Developmental regulation of neural cell adhesion molecule in human prefrontal cortex.

Neural cell adhesion molecule (NCAM) is a membrane-bound cell recognition molecule that exerts important functions in normal neurodevelopment including cell migration, neurite outgrowth, axon fasciculation, and synaptic plasticity. Alternative splicing of NCAM mRNA generates three main protein isoforms: NCAM-180, -140, and -120. Ectodomain shedding of NCAM isoforms can produce an extracellular 105-115 kilodalton soluble neural cell adhesion molecule fragment (NCAM-EC) and a smaller intracellular cytoplasmic fragment (NCAM-IC). NCAM also undergoes a unique post-translational modification in brain by the addition of polysialic acid (PSA)-NCAM. Interestingly, both PSA-NCAM and NCAM-EC have been implicated in the pathophysiology of schizophrenia. The developmental expression patterns of the main NCAM isoforms and PSA-NCAM have been described in rodent brain, but no studies have examined NCAM expression across human cortical development. Western blotting was used to quantify NCAM in human postmortem prefrontal cortex in 42 individuals ranging in age from mid-gestation to early adulthood. Each NCAM isoform (NCAM-180, -140, and -120), post-translational modification (PSA-NCAM) and cleavage fragment (NCAM-EC and NCAM-IC) demonstrated developmental regulation in frontal cortex. NCAM-180, -140, and -120, as well as PSA-NCAM, and NCAM-IC all showed strong developmental regulation during fetal and early postnatal ages, consistent with their identified roles in axon growth and plasticity. NCAM-EC demonstrated a more gradual increase from the early postnatal period to reach a plateau by early adolescence, potentially implicating involvement in later developmental processes. In summary, this study implicates the major NCAM isoforms, PSA-NCAM and proteolytically cleaved NCAM in pre- and postnatal development of the human prefrontal cortex. These data provide new insights on human cortical development and also provide a basis for how altered NCAM signaling during specific developmental intervals could affect synaptic connectivity and circuit formation, and thereby contribute to neurodevelopmental disorders.

Synaptophysin and postsynaptic density protein 95 in the human prefrontal cortex from mid-gestation into early adulthood.

Previous studies of postnatal synaptic development in human frontal cortex have shown that synaptic density rises after birth, reaches a plateau in childhood and then decreases to adult levels by late adolescence. A similar pattern has been seen in nonhuman primate cortex. These earlier studies in human cortex are limited, however, by significant age gaps in study subjects at critical inflection points of the developmental curve. Additionally, it is unclear if synaptic development occurs in different patterns in different cortical layers in prefrontal cortex (PFC). The purpose of this study was to examine synaptic density in human PFC across development by measuring two synaptic marker proteins: synaptophysin (presynaptic), and postsynaptic density protein 95 (PSD-95; postsynaptic). Western blotting was used to assess the relative levels of synaptophysin and PSD-95 in dorsolateral PFC of 42 subjects, distributed in age from 18 weeks gestation to 25 years. In addition, synaptophysin immunoreactivity was examined in each layer of areas 9 and 46 of PFC in 24 subjects, ranging in age from 0.1-25 years. Synaptophysin levels slowly increased from birth until age 5 and then increased more rapidly to peak in late childhood around age 10. Synaptophysin subsequently decreased until the adult level was reached by mid-adolescence, around age 16. PSD-95 levels increased postnatally to reach a stable plateau by early childhood with a slight reduction in late adolescence and early adulthood. The pattern of synaptophysin immunoreactivity seen with immunohistochemistry was similar to the Western experiments but the changes across age were more subtle, with little change by layer within and across age. The developmental patterns exhibited by these synaptic marker proteins expand upon previous studies of developmental synaptic changes in human frontal cortex; synaptic density increases steadily from birth to late childhood, then decreases in early adolescence to reach adult levels by late adolescence.

Pregnancy and informed consent to research.

Federal regulations governing research with human subjects have limited a pregnant woman's authority to decide to participate in research since 1975 by requiring the consent of the fetus's father. Recognition of pregnant women's legal rights has increased since then, in particular, their right to be treated no differently from other adults. In 1998 the Department of Health and Human Services proposed amendments to these regulations that recognize women as the sole decision makers in this area and eliminate requirements for paternal consent. These regulations have not been adopted, however.

Perioperative myocardial ischemia in cataract surgery patients: general versus local anesthesia.

Patients having cataract surgery are usually elderly and have risk factors for ischemic heart disease. We sought to determine the incidence of perioperative myocardial ischemia in patients having cataract surgery and compare the influence of local anesthesia (LA) and general anesthesia (GA). Eighty-one patients undergoing cataract surgery with at least two risk factors for ischemic heart disease were monitored continuously for 24 h by using electrocardiogram leads II and V5 and a Holter recorder (Medilog 4500, Oxford Ltd, UK). Patients were randomly allocated to two groups, either LA (n = 39) or GA (n = 42). In the LA group, a peribulbar block was performed, whereas a similar block was performed in the GA group after tracheal intubation. The study demonstrated that cataract patients suffered from a frequent incidence of perioperative myocardial ischemia (31%). There was no difference in the incidence rate between the groups: 12 of 39 in the LA group and 13 of 42 in the GA group (P: = NS). However, the number of ischemic episodes was significantly increased in the GA group (18 vs. 13 in the LA group) (P<0.05), and there were significantly more intraoperatively in the GA group (8 vs. 1) (P<0.01). All intraoperative ischemic events were associated with tachycardia (> or =20% of baseline), whereas postoperative ischemic changes were mostly independent of heart rate. Only one of the ischemic patients (in the GA group) was admitted as a result of intractable chest pain. There were significantly less intraoperative episodes in the LA group, suggesting that LA may be safer than GA in patients during this type of surgery.

Normal cellular levels of synaptophysin mRNA expression in the prefrontal cortex of subjects with schizophrenia.

BACKGROUND: Previous studies have reported that the 38-kd synaptic vesicle-associated protein, synaptophysin, is decreased in the prefrontal cortex of subjects with schizophrenia. METHODS: To determine whether the decreased protein levels reflect diminished expression of the synaptophysin gene by prefrontal cortex neurons, we used in situ hybridization histochemistry to determine the cellular levels of synaptophysin messenger RNA in prefrontal cortex area 9 from 10 matched pairs of schizophrenic and normal control subjects. RESULTS: Neither the density of neurons with detectable levels of synaptophysin messenger RNA nor the mean level of synaptophysin messenger RNA expression per neuron differed between schizophrenic and control subjects in any cortical layer. CONCLUSIONS: These findings indicate that the expression of synaptophysin messenger RNA is not altered in this brain region in schizophrenia. Consequently, reduced levels of synaptophysin protein in the prefrontal cortex of subjects with schizophrenia are more likely to reflect either posttranscriptional abnormalities of synaptophysin in prefrontal cortex neurons or a diminished number of axonal projections to the prefrontal cortex from other brain regions.

Decreased dendritic spine density on prefrontal cortical pyramidal neurons in schizophrenia.

BACKGROUND: The pathophysiological characteristics of schizophrenia appear to involve altered synaptic connectivity in the dorsolateral prefrontal cortex. Given the central role that layer 3 pyramidal neurons play in corticocortical and thalamocortical connectivity, we hypothesized that the excitatory inputs to these neurons are altered in subjects with schizophrenia. METHODS: To test this hypothesis, we determined the density of dendritic spines, markers of excitatory inputs, on the basilar dendrites of Golgi-impregnated pyramidal neurons in the superficial and deep portions of layer 3 in the dorsolateral prefrontal cortex (area 46) and in layer 3 of the primary visual cortex (area 17) of 15 schizophrenic subjects, 15 normal control subjects, and 15 nonschizophrenic subjects with a psychiatric illness (referred to as psychiatric subjects). RESULTS: There was a significant effect of diagnosis on spine density only for deep layer 3 pyramidal neurons in area 46 (P = .006). In the schizophrenic subjects, spine density on these neurons was decreased by 23% and 16% compared with the normal control (P = .004) and psychiatric (P = .08) subjects, respectively. In contrast, spine density on neurons in superficial layer 3 in area 46 (P = .09) or in area 17 (P = .08) did not significantly differ across the 3 subject groups. Furthermore, spine density on deep layer 3 neurons in area 46 did not significantly (P = .81) differ between psychiatric subjects treated with antipsychotic agents and normal controls. CONCLUSION: This region- and disease-specific decrease in dendritic spine density on dorsolateral prefrontal cortex layer 3 pyramidal cells is consistent with the hypothesis that the number of cortical and/or thalamic excitatory inputs to these neurons is altered in subjects with schizophrenia.

Metoclopramide induced akathisia during cesarean section.

We report a case of akathisia developed after administration of 2.5 mg metoclopramide for treatment of nausea during cesarean section. The relevant literature as well as options for prevention and treatment of this phenomenon are reviewed.

Coronary spasm during outpatient fiberoptic laser bronchoscopy.

A 63-year-old woman with metastatic breast cancer was referred to our bronchoscopy unit for outpatient laser resection of an endobronchial mass through fiberoptic bronchoscopy. The patient had no history of ischemic heart disease. During the procedure, the patient developed an ST-segment elevation and a complete atrioventricular block. IV nitroglycerin and morphine were effective in treating this episode. In this patient, we were able to demonstrate a focal spasm by postbronchoscopy coronary angiography.

Roles of physicians, attorneys, and illness experience in advance directives.

BACKGROUND: Age, illness severity, functional status, and education are associated with advance directive completion. We examined these patient characteristics and discussions with attorneys and physicians in a predictive model for advance directive completion. METHODS: We did a cross-sectional survey of 255 randomly selected patients in a VA outpatient clinic. RESULTS: Patients were predominantly men (95.2%), married (61.9%), with a mean age of 63.2 years; 17.7% of the patients had an advance directive; 5.0% had only a living will, 6.0% had only a durable power of attorney for health care, and 6.7% had both. Age, marital status, illness severity, previous serious illness in spouse, and physician discussion were all associated with advance directive completion in a multiple logistic regression. Eighty-two patients were asked about discussions with attorneys--15 had advance directives; of these, 13 had talked to an attorney, but only 7 had talked to a physician. CONCLUSIONS: Previous serious spousal illness, marital status, age, illness severity, and patient-physician discussions all predicted completions of an advance directive. Attorney discussions were strongly associated with advance directive completion. Better communication between physicians, patients, and attorneys may increase the usefulness of advance directives.

Spontaneous intracerebral hemorrhage in critically ill patients: incidence over six years and associated factors.

OBJECTIVE: Intracerebral hemorrhage (ICH) is associated with a high mortality. The present study sought to determine the incidence of spontaneous ICH in an intensive care unit (ICU) and associated factors. DESIGN: A 6 year retrospective study. SETTING: A general ICU in a university hospital. PATIENTS: All ICU patients developing ICH were included in the study. All trauma and neurosurgical patients were excluded, as well as patients who were admitted to the ICU because of ICH. MEASUREMENTS AND RESULTS: During the study period 3032 patients were hospitalized in the ICU, and 834 were excluded. The remaining 2198 patients comprised the study population. Computed tomography of the head was performed in a total of 227 patients, and the 9 patients found to have new onset ICH comprise the group of interest. None of these patients were hypertensive. Seven of the patients had either a primary hematologic malignancy or bone marrow transplantation. Eight had thrombocytopenia of <100x10(9)/l (median 10x10(9)/l, range 3-150x10(9)/l), and in 6 it preceded ICH by 5 days or more. Only in one patient were both PTT and PT prolonged. All were mechanically ventilated with high peak inspiratory pressure (PIP) (median 37 cm H2O, range 20-43 cm H2O). Arterial carbon dioxide tension (PaCO2) was considerably elevated (median 65 mm Hg, range 41-87 mm Hg). All of the patients had impaired renal and hepatic function (urea: median 14 mmol/l, range 9.9-52 mmol/l; bilirubin: median 94 micromol/l, range 20-360 micromol/l), and five had septicemia. Eight of the patients bled to other sites before they developed ICH. All patients died shortly after the diagnosis of ICH. CONCLUSIONS: Spontaneous nonhypertensive ICH is a rare, fatal event in the ICU. Associated factors include thrombocytopenia, the need for mechanical ventilation, elevated PIP and PaCO2, sepsis, and impaired hepatic and renal function.

Chemotherapy and P-glycoprotein expression in chondrosarcoma.

Chondrosarcomas are alleged to be resistant to chemotherapy. A retrospective review of our experience primarily with dedifferentiated chondrosarcomas treated with chemotherapy was performed to reevaluate the efficacy of chemotherapy for this tumor. There were 18 patients: 14 stage IIB and four stage III. Seventeen patients had dedifferentiated chondrosarcoma. The median age at diagnosis was 57 years. Fourteen of the patients underwent wide excision of the tumor, two underwent amputation, and two had no surgery. The femur and the pelvis were the most common locations of the primary tumor. Chemotherapy for 11 of the patients consisted of cisplatin and doxorubicin. Survival was analyzed with the Kaplan-Meier method; the median survival was 12 months. The hypothesis that chondrosarcomas express P-glycoprotein was tested. Expression of P-glycoprotein was evaluated by immunostaining with use of the C494 and C219 antibodies on 41 benign and malignant cartilage tumors, six of which were from the patients in the chemotherapy group. Immunostaining revealed that 37 of 41 cartilage tumors expressed P-glycoprotein. The rate of survival of patients with high-grade chondrosarcoma treated with chemotherapy is poor. P-glycoprotein expression is common in benign and malignant cartilage lesions. The lack of response to chemotherapy may be related to the expression of P-glycoprotein.

Histologic evidence of a radiosensitizing effect of Taxol in patients with astrocytomas.

The new anticancer agent Taxol appears to potentiate the effects of radiation on brain tumor cell lines in vitro and was recently evaluated by our group as a radiosensitizer in a phase I study for primary brain tumors. In that study, we administered Taxol as a three-hour IV infusion repeated every week for six weeks and gave daily cranial irradiation concurrently for a total of 6000 rads. We reviewed the charts of the 60 patients who participated in the study, and identified twelve patients who underwent a second surgery after treatment because of progressive symptoms and an enlarging intracranial mass on MRI. Pathologically, each patient showed prominent radionecrosis, and other evidence of accelerated radiation changes (confluent areas of coagulative necrosis, bizarre nuclei, marked thickening and fibrinoid changes in multiple blood vessels). These changes were noted many weeks earlier than would be expected after radiation therapy alone and were independent of age, and tumor histology. We postulate that the accelerated radiation changes may be due to the radiation sensitizing effects of Taxol. We also noted a change of the pattern of tumor recurrence, compared to historic reports, and a dose-necrosis relationship where the resected tumor is formed completely of necrotic tissue in patients who received 150 mg/m2 or higher dose of Taxol. These observations may be of significance for future study design.

Unexpected in vitro chemosensitivity of malignant gliomas to 4-hydroxyperoxycyclophosphamide (4-HC).

To individually tailor chemotherapy for patients with malignant gliomas according to tumor chemosensitivity, a rapid assay system which can be performed with a high success rate is needed. The fluorescent cytoprint assay (FCA) can assess multiple chemotherapeutic agents using small (approximately 500 cells) tumor aggregates very quickly (approximately 1 wk). Tissue samples from 51 patients with malignant gliomas obtained either at time of initial diagnosis (n = 34) or at recurrence were assayed using this method. The assay success rate approached 90% in those culture samples which were histologically verified as tumor. A meaningful number of agents could be tested both on samples obtained by stereotactic biopsy (median, 5) and on specimens from more extensive resections (median, 6). One hundred ninety-three FCAs were performed on a samples obtained from 36 patients. In only twenty six assays (14%) was an agent deemed sensitive (> 90% cell kill) to a chemotherapeutic agent. Sixty-two percent of sensitive FCAs were observed in tumors tested against the activated analog of cyclophosphamide, 4-hydroxyperoxycyclophosphamide (4-HC), where a sensitivity rate (# samples sensitive/total tested against agent) of 64% (95 % CI, 36.6-77.9%) was noted. This rate was significantly higher than with any other agent tested (p = 0.012, two sided McNemar's test) and was not affected by age, histology or disease status. We conclude that: (1) the FCA represents a feasible method for quickly assaying tumors for sensitivity to multiple chemotherapeutic agents; and (ii) malignant gliomas may be particularly sensitive to 4-HC.

Cerebrospinal fluid cytology in patients with cancer: minimizing false-negative results.

BACKGROUND: Detection of malignant cells on cytologic examination of the cerebrospinal fluid (CSF) is the diagnostic gold standard for leptomeningeal carcinomatosis. The absence of cells is a primary endpoint for most therapeutic trials. Unfortunately, false-negative results are common. Practical strategies are necessary to remedy this problem. METHODS: Four physician-dependent variables (CSF sample volume, site of CSF sampling, processing time, and frequency of CSF sampling) were identified, and their contributions to the false-negative rate of CSF cytology were evaluated prospectively in 39 patients with leptomeningeal carcinomatosis. Retrospective data were analyzed to estimate the importance of these variables in daily practice. RESULTS: False-negative CSF cytology results correlated with small CSF volume (P < 0.001), delayed processing (P < 0.001), not obtaining CSF from a site of symptomatic or radiographically demonstrated disease (P = 0.02), and sampling fewer than two times (P < 0.001). In 1 year, 97% of CSF specimens at the study institution were of inadequate volume; >25% were processed too slowly. CONCLUSIONS: False-negative CSF cytology results are common, but can be minimized by: 1) withdrawing at least 10.5 mL of CSF for cytologic analysis; 2) processing the CSF specimen immediately; 3) obtaining CSF from a site of known leptomeningeal disease; and 4) repeating this procedure once if the initial cytology is negative.