the other hand, STP in LS was best described by synaptic facilitation with a use-dependent recovery rate. These results suggest that differential regulation of overlapping STP processes in feedback pathways can contribute to the functional specialization of topographic sensory maps.

Homoplasmic yeast cells contain no selectable "hidden" mitochondrial alleles

Zygotes of Saccharomyces cerevisiae that are heteroplasmic for mitochondrial alleles produce diploid progeny that are homoplasmic for one allele or the other, judged by the criterion that upon further subcloning they produce daughter cells of only one phenotype or the other. Here we show that when such cells are subjected to strong selection for the missing allele, it cannot be detected, so that it is probably not present in even a single copy.

Aerobic training does not alter CRP in apparently healthy, untrained men

AIM

Regular aerobic exercise may reduce cardiovascular disease (CVD) risk by lowering the concentration of inflammatory markers, such as C-reactive protein (CRP). While studies in diseased populations have shown significant decreases in CRP concentrations with regular aerobic training, little has been conclusively determined regarding the effects of aerobic training on CRP concentrations in apparently healthy, untrained populations. Aim of the study was to examine the effects of a 17-wk half marathon training program (TP) on CRP concentrations, aerobic fitness, and body composition in apparently healthy, untrained men.

METHODS

Twenty men (29.3±1.0 y) enrolled as training subjects (TRN) in a 17-wk half marathon TP. An additional 22 men (27.8±1.4 y) served as controls (CON). Fasting blood samples were taken at four time points over the TP and were analyzed for CRP and interleukin-6 (IL-6) concentrations. Aerobic capacity (VO2max) and body fat percent (BF%) were measured before and after the TP.

RESULTS

No significant post-training changes in CRP (P=0.70) or IL-6 concentrations (P=0.67) were seen in TRN as a result of the TP, despite significant improvements in VO2max (42.2±1.9 ml∙kg-1∙min⁻¹, P<0.0001) and significant reductions in resting heart rate (P=0.004), BF% (P=0.03), and body mass index (BMI, P=0.05). No significant changes in CRP, VO2max, BMI, or BF% were detected in CON over time.

CONCLUSION

Regular aerobic training does not appear to affect CRP concentrations in apparently healthy, untrained men despite significant improvements in bodyweight, BF%, BMI, and VO2max.

Reply to Comment on 'Unconventional gap state of trapped exciton in lead sulphide quantum dots'

This is a reply to a comment on our previously published paper.

Unconventional gap state of trapped exciton in lead sulfide quantum dots

Exciton states in lead selenide (PbSe) and lead sulfide (PbS) quantum dots have been studied extensively. However, relatively less attention has been paid to the states within the quantum dot bandgap. Our experimental results have revealed a single in-gap state which bears confinement dependence yet cannot be explained by dark exciton theory, nor is it a trap state related to quantum dot surface defects as previously observed. A detailed analysis of the temperature dependence of photoluminescence, Stokes shift, absorption and photoinduced absorption indicates the unconventional GS is a new state of a trapped exciton in a QD film. With appropriate design engineering, these trapped excitons might be harvested in solar cells and other optoelectronic devices.

Zebrafish (Danio rerio) gill neuroepithelial cells are sensitive chemoreceptors for environmental CO2

Adult zebrafish exhibit hyperventilatory responses to absolute environmental CO(2) levels as low as 0.13% ( mmHg), more than an order of magnitude lower than the typical arterial levels (40 mmHg) monitored by the mammalian carotid body. The sensory basis underlying the ability of fish to detect and respond to low ambient CO(2) levels is not clear. Here, we show that the neuroepithelial cells (NECs) of the zebrafish gill, known to sense O(2) levels, also respond to low levels of CO(2). An electrophysiological characterization of this response using both current and voltage clamp protocols revealed that for increasing CO(2) levels, a background K(+) channel was inhibited, resulting in a partial pressure-dependent depolarization of the NEC. To elucidate the signalling pathway underlying K(+) channel inhibition, we used immunocytochemistry to show that these NECs express carbonic anhydrase (CA), an enzyme involved in CO(2) sensing in the mammalian carotid body. Further, the NEC response to CO(2) (magnitude of membrane depolarization and time required to achieve maximal response), under conditions of constant pH, was reduced by 50% by the CA-inhibitor acetazolamide. This suggests that the CO(2) detection mechanism involves an intracellular sensor that is responsive to the rate of acidification associated with the hydration of CO(2) and which does not require a change of extracellular pH. Because some cells that were responsive to increasing also responded to hypoxia with membrane depolarization, the present results demonstrate that a subset of the NECs in the zebrafish gill are bimodal sensors of CO(2) and O(2).

The protein kinase Cbeta-selective inhibitor, Enzastaurin (LY317615.HCl), suppresses signaling through the AKT pathway, induces apoptosis, and suppresses growth of human colon cancer and glioblastoma xenografts

Activation of protein kinase Cbeta (PKCbeta) has been repeatedly implicated in tumor-induced angiogenesis. The PKCbeta-selective inhibitor, Enzastaurin (LY317615.HCl), suppresses angiogenesis and was advanced for clinical development based upon this antiangiogenic activity. Activation of PKCbeta has now also been implicated in tumor cell proliferation, apoptosis, and tumor invasiveness. Herein, we show that Enzastaurin has a direct effect on human tumor cells, inducing apoptosis and suppressing the proliferation of cultured tumor cells. Enzastaurin treatment also suppresses the phosphorylation of GSK3betaser9, ribosomal protein S6(S240/244), and AKT(Thr308). Oral dosing with Enzastaurin to yield plasma concentrations similar to those achieved in clinical trials significantly suppresses the growth of human glioblastoma and colon carcinoma xenografts. As in cultured tumor cells, Enzastaurin treatment suppresses the phosphorylation of GSK3beta in these xenograft tumor tissues. Enzastaurin treatment also suppresses GSK3beta phosphorylation to a similar extent in peripheral blood mononuclear cells (PBMCs) from these treated mice. These data show that Enzastaurin has a direct antitumor effect and that Enzastaurin treatment suppresses GSK3beta phosphorylation in both tumor tissue and in PBMCs, suggesting that GSK3beta phosphorylation may serve as a reliable pharmacodynamic marker for Enzastaurin activity. With previously published reports, these data support the notion that Enzastaurin suppresses tumor growth through multiple mechanisms: direct suppression of tumor cell proliferation and the induction of tumor cell death coupled to the indirect effect of suppressing tumor-induced angiogenesis.

