Fast and localized event-related optical signals (EROS) in the human occipital cortex: comparisons with the visual evoked potential and fMRI

Localized evoked activity of the human cortex produces fast changes in optical properties that can be detected noninvasively (event-related optical signal, or EROS). In the present study a fast EROS response (latency approximately 100 ms) elicited in the occipital cortex by visual stimuli showed spatial congruence with fMRI signals and temporal correspondence with VEPs, thus combining subcentimeter spatial localization with subsecond temporal resolution. fMRI signals were recorded from striate and extrastriate cortex. Both areas showed EROS peaks, but at different latencies after stimulation (100 and 200-300 ms, respectively). These results suggest that EROS manifests localized neuronal activity associated with information processing. The temporal resolution and spatial localization of this signal make it a promising tool for studying the time course of activity in localized brain areas and for bridging the gap between electrical and hemodynamic imaging methods.

Mismatch negativity during attend and ignore conditions in Alzheimer's disease

Mismatch negativities (MMNs) of the event-related potential to deviant tones and environmental sounds were recorded during active and ignore oddball sequences in young and elderly controls and patients with probable Alzheimer's disease (PAD). MMNs were smaller in the PAD waveforms compared to those of the controls, suggesting a degraded sensory memory trace in these subjects; however, under ignore conditions, environmental sounds elicited robust MMNs in the PAD group along with N2b and novelty P3 components in similar fashion to controls. As N2b and P3 are usually elicited by attended stimuli, these data suggest that in the PAD subjects, the highly deviant events involuntarily captured attention, perhaps reflecting the activation of an attentional switching mechanism. Because this passive switching is thought to reflect activation of a mechanism located in the frontal lobes, the data suggest that this putative frontal lobe mechanism is relatively intact in the early stages of the disease.

An in vitro method for detecting infectious Cryptosporidium oocysts with cell culture

Current assay methods to detect Cryptosporidium oocysts in water are generally not able to evaluate viability or infectivity. A method was developed for low-level detection of infective oocysts by using HCT-8 cells in culture as hosts to C. parvum reproductive stages. The infective foci were detected by labeling intracellular developmental stages of the parasite in an indirect-antibody assay with a primary antibody specific for reproductive stages and a secondary fluorescein isothiocyanate-conjugated antibody. The complete assay was named the focus detection method (FDM). The infectious foci (indicating that at least one of the four sporozoites released from a viable oocyst had infected a cell) were enumerated by epifluorescence microscopy and confirmed under Nomarski differential interference contrast microscopy. Time series experiments demonstrated that the autoreinfective life cycle in host HCT-8 cells began after 12 h of incubation. Through dilution studies, levels as low as one infectious oocyst were detected. The cell culture FDM compared well to other viability assays. Vital stains and excystation demonstrated that oocyst populations less than 1% viable (by vital dyes) and having a low sporozoite yield following excystation could not infect host cells. Until now, the water industry has relied on an oocyst detection method (under an information collection regulation) that is unable to determine viability. The quantifiable results of the cell culture method described demonstrate two important applications: (i) an infectivity assay that may be used in conjunction with current U.S. Environmental Protection Agency-mandated detection methodologies, and (ii) a method to evaluate oocyst infectivity in survival and disinfection studies.

Temporal segregation in coexisting spiny mice (genus Acomys): role of photoperiod and heterospecific odor

Daily rhythms of activity and body temperature were measured in golden spiny mice Acomys russatus, acclimated for 2 weeks, at least, to 2 different photoperiod regimes (16L:8D; 8L:16D) at a constant ambient temperature of 28 degrees C. For recording body temperature, VM-FM (Mini-Mitter Co. Inc., Sunriver, OR) transmitters were implanted. For activity measurements, an infrared sensor (Hengstar BL 68 907F, Japan, using a Lodestar PS-303 power supply, Taiwan) mounted on each cage. Both rhythms were also measured in the same individuals exposed to chemical signals released in the urine of A. cahirinus. The results of this study show that both rhythms of A. russatus correlate and respond to changes in photoperiod regimens, as well as to the chemical signