Organization of auditory cortex in the albino rat: sound frequency

1. Responses of neurons in the auditory cortex of the albino rat were examined using microelectrode mapping techniques. Characteristic frequencies were determined for numerous electrode penetrations across the cortical surface in individual animals. A primary auditory area was identified in the posterolateral neocortex that was characterized by short latency responses to tone bursts and tonotopic organization with high frequencies represented rostrally and low frequencies, caudally. Within this area cells with similar characteristic frequencies were aligned in a dorsoventral orientation to form isofrequency contours. 2. Tuning curves obtained from primary auditory cortex were characteristically "V" shaped with Q10's ranging from 0.97 to 28.4. Maximum Q10 values increased monotonically with characteristic frequency (CF). The lowest thresholds at CF closely approximated the behavioral audiogram for the albino rat. Many neurons, however, had CF thresholds well above the behavioral limit. 3. Areas were found dorsal and ventral to the primary auditory cortex in which CF's were clearly discontinuous with the neighboring isofrequency contours. These data suggest the presence of other auditory fields, the detailed characteristics of which have yet to be examined.     

Associations of place of birth with asthma and wheezing in Mexican American children

BACKGROUND: There are wide global variations in the prevalence of asthma and wheezing. OBJECTIVES: We examined the associations of place of birth with doctor-diagnosed asthma, wheezing in the past 12 months, and other allergic conditions in Mexican American children. METHODS: The study used data on 4121 Mexican American children age 2 months to 16 years who participated in the Third National Health and Nutrition Examination Survey. RESULTS: The risk of asthma was associated with being born in the United States after adjusting for sex, age, history of ear infection, and having a regular place for health care (odds ratio, 2.19; 95% CI, 1.09-4.40). Among children with no previous history of ear infection, US-born children were more likely to report wheezing in the past 12 months than their peers born in Mexico after controlling for confounding variables (odds ratio, 2.05; 95% CI, 1.09-3.87). Mexican American children born in the United States were more likely to have positive skin reaction to cat, house mite, Alternaria alternata , peanut, Bermuda grass, and short ragweed but were less likely to have a positive skin test to German cockroaches after adjusting for sex, age, ear infection, having a regular place for health care, and area of residence. CONCLUSION: Our study indicated significant associations of place of birth with respiratory symptoms and allergic conditions in Mexican American children. These findings highlight the need for further studies to examine environmental factors that change by migration and explain the observed differential in the risk of asthma or wheezing.     

Short-termin vivo stability of endothelial-lined polyester elastomer and polytetrafluoroethylene grafts

A fibronectin substrate will significantly enhance the strength of endothelial cell attachment on grafts constructed of polyester elastomer (PE) and polytetrafluoroethylene (e-PTFE). This experiment was undertaken to determine the short-termin vivo stability of endothellum on these fibronectin coated surfaces. Eight mongrel dogs underwent bilateral carotid artery replacement with both graft materlals. All grafts were inoculated with 2,000 cells/mm² using cultured autogenous venous endothelium labelled with Indium-111-oxine. The Indium-111 label in the grafts was measured immediately prior to implantation, after 1 hour ofin vivo perfusion, and at explantation after 24 hours. The percentage of inoculated cells attached to the grafts before perfusion was simillar for both materials, 93.3±3.0% versus 92.2±7.2%, for PE and e-PTFE respectively. All grafts were patent at one hour after implantation. PE grafts were found to have 93.8±3.9 % of the attached cells present at one hour while e-PTFE grafts had only 54.5 ± 10.8 % remaining, p<.001. After 24 hours, 5/8 (62.5%) e-PTFE grafts and 2/8 (25.0 %) PE grafts remained patent, p=.13. Of the patent grafts however, endothelial cell retention was still superior on the PE grafts with 78.0±0.6% of the attached cells remaining compared to only 24.5±6.1% on e-PTFE, p<.001. Occluded PE grafts had fewer cells remaining at 24 hours than patent ones, 78.0±0.6% versus 31.1±32.8%, respectively, p=.13. Histologically, patent PE grafts demonstrated nearly confluent endothelial monolayers while e-PTFE had patches of endothelial cells surrounded by, a platelet-fibrin carpet. We conclude that short-term patency appears to be determined by the extent of endothelial retention on PE but not e-PTFE.     

Triplications of chromosome 1p36.3, including the genes GABRD and SKI,are associated with a developmental disorder and a facial gestalt

Triplication of chromosomal region 1p36.3 is a rare genomic rearrangement. In this report, we delineate the phenotypic spectrum associated with 1p36.3 triplications. We describe four patients with microtriplications of variable size, but with a strong phenotypic overlap, and compare them to previously described patients with an isolated triplication or duplication of this region. The 1p36.3 triplication syndrome is associated with a distinct phenotype, characterized by global developmental delay, moderate intellectual disability, seizures, behavioral problems, and specific facial dysmorphic features, including ptosis, hypertelorism, and arched eyebrows. The de novo occurrence of these microtriplications demonstrates the reduced reproductive fitness associated with this genotype, in contrast to 1p36.3 duplications which are mostly inherited and can be associated with similar facial features but with a less severe developmental phenotype. The shared triplicated region encompasses four disease-related genes of which GABRD and SKI are most likely to contribute to the phenotype.     

Inducible nitric oxide synthase activity of cloned murine microglial cells

Nitric oxide (NO) is a short-lived diffusable molecule now believed to participate in multiple physiologic functions in the CNS including neurotransmission and the maintenance of vascular tone. Previously, we reported that cell lines obtained by retroviral immortalization of tissue macrophages (M?;) could be induced to synthesize nitrite (NO), a stable end product of the NO synthetic pathway. We have further characterized the induction and activity of this pathway in a panel of seven microglial clones derived from primary embryonic mouse brain cultures. Like M?;, these clones were found to release high levels of NO_-² in response to recombinant interferon-γ (rIFN-γ) as a priming signal together with either bacterial lipopolysaccharide (LPS) or exogenous recombinant tumor necrosis factor-α (rTNF-α). As previously demonstrated for M?;, phagocytosis of zymosan particles during induction of enzyme activity enhanced subsequent NO production, which is of interest in light of the postulated phagocytic role of microglia within the CNS. Biochemical characterization of enzyme activity in intact microglial clones and in isolated cytosolic fractions indicates that the microglial NO synthase present in these murine cell clones represents the M?;-like isotype. These findings suggest that microglial cells could represent a major source of NO within the CNS.     

Abrin Poisoning

Abrin is a toxic protein obtained from the seeds of Abrus precatorius (jequirity bean), which is similar in structure and properties to ricin. Abrin is highly toxic, with an estimated human fatal dose of 0.1–1 µg/kg, and has caused death after accidental and intentional poisoning. Abrin can be extracted from jequirity beans using a relatively simple and cheap procedure. This satisfies one criterion of a potential chemical warfare agent, although the lack of large scale production of jequirity seeds means that quantity is unavailable for ready mass production of abrin for weapons. This contrasts with the huge cultivation of Ricinus seeds for castor oil production. At the cellular level, abrin inhibits protein synthesis, thereby causing cell death. Many of the features observed in abrin poisoning can be explained by abrin-induced endothelial cell damage, which causes an increase in capillary permeability with consequent fluid and protein leakage and tissue oedema (the so-called vascular leak syndrome). Most reported cases of human poisoning involve the ingestion of jequirity beans, which predominantly cause gastrointestinal toxicity. Management is symptomatic and supportive. Experimental studies have shown that vaccination with abrin toxoid may offer some protection against a subsequent abrin challenge, although such an approach is unlikely to be of benefit in a civilian population that in all probability would be unprotected.     

Elevated serum insulin-like growth factor binding protein-2 as a prognostic marker in patients with ovarian cancer.

PURPOSE: The purpose of this research was to examine the diagnostic and prognostic significance of elevated serum insulin-like growth factor binding protein (IGFBP)-2 levels in women with ovarian cancer from diagnosis through treatment to relapse or remission. EXPERIMENTAL DESIGN: Serum collected pre- and postoperatively in women newly diagnosed with ovarian cancer, during adjuvant chemotherapy cycles, at 6 months follow-up and at relapse was analyzed for IGFBP-2. Control serum was from women undergoing pelvic or abdominal surgery for benign ovarian disease or nonovarian pathology. RESULTS: IGFBP-2 at diagnosis was significantly elevated (P < 0.0001) in women with ovarian cancer (887 +/- 62 ng/ml) compared with benign controls (337 +/- 25 ng/ml), and women undergoing nonovarian surgery (439 +/- 49 ng/ml) and correlated positively with tumor stage and cellular differentiation but not with CA125. Unexpectedly, IGFBP-2 levels increased additionally 1-week postoperatively in ovarian cancer patients (1581 +/- 90 ng/ml; P = 0.0027) as well as controls (977 +/- 95 ng/ml; P < 0.0001) and was higher in women who had suboptimal debulking compared with optimal debulking of their tumor. IGFBP-2 levels returned to normal in women without evidence of progressive disease, but remained significantly elevated in women who later relapsed. Patients with IGFBP-2 levels in the highest tertile at diagnosis had a significantly shorter progression-free interval and overall survival. CONCLUSION: In ovarian cancer IGFBP-2 is elevated at diagnosis, and corresponds to stage and histology with patients in the highest tertile of IGFBP-2 more likely to relapse and have a poorer outlook. Identification of these patients at diagnosis may allow more individualized, aggressive adjuvant treatment and follow-up, and IGFBP-2 may therefore be an important additional prognostic marker in this disease.     

Safety Behaviors of Abused Women After an Intervention During Pregnancy

Objective: To evaluate an intervention protocol, administered during pregnancy, for increasing safety-seeking behaviors of abused women.
Design: Prospective, ethnically stratified cohort analysis.
Setting: Public prenatal clinics.
Participants: Pregnant women reporting physical or sexual abuse in the year before or during the present pregnancy. One hundred thirty-two women met study criteria, received the intervention, and were followed for 1 year after the completion of the pregnancy.
Intervention: Three education, advocacy, and community referral sessions that included information on safety behaviors.
Main outcome Measure: Adoption of safety behaviors by abused women. Safety behaviors were measured before the intervention, twice during pregnancy, and at 2, 6, and 12 months after completion of the pregnancy.
Results: Repeated measures analysis of variance showed a significant increase in adoption of each safety behavior (p < .0001), with most behaviors showing a significant increase after the first intervention session.
Conclusions: Pregnant women who were abused and were offered an intervention protocol report a significant increase in safety behavior adoption during and after pregnancy. Abuse during pregnancy is common. Identification of abuse and immediate clinical intervention that includes information about safety behaviors can result in safety behavior adoption that may prevent future abuse and increase the safety and well-being of women and infants.