The progression of LNCaP human prostate cancer cells to androgen independence involves decreased FOXO3a expression and reduced p27KIP1 promoter transactivation

The progression of human prostate cancer from the initial androgen-dependent phase to androgen independence involves diminished apoptosis and a release from the cell cycle block triggered by androgen ablation therapy. FOXO transcription factors play a central role in promoting expression of proapoptotic and cell cycle regulatory genes (e.g., FasL and p27KIP1). Reduced FOXO function might, therefore, play a role in androgen-independent progression of human prostate cancer. Herein, we show that FOXO function is compromised in androgen-independent prostate cancer cells (LNAI) versus androgen-dependent LNCaP cells. The FOXO3a protein, the most highly expressed FOXO family member in prostate cancer cells, is hyperphosphorylated in LNAI cells. FOXO3a expression is also markedly reduced in these androgen-independent LNAI cells when compared with parental LNCaP cells. Together, reduced FOXO3a expression coupled to FOXO3a hyperphosphorylation would suppress FOXO transcriptional activity. Accordingly, activity of the FOXO-responsive p27KIP1 promoter is reduced 60% in these LNAI cells when compared with LNCaP cells. Moreover, mutation of a conserved FOXO response element suppresses p27KIP1 promoter activity, substantiating a regulatory role for this FOXO response element in p27KIP1 promoter transactivation. Finally, we show that the activity of a distinct FOXO-responsive promoter, the 3X-IRS promoter, is also reduced in LNAI cells. Collectively, these data show that reduced FOXO3a expression coupled to increased FOXO3a phosphorylation coincide with reduced FOXO-responsive promoter activity in androgen-independent LNAI cells when compared with androgen-dependent LNCaP cells. To the extent that this model reflects human disease, these data suggest that FOXO function may be compromised with androgen-independent progression of human prostate cancer.

Polymorphous low-grade adenocarcinoma of the major salivary glands: report of three cases in an unusual location

AIMS

Polymorphous low-grade adenocarcinoma (PLGA) is the second most common type of malignant neoplasm in minor salivary glands. Its origin in major salivary glands is considered exceedingly rare. Herein, we present three cases of de novo PLGA arising in major salivary glands.

METHODS AND RESULTS

Three cases of PLGA were identified in a large series of primary tumours of major salivary glands. We investigated their clinicopathological profiles, including immunohistochemical features. The three patients (two men and one woman) were 51, 65, and 79 years old. The tumours were 20-30 mm large; two were in the parotid gland and one in the submandibular gland. Histologically, all the tumours had a polymorphous architectural pattern showing predominantly solid, tubular, and cribriform features and invasive growth. Papillary areas were observed focally in two tumours and an 'Indian-file' array in one. The tumour cells had a bland cytological appearance and low mitotic count. Two tumours showed perineural invasion. No preexisting pleomorphic adenoma component was identified. In all cases, tumour cells were positive for epithelial markers, S100 protein, and vimentin but negative for alpha-smooth muscle actin, muscle-specific actin, and glial fibrillary acidic protein. Proliferative activities assessed with the Ki67 labelling index were 4.3%, 7.1%, and 7.6%; no p53 overexpression was observed. Two patients had local recurrence, but none had metastasis or died of tumour.

CONCLUSIONS

PLGAs arising in major salivary glands and those in minor salivary glands have similar clinicopathological and immunohistochemical characteristics. It is important to recognize that PLGA can occur ab initio in the major salivary glands, although it is extremely rare.

Autoantibodies and glomerulonephritis in systemic lupus erythematosus

Autoantibody diversification to a variety of autoantigens is a hallmark for systemic autoimmunity. SLE represents a prototype. In this article the roots of the important questions probed by the Kunkel laboratory in SLE research are traced. Data from the recent animal work by the laboratory of Shu Man Fu are summarized to emphasize the importance of further exploration of autoantibody specificities in lupus with a special emphasis on nephritis and to suggest a broader perspective regarding lupus autoantibody reactivities in addition to those against nuclear components.

Hormone replacement therapy after treatment for breast cancer: physicians' attitudes towards randomized trials

PURPOSE

Physician support is required for successful patient recruitment to a large randomized controlled trial (RCT) designed to determine the safety and benefits of short-term hormone replacement therapy (HRT) after breast cancer (BC).

METHODS

A survey was mailed to 1899 Canadian gynaecologists, family physicians, medical, radiation and surgical oncologists to assess willingness to refer patients to an RCT of HRT after BC.

RESULTS

Of 538 physicians, 420 (78%) reported that they would be willing to refer a woman after BC to an RCT of HRT versus placebo. Variables predicting willingness to refer included: support for HRT in well women (p = 0.04) and after BC (p = 0.0001); support for clinical trials (p = 0.0001); ongoing BC trials at the physicians' institution (p = 0.003); currently prescribing HRT to women after BC (p = 0.03); and beneficial results in ongoing RCTs of HRT in well women (p = 0.02).

CONCLUSIONS

An RCT of short-term HRT after BC may be feasible among Canadian physicians.

Blurring of the senses: common cues for distance perception in diverse sensory systems

Distance perception is an essential task of sensory systems. Our visual systems effectively use binocular visual cues to determine an object's distance. Other visual, but monocular, cues are also available for distance perception. Visual contrast and image blur are two such cues [O'Shea et al., 1994. Vis. Res. 34, 1595-1604; O'Shea et al., 1997. Perception 26, 599-612; Mather, 1997. Perception 26, 1147-1158]. We show the effects of combining these cues using a simple psychophysical test. The novelty in our approach is that our exact choice of visual stimuli allows us to show a direct parallel between visual distance perception and distance perception using an entirely different sense, the electric sense of weakly electric fish. We discuss previous work on electrosensory psychophysics [von der Emde et al., 1998. Nature 395, 890-894] and show that cues used for electrosensory distance perception are analogous to visual contrast and blur. We also suggest that analogous cues are involved in auditory distance perception. The utilization of analogous cues implies that these diverse sensory systems perform similar computations for distance perception.

A study of quetiapine: efficacy and tolerability in psychotic adolescents

OBJECTIVE

To study the effectiveness, safety, and tolerability of quetiapine in adolescents with psychotic disorders.

METHODS

This study was an 8-week, open trial using quetiapine with 15 adolescents, ages 13-17 years, mean age 15.1 years, with a diagnosis of a psychotic disorder. Our primary instruments focused on psychotic symptomatology as measured by the Brief Psychiatric Rating Scale (BPRS), Clinical Global Impression (CGI), Positive and Negative Syndrome Scale (PANSS), and the Young Mania Rating Scale (YMRS). Other measures included adverse events, clinical laboratory tests, vital signs, electrocardiogram (ECG), extrapyramidal (EPS) measures, and ophthalmologic examination.

RESULTS

Quetiapine significantly reduced psychotic symptoms as measured by the BPRS, PANSS, YMRS, CGI, and CGI Severity of Illness scale. The average weight gain was 4.1 kg. After correction for expected weight gain, the mean weight gain over the 8-week period was 3.4 kg. Prolactin and cholesterol remained unchanged. Trends were found for a decrease in T4 and an increase in thyroid-stimulating hormone. Common adverse effects were somnolence, agitation, drowsiness, and headache. No significant findings were noted on repeat ECGs, EPS measures, or ophthalmic examination. The final average treatment dose was 467 mg/day (range 300-800 mg/day).

CONCLUSIONS

Quetiapine is suggested to be effective treatment of youths with psychotic disorders and to have a favorable side-effect profile.

Carcinoma ex pleomorphic adenoma: a clinicopathologic review

BACKGROUND

Carcinoma ex pleomorphic adenoma (CXPA) is an aggressive, poorly understood salivary gland malignancy. Misdiagnosis is common, because the residual mixed tumor component may be small, and various carcinoma subtypes are possible.

METHODS

We retrospectively reviewed the medical records of 73 patients with major salivary gland CXPA treated at our institution from 1960 to 1994. Of the 73 patients, 66 had primary tumors and 7 had recurrent tumors; 47 were men, and 26 were women; the mean age was 61 years.

RESULTS

Adenocarcinoma (31 cases) and salivary duct carcinoma (24 cases) were the most common malignant subtypes. All patients were treated surgically, and 32 also had radiation therapy. Of 66 patients with primary tumors, 23% had local recurrence. Metastasis (either initial or delayed) occurred regionally in 56% and distantly in 44%. Thirty-six patients (55%) died of the disease. At 3 years, overall survival was 39% and at 5 years, 30%.

CONCLUSIONS

Important prognostic factors include tumor size, grade, and clinical and pathologic stage. Patients with minimally invasive tumors (<5 mm) should do well with appropriate surgical treatment.

A comparison of Hispanic and African-American sexually abused girls and their families

OBJECTIVE

To study the differential effects of sexual abuse on Hispanic (HN) and African-American (AA) girls.

METHOD

Sexually abused girls and their caretakers (N = 159), of which 52% (n = 82) were AA (mean age 9.8 years, SD = 3.4, R = 6-17) and 48% (n = 77) were HN (mean age 10.1 years, SD = 3.8, R = 6-18), were included in the study. The mother/caretaker was administered a demographic form, the Achenbach's Child Behavior Checklist (CBCL), and the Family Assessment Measure (FAM-P). The child completed the FAM-C and the Trauma Symptom Checklist for Children (TSCC). The clinician completed the Parental Reaction to Incest Disclosure Scale (PRIDS).

RESULTS

HN girls were found to have a greater number of sexually abusive episodes and waited longer to disclose their abuse while AA girls were more likely to have experienced vaginal penetration. The perpetrators of HN girls were older and more likely to be fathers or stepfathers. The mothers/ caretakers of HN girls perceived their children as having significantly more aggressive behavior, anxiety/depression, somatic complaints, internalizing and externalizing behaviors, and had a higher total score on the CBCL than did AA girls. The HN girls were more likely to see their family as dysfunctional with confusion regarding family values and rules. HN mothers/caretakers perceived their families as more conflicted regarding adaptability and family controls.

CONCLUSIONS

HN girls experienced more emotional and behavioral problems, and both HN girls and their mothers/caretakers perceived their families as more disturbed and dysfunctional.

Carcinoma ex pleomorphic adenoma: a clinicopathologic review

BACKGROUND

Carcinoma ex pleomorphic adenoma (CXPA) is an aggressive, poorly understood salivary gland malignancy. Misdiagnosis is common, because the residual mixed tumor component may be small, and various carcinoma subtypes are possible.

METHODS

We retrospectively reviewed the medical records of 73 patients with major salivary gland CXPA treated at our institution from 1960 to 1994. Of the 73 patients, 66 had primary tumors and 7 had recurrent tumors; 47 were men, and 26 were women; the mean age was 61 years.

RESULTS

Adenocarcinoma (31 cases) and salivary duct carcinoma (24 cases) were the most common malignant subtypes. All patients were treated surgically, and 32 also had radiation therapy. Of 66 patients with primary tumors, 23% had local recurrence. Metastasis (either initial or delayed) occurred regionally in 56% and distantly in 44%. Thirty-six patients (55%) died of the disease. At 3 years, overall survival was 39% and at 5 years, 30%.

CONCLUSIONS

Important prognostic factors include tumor size, grade, and clinical and pathologic stage. Patients with minimally invasive tumors (<5 mm) should do well with appropriate surgical treatment.

Carcinoma ex pleomorphic adenoma: pathologic analysis of 73 cases

Pathologic factors of predictive value for carcinoma ex pleomorphic adenoma (CXPA), an aggressive salivary gland malignancy, are poorly defined. Because residual mixed tumor may be relatively inconspicuous and various carcinoma subtypes are encountered, misdiagnosis is common. To describe the pathologic features and identify potential prognostic factors, we retrospectively examined 73 cases of CXPA of the major salivary glands treated at Mayo Clinic. Paraffin section immunostaining for keratins (AE1/AE3, CK7, CK20), epithelial membrane antigen, carcinoembryonic antigen, vimentin, actin, S-100 protein, glial fibrillary acidic protein, and p53 and c-erbB-2 oncoproteins was performed in 69 cases. DNA content and proliferation indices were determined by digital image analysis of Feulgen- and MIB-I-stained sections, retrospectively. Survival was calculated by the Kaplan-Meier method, and prognostic variables were analyzed with the log-rank test. The carcinoma component was predominant in 82% of tumors. Adenocarcinoma not otherwise specified (31 cases) and salivary duct carcinoma (24 cases) were the most frequent histologic subtypes. Sixty-two tumors were high grade (Broders 3 or 4). Residual mixed tumor was extensively hyalinized in 54 cases. Pathologic features significantly associated with overall survival included pathologic stage (P =.009), tumor size (P =.012), grade (P =.005), proportion of carcinoma (P =.004), extent of invasion (P =.002), and proliferation index of carcinoma (P =.03). Of 4 patients with intracapsular (noninvasive) carcinoma, none had an adverse outcome. The immunohistochemical profile of CXPA included positive staining reactions in the malignant component for AE1/AE3 in 97% of cases, CK7 in 94%, epithelial membrane antigen in 86%, carcinoembryonic antigen in 75%, vimentin in 52%, and S-100 protein in 29%. Expression of p53 and c-erbB-2 oncoproteins was detected in 41% and 30% of the carcinomas, respectively, but neither was associated with decreased survival. High-grade salivary adenocarcinoma that is difficult to classify should raise the suspicion of possible CXPA. Intracapsular carcinoma has a benign clinical course. Significant prognostic factors in CXPA include tumor stage, grade, proportion of carcinoma, extent of invasion, and proliferation index.

Neuronal population codes and the perception of object distance in weakly electric fish

Weakly electric fish use an electric sense to navigate and capture prey in the dark. Objects in the surroundings of the fish produce distortions in their self-generated electric field; these distortions form a two-dimensional Gaussian-like electric image on the skin surface. To determine the distance of an object, the peak amplitude and width of its electric image must be estimated. These sensory features are encoded by a neuronal population in the early stages of the electrosensory pathway, but are not represented with classic bell-shaped neuronal tuning curves. In contrast, bell-shaped tuning curves do characterize the neuronal responses to the location of the electric image on the body surface, such that parallel two-dimensional maps of this feature are formed. In the case of such two-dimensional maps, theoretical results suggest that the width of neural tuning should have no effect on the accuracy of a population code. Here we show that although the spatial scale of the electrosensory maps does not affect the accuracy of encoding the body surface location of the electric image, maps with narrower tuning are better for estimating image width and those with wider tuning are better for estimating image amplitude. We quantitatively evaluate a two-step algorithm for distance perception involving the sequential estimation of peak amplitude and width of the electric image. This algorithm is best implemented by two neural maps with different tuning widths. These results suggest that multiple maps of sensory features may be specialized with different tuning widths, for encoding additional sensory features that are not explicitly mapped.

Hypertrophic sustentaculum tali causing a tarsal tunnel syndrome: a case report

A case report of tarsal tunnel syndrome caused by a hypertrophic sustentaculum tali is presented. This is the first reported case secondary to this etiology. Complete resolution of the patient's symptoms has been obtained through resection of the hypertrophic anatomy. The authors also discuss possible etiologies of tarsal tunnel syndrome.

Trends in intussusception-associated hospitalizations and deaths among US infants

CONTEXT

The newly licensed tetravalent rhesus-human reassortant rotavirus vaccine has been withdrawn following reports of intussusception among vaccinated infants.

OBJECTIVE

To describe the epidemiology of intussusception-associated hospitalizations and deaths among US infants.

DESIGN

This retrospective cohort study examined hospital discharge data from the National Hospital Discharge Survey for 1988-1997, Indian Health Service (IHS) for 1980-1997, California for 1990-1997, Indiana for 1994-1998, Georgia for 1997-1998, and MarketScan for 1993-1996, and mortality data from the national multiple cause-of-death data for 1979-1997 and linked birth/infant death data for 1995-1997.

PATIENTS

Infants (<1 year old) with an International Classification of Diseases, Ninth Revision, Clinical Modification code for intussusception (560.0) listed on their hospital discharge or mortality record, respectively.

RESULTS

During 1994-1996, annual rates for intussusception-associated infant hospitalization varied among the data sets, being lowest for the IHS (18 per 100 000; 95% confidence interval [CI] = 9-35 per 100 000) and greatest for the National Hospital Discharge Survey (56 per 100 000; 95% CI = 33-79 per 100 000) data sets. Rates among IHS infants declined from 87 per 100 000 during 1980-1982 to 12 per 100 000 during 1995-1997 (relative risk =7.6, 95% CI = 3.2-18.2). Intussusception-associated hospitalizations were uncommon in the first 2 months of life, peaked from 5 to 7 months old, and showed no consistent seasonality. Intussusception-associated infant mortality rates declined from 6.4 per 1 000 000 live births during 1979-1981 to 2.3 per 1 000 000 live births during 1995-1997 (relative risk = 2.8, 95% CI = 1.8-4.3). Infants whose mothers were <20 years old, nonwhite, unmarried, and had an education level below grade 12 years were at an increased risk for intussusception-associated death.

CONCLUSIONS

Intussusception-associated hospitalization rates varied among the data sets and decreased substantially over time in the IHS data. Although intussusception-associated infant deaths in the United States have declined substantially over the past 2 decades, some deaths seem to be related to reduced access to, or delays in seeking, health care and are potentially preventable.intussusception, hospitalizations, deaths, risk factors, infants.

Child on child sexual abuse: psychological perspectives

OBJECTIVE

This study describes the emotional and behavioral responses of children who have been sexually victimized by juveniles (CC) 17 years of age and younger compared to child victims of adults (CA) 18 years of age and older.

METHOD

A total sample of N = 194 children and adolescents participated in the study, with 26% (n = 51) comprising CC and 74% (n = 143) encompassing CA. The mother/caretaker was administered a demographic form, Achenbach's Child Behavior Checklist (CBCL), and the Family Assessment Measure (FAM-P). The child was given the Family Assessment Measure (FAM-C) and the Trauma Symptom Checklist for Children (TSCC). The clinician completed the Parental Reaction to Incest Disclosure Scale (PRIDS).

RESULTS

No differences were found between the two groups for the type of sexual abuse, penetration, or the use of force. CC were younger and more likely to be males who were abused in a school setting, home, or a relative's home by a sibling or a non-related male. CC endorsed clinically significant sexual preoccupations and manifested borderline clinically significant symptomatology.

CONCLUSIONS

Children victimized by other children manifested elevated levels of emotional and behavioral problems and were not significantly different from those who had been sexually abused by adults.

Ro60 peptides induce antibodies to similar epitopes shared among lupus-related autoantigens

The coexistence of autoantibodies to ribonucleoproteins (RNP) in sera of patients with systemic lupus erythematosus has been attributed to intermolecular determinant spreading among physically associated proteins. Recently, we showed that murine Ab responses to rRo60 or Ro60 peptides were diversified unexpectedly to small nuclear RNP. In this investigation, the mechanisms for this autoantibody diversification were examined. Intramolecular determinant spreading was demonstrated in mice immunized with human or mouse Ro60316-335. Immune sera depleted of anti-peptide Ab immunoprecipitated Ro60-associated mY1 and mY3 RNA and remained reactive to a determinant on Ro60128-285. Absorption with the immunogen depleted the immune sera completely of anti-Golgi complex Ab (inducible only with human Ro60316-335) and anti-La Ab, and reduced substantially Ab to SmD and 70-kDa U1RNP. Mouse rRo60 completely inhibited the immune sera reactivity to La, SmD, and 70-kDa U1RNP. However, La, SmD, and 70-kDa U1RNP preferentially inhibited the antiserum reactivities to these Ags, respectively. Affinity-purified anti-La Ab were reactive with Ro60, La, SmD, and 70-kDa U1RNP. These results provide evidence that a population of the induced autoantibodies recognized determinants shared by these autoantigens. Lack of sequence homology between Ro60316-335 and La, SmD, or 70-kDa U1RNP suggests that these determinants are conformational. Interestingly, similar cross-reactive autoantibodies were found in NZB/NZW F1 sera. Thus, a single molecular mimic may generate Ab to multiple RNP Ags. Furthermore, cross-reactive determinants shared between antigenic systems that are not associated physically (Ro/La RNP and small nuclear RNP) may be important in the generation of autoantibody diversity in systemic lupus erythematosus.

ABC relaxation theory and the factor structure of relaxation states, recalled relaxation activities, dispositions, and motivations

ABC Relaxation Theory proposes 15 psychological relaxation-related states (R-States): Sleepiness, Disengagement, Physical Relaxation, Mental Quiet, Rested/Refreshed, At Ease/At Peace, Energized, Aware, Joy, Thankfulness and Love, Prayerfulness, Childlike Innocence, Awe and Wonder, Mystery, and Timeless/Boundless/Infinite. The present study summarizes the results of 13 separate factor analyses of immediate relaxation-related states, states associated with recalled relaxation activities, relaxation dispositions, and relaxation motivations on a combined sample of 1,904 individuals (group average ages ranged from 28-40 yr.). Four exploratory factor analyses of Smith Relaxation Inventories yielded 15 items that most consistently and exclusively load (generally at least .70) on six replicated factors. These items included happy, joyful, energized, rested, at peace, warm, limp, silent, quiet, dozing, drowsy, prayerful, mystery, distant, and indifferent. Subsequent factor analyses restricted to these items and specifying six factors were performed on 13 different data sets. Each yielded the same six-factor solution: Factor 1: Centered Positive Affect, Factor 2: Sleepiness, Factor 3: Disengagement, Factor 4: Physical Relaxation, Factor 5: Mental Quiet, and Factor 6: Spiritual. Implications for ABC Relaxation Theory are discussed.

Pediatric parotid masses

OBJECTIVE

To evaluate the incidence, types, and treatment outcomes of pediatric parotid lesions.

DESIGN

Retrospective case review, histological tissue review, and literature review.

SETTING

Tertiary care center.

PATIENTS

All patients aged 18 years and younger with parotid masses evaluated and treated at the Mayo Clinic, Rochester, Minn, from January 1, 1970, to December 31, 1997.

RESULTS

Parotid masses were identified in 118 children (60 boys and 58 girls). At diagnosis, the ages of patients were from birth through 18 years, and 72 (61.0%) were aged 10 years and older. An asymptomatic mass was the most common presentation. Forty-three patients (36.4%) had infectious or inflammatory lesions, 56 (47.5%) had benign lesions, and 19 (16.1%) had malignant lesions. The most common benign lesions were pleomorphic adenoma (22.9%) and hemangioma (10.2%). The most common malignant lesions were mucoepidermoid carcinoma (6.8%) and acinic cell carcinoma (3.4%). The most common treatment was total parotidectomy (40.7%). Surgical complications included temporary facial nerve weakness in 22 (18.6%) patients, permanent facial weakness in 11 (9.3%), and permanent paralysis in 2 (1.7%). Pleomorphic adenoma recurred in 4 (14.8%) of 28 patients and mucoepidermoid carcinoma in 3 (37.5%) of 8 patients. One patient with adenoid cystic carcinoma died of the tumor.

CONCLUSIONS

Although pediatric parotid masses are unusual, they can represent a variety of pathological diagnoses, including malignancy. We advocate prompt evaluation and treatment of these masses, and suggest guidelines for their management, based on diagnosis.

Sensory processing and the network mechanisms for reading neuronal population codes

In many neuronal systems, information appears to be represented in the activity of populations of neurons. Such neuronal population codes must also be read out, or interpreted, by downstream networks. Recent studies in both vertebrate and invertebrate systems have begun to elucidate some of the general mechanisms underlying these processes. Directed behaviors, that involve a directional response to a directional sensory input, have been a particularly useful context for these studies because, among other things, their input-output relationship is easily defined and experimentally controlled. We have recently shown that the neuronal network underlying a directed behavior in the medicinal leech utilizes a specific population coding scheme based on a neuronal population vector. A population vector of mechanosensory neuron activity correlates well with behavioral output and the connectivity of the downstream network is well suited for accurately reading out this population code.

Expression of Pax2 and patterning of the chick inner ear

Early regionalized gene expression patterns within the otocyst appear to correlate with and contribute to development of mature otic structures. In the chick, the transcription factor Pax2 becomes restricted to the dorsal and entire medial side of the otocyst by stage 16/17. The dorsal region of the otocyst forms the endolymphatic duct and sac (ED/ES), and the cochlear duct is derived from the ventromedial region. In the mouse, however, Pax2 expression is reported only in the ventromedial and not the dorsal otocyst. In Pax2 null mice, the cochlea is missing or truncated, but vestibular structures differentiate normally. Here we demonstrate that in the chick, the emerging ED/ES express high levels of Pax2 even when the position of the emerging ED is altered with respect to its environment, either by 180 degrees otocyst rotations about the anterior/posterior axis or transplantation of the otocyst into the hindbrain cavity. However, the Pax2 expression pattern is plastic in the rest of the otic epithelium after 180 degrees rotation of the otocyst. Pax2 is upregulated on the medial side (formerly lateral), and downregulated on the lateral side (formerly medial and expressing Pax2) indicating that Pax2 expression is influenced by the environment. Although Pax2 is upregulated in the epithelium after 180 degrees rotations in the region that should form the cochlear duct, cochlear ducts are truncated or absent, and the ED/ES emerge in a new ventrolateral position. Ablation of the hindbrain at the placode or early otic pit stage alters the timing of regionalized Pax2 expression in the otocyst. The resulting otocysts and ears are generally smaller, vestibular structures are abnormal, ED/ES are missing but cochlear ducts are of normal length. The hindbrain and dorsal periotic mesenchyme provide unique trophic and patterning information to the dorsal otocyst. Our results demonstrate that the ED is the earliest structure patterned in the inner ear and that the hindbrain is important for its specification. We also show that, although normal Pax2 expression is required for cochlear duct development, it is downstream of ventral otocyst patterning events.

Intranasal verrucous carcinoma: relationship to inverting papilloma and human papillomavirus

OBJECTIVES

To establish the incidence, appearance, behavior, and appropriate treatment of intranasal verrucous carcinoma and determine its relationship to inverting papilloma and human papillomavirus (HPV).

STUDY DESIGN

Retrospective review of all cases of intranasal verrucous carcinoma seen at the Mayo Clinic from 1960 through May 1996.

METHODS

Retrospective chart review and data collection for age, sex, smoking history, location, association with inverting papilloma, treatment, recurrence, and follow-up. Polymerase chain reaction (PCR) testing for the presence of HPV DNA was performed on all specimens.

RESULTS

Of the 13 patients identified, most presented with nasal obstruction (10) or a noticeable intranasal lesion (8). The maxillary sinus was the extranasal site most often involved. Five patients had verrucous cancer develop in an inverting papilloma, and one had squamous cell carcinoma with the verrucous component (a hybrid tumor). All but one patient underwent surgery as initial treatment; only one patient had preoperative radiation therapy. Surgical procedures ranged from local excision to a craniofacial resection. Follow-up ranged from 2 months to 32 years (mean, 6.5 y). Four patients had a single recurrence and two tumors recurred a second time. No metastases developed and no one died from the tumor. In seven patients (10 specimens), DNA was successfully amplified for PCR testing, and no HPV DNA was detected.

CONCLUSIONS

When verrucous tumors are discovered early, they can be treated effectively with wide local excision. In some cases, a more extensive procedure may be required. A possible role for HPV in the etiology of these tumors was not found.

The cross-cultural applications of the KAIT: case studies with three differentially acculturated women

The Kaufman Adolescent and Adult Intelligence Test (KAIT), introduced in 1993, is a relatively new measure for the assessment of intelligence. Because of the test's theoretical foundation, standardization procedure, test items, and score interpretations, it is assumed to be a culturally sensitive measure. However, there is little supporting clinical or empirical evidence. The present case study examined cross-cultural applications of the KAIT using 3 volunteers from diverse cultural backgrounds with differential levels of American acculturation. In addition to test scores, the participants' impressions of the testing process were measured with the Subjective Units of Distress Scale. Preliminary evidence suggests that the KAIT, like its predecessor, the K-ABC, may be useful when working with culturally diverse people.

Immune responses to Ro60 and its peptides in mice. I. The nature of the immunogen and endogenous autoantigen determine the specificities of the induced autoantibodies

Anti-Ro60 autoantibodies are found in a variety of autoimmune disorders including systemic lupus erythematosus (SLE), Sjögren's syndrome, primary biliary cirrhosis, and active hepatitis. They are the most prevalent autoantibodies in normal individuals and in asymptomatic mothers of infants afflicted with neonatal lupus. In the present study, immune responses to recombinant human Ro60 (rhRo60) and recombinant mouse Ro60 (rmRo60) and selected Ro60 peptides in non-SLE-prone mice were investigated. Multiple T and B cell epitopes were identified in Ro60. Immunizations with either xenogeneic or autologous Ro60 induced autoantibodies to a diverse group of autoantigens. In addition to La and Ro52, proteins in the small nuclear ribonucleoprotein (snRNP) particles such as SmA, SmB, SmD, and 70-kD U1-RNP were unexpectedly identified as targeted antigens. In the studies involving synthetic Ro60 peptides, both human and mouse Ro60316-335 peptides, which differ in three amino acids, were found to contain dominant cross-reactive T cell determinants. Immunizations with these peptides induced autoantibodies to Ro60, La, SmD, and 70-kD U1-RNP without autoantibodies to Ro52, SmA, or SmB. With human Ro60316-335 as the immunogen, additional autoantibodies reactive with the Golgi complex were found. In contrast to the immunodominance of both human and mouse Ro60316-335 peptides, the T cell determinant in human Ro60441-465 was dominant, whereas that in the mouse peptide was cryptic. Immunization with human Ro60441-465 induced primarily anti-peptide Abs. Mouse Ro60441-465 failed to induce an antibody response. These results show that both the nature of the immunogen and the immunogenicity of the related endogenous antigen are important in determining the specificities of the autoantibodies generated. They have significant implications for proposed mechanisms on the generation of complex patterns of autoantibodies to a diverse group of autoantigens in SLE patients.

Representation of touch location by a population of leech sensory neurons

To form accurate representations of the world, sensory systems must accurately encode stimuli in the spike trains of populations of neurons. The nature of such neuronal population codes is beginning to be understood. We characterize the entire sensory system underlying a simple withdrawal reflex in the leech, a bend directed away from the site of a light touch. Our studies show that two different populations of mechanosensory neurons each encode touch information with an accuracy that can more than account for the behavioral output. However, we found that only one of the populations, the P cells, is important for the behavior. The sensory representation of touch location is based on the spike counts in all of the four P cells. Further, fewer than three action potentials in the P cell population, occurring during the first 100 ms of a touch stimulus, may be required to process touch location information to produce the appropriately directed bend.

Verrucous carcinoma of the larynx: a review of 53 patients

BACKGROUND

Verrucous carcinoma of the larynx is a rare laryngeal neoplasm that can be confused with a benign process. Although usually curable at an early stage, it can be locally aggressive if left untreated. We describe our experience with this tumor and make recommendations for diagnosis and treatment.

METHODS

From 1960 through 1990, 53 patients received initial treatment for verrucous carcinoma of the larynx at the Mayo Clinic. We retrospectively reviewed the presentation, diagnosis, treatment, and outcomes in these patients. All cases were confirmed by histologic examination.

RESULTS

All but two patients were men, and most were smokers. Most tumors were found in the glottis, and 72% were T1 lesions at presentation. Six patients had hybrid tumors consisting of conventional squamous cell carcinoma along with the verrucous component. Sixteen patients had lesions that had been diagnosed as benign before they were seen at our institution. Treatment ranged from transoral excision to laryngopharyngectomy. Ten patients experienced recurrence, but only two patients died of the tumor. No pure verrucous lesion metastasized, and overall survival was similar to that of an age- and sex-matched cohort from the Western North Central U.S. white population.

CONCLUSIONS

When discovered early, verrucous carcinoma of the larynx can be treated by local excision with good results; extensive lesions, however, may require more-aggressive procedures. Close communication between the pathologist and the clinician as well as adequate biopsy is essential for diagnosis. Patients with a conventional squamous cell carcinoma coexistent with a verrucous lesion must be treated as if they had invasive squamous cell carcinoma.

Chemotherapy for advanced esthesioneuroblastoma: the Mayo Clinic experience

OBJECTIVE

Esthesioneuroblastoma (olfactory neuroblastoma) is a rare neuroendocrine tumor that arises in the upper nasal cavity from the olfactory epithelium. Little information is available regarding the treatment of these tumors with chemotherapy in the advanced setting. A retrospective review of patients with recurrent esthesioneuroblastoma treated with chemotherapy between 1970 and 1995 at the Mayo Clinic was undertaken to gain more information regarding the efficacy of chemotherapy treatment for these patients.

METHODS

Ten patients were identified using a computerized data base available at this institution. The clinical and pathological materials, when available, were reviewed, and each tumor reviewed was assigned a Hyams' grade.

RESULTS

There were six men and four women, ranging in age from 22 to 74 years, all of whom had assessable Kadish Stage C disease at the time of chemotherapy treatment. The chemotherapy regimens and clinical follow-up varied during this 25-year time span. The only tumor regression resultant from chemotherapy was observed in patients with high-grade tumors. Two of four patients with high-grade tumors obtained regression from first-line, platinum-based chemotherapy, with a mean duration of regression of 9.3 months (range, 2-13 mo). Survival time from initial diagnosis was 139.5 months (range, 83-168 mo) in patients with low-grade tumors and 32.2 months (range, 5-84 mo) in patients with high-grade tumors. Survival from initial chemotherapy treatment was 44.5 months (range, 3-130 mo) in patients with low-grade tumors and 26.5 months (range, 2-67 mo) in patients with high-grade tumors.

CONCLUSION

Hyams' grading of esthesioneuroblastoma tumors seems to be important in predicting response to chemotherapy. Despite sensitivity to platinum-based chemotherapy, patients with high-grade tumors in this series had a much more aggressive course than did those with lower-grade tumors. This series suggests that cisplatin-based chemotherapy is active in advanced, high-grade esthesioneuroblastoma and is a reasonable choice in the systemic treatment of these patients.

Quantitative analysis of a directed behavior in the medicinal leech: implications for organizing motor output

The local bend is a directed behavior produced by the leech, Hirudo medicinalis, in response to a light touch. Contraction of longitudinal muscles near the touched location results in a bend directed away from the stimulus. We quantify the relationship between the location of touch around the body perimeter and the behavioral output by using video analysis, muscle tension measurements, and electromyography. On average, the direction of the behavioral output differed from the touch location by <8% of the total body perimeter. We discuss our results in the context of two contrasting behavioral strategies: a Continuous strategy, in which the local bend is directed exactly opposite to stimulus location, and a Categorical strategy, in which there are four distinct bend directions, each elicited by stimuli given in a single quadrant of the body perimeter. To distinguish between these strategies, we delivered two competing stimuli simultaneously. The resulting behavioral output is best described by an average of the effects of each stimulus given alone and thus provides support for the Continuous strategy. We also use a simple model, based on anatomical and physiological data, to predict the responses of the known motor neurons to different stimulus locations. The model shows that the activation of two of the motor neurons (D and V) is inconsistent with a Categorical strategy. However, these neurons are known to be active during the local bend behavior. This result, along with our experimental observations, suggests that the local bend network uses a Continuous strategy to encode stimulus location and produce directed behavioral output.

Combined neck dissection and postoperative radiation therapy in the management of the high-risk neck: a matched-pair analysis

PURPOSE

The purpose of this study was to determine the efficacy of postoperative adjuvant radiation therapy with regard to reducing the rate of recurrence in the neck, cancer-related death, and death from any cause in patients with squamous cell carcinoma of the head and neck region metastatic to neck nodes.

METHODS

This was a retrospective review of patients with pathologically confirmed nodal metastases who underwent neck dissection and postoperative adjuvant radiation therapy for squamous cell carcinoma of the head and neck region. Time to recurrence in the dissected area of the neck, any recurrence in the neck, cancer-related death, and death from any cause were estimated with the Kaplan-Meier method. A matched-pair analysis was performed utilizing a cohort of patients who underwent neck dissection without postoperative radiation therapy. The patients from the two cohorts were matched according to previously reported high-risk features for cancer recurrence and death. Cox hazards models for the matched pairs were used to evaluate the relative risk of subsequent recurrence in the dissected side of the neck, any neck recurrence, cancer-related death, and overall survival.

MATERIALS

The medical records and pathologic slides of 95 consecutive patients with pathologically confirmed nodal metastases from squamous cell carcinoma of the head and neck region who underwent neck dissection and postoperative adjuvant radiation therapy between January 1974 and December 1990 were reviewed. Previously published data from 284 patients with squamous cell carcinoma of the head and neck region treated with neck dissection alone between January 1970 and December 1980 were used for a matched-pair analysis.

RESULTS

The relative risks for recurrence in the dissected side of the neck, any neck recurrence (dissected neck or delayed undissected neck metastasis), cancer-related death, and death from any cause for patients treated with operation alone relative to those treated with operation and postoperative radiation were 5.82, 4.72, 2.21, and 1.67, respectively.

CONCLUSION

This study provides evidence that postoperative adjuvant radiation therapy for the high-risk neck can reduce the rate of recurrence within a dissected neck, delayed metastasis within an undissected neck, cancer-related death, and death from any cause.

Use of antipsychotic drugs in nursing homes: current compliance with OBRA regulations

OBJECTIVE

To examine the degree and patterns of compliance with the Omnibus Budget Reconciliation Act (OBRA) regulations regarding the use of antipsychotic drugs in nursing homes.

DESIGN

Retrospective chart review of all resident records.

PARTICIPANTS

Eight nursing homes: five community, two county-owned, and one university-affiliated Veterans Administration facility.

MEASUREMENTS

A structured assessment instrument to track compliance with each aspect of the OBRA regulations regarding antipsychotic drug use.

RESULTS

A total of 1573 nursing home residents' pharmacy records were reviewed between August 1994 and March 1996. Two hundred seventy-nine residents were actively taking antipsychotic medications (prevalence = 17.7%). Mean compliance greater than 70% was found for (1) appropriate diagnostic indication (mean = 70.9%), (2) dosage within recommended limits (mean = 90.1%), and 3) documented appropriate target symptoms (mean = 90.4%). Dosages were more likely to exceed limits in those patients with histories of major mental illness, particularly schizophrenia.

CONCLUSIONS

Nursing homes were better able to comply with those guidelines that are most specific. Educational interventions now need to focus on behavioral interventions, monitoring of adverse effects, and efficacy. These data are useful in establishing threshold levels of performance and can be used by nursing homes for continuous quality improvement. OBRA continues to impact neuroleptic drug prescribing practices in nursing homes significantly.

A neuronal network for computing population vectors in the leech

The correlation of neuronal activity with sensory input and behavioural output has revealed that information is often encoded in the activity of many neurons across a population, that is, a neural population code is used. The possible algorithms that downstream networks use to read out this population code have been studied by manipulating the activity of a few neurons in a population. We have used this approach to study population coding in a small network underlying the leech local bend, a body bend directed away from a touch stimulus. Because of the small size of this network we are able to monitor and manipulate the complete set of sensory inputs to the network. We show here that the population vector formed by the spike counts of the active mechanosensory neurons is well correlated with bend direction. A model based on the known connectivity of the identified neurons in the local bend network can account for our experimental results, and is suitable for reading out the neural population vector. Thus, for the first time to our knowledge, it is possible to link a proposed algorithm for neural population coding with synaptic and network mechanisms in an experimental system.

Damage-sensing mechanisms in human cells after ionizing radiation

Human cells have evolved several mechanisms for responding to damage created by ionizing radiation. Some of these responses involve the activation or suppression of the transcriptional machinery. Other responses involve the downregulation of enzymes, such as topoisomerase I, which appear to be necessary for DNA repair or apoptosis. Over the past five years, many studies have established links between DNA damage, activation of transcription factors that are coupled to DNA repair mechanisms, increased gene transcription and altered cell cycle regulation to allow for repair or cell death via apoptosis or necrosis. Together these factors determine whether a cell will survive with or without carcinogenic consequences. The immediate responses of human cells to ionizing radiation, in terms of sensing and responding to damage, are therefore, critical determinants of cell survival and carcinogenesis.

Angiosarcomas of the head and neck: clinical and pathologic characteristics

Between 1974 and 1992, 32 patients with pathologically diagnosed angiosarcoma of the head and neck were evaluated at our institution. The primary treatment group consisted of 24 patients who had the initial diagnosis made or confirmed at our institution, and the other 8 patients formed the salvage group. There were 23 men and 9 women. The median age in the primary treatment group was 63 years (range 18 to 91 years). The overall median survival among the primary group patients was 4.8 years, and the 3-year survival was estimated to be 57% (95% confidence interval 39% to 84%). The median follow-up was 2.1 years (range 83 days to 9.7 years). Patients who had tumors less than 7.0 cm in diameter and tumors with invasion only to the subcutaneous tissues had better overall survival and longer time to first adverse event. Diploid DNA content was a significant favorable prognostic factor for time to first adverse event. Mitotic activity was of borderline significance with both end points. Patients who had tumors of less than 1.5 cm were treated successfully with surgery alone. Patients treated with combined surgery and radiotherapy also tended to do better. Because most patients in whom regional recurrences developed had tumors larger than 7.0 cm, we conclude that patients with tumors of this size may benefit from regional neck node dissection at the time of primary excision or from elective neck irradiation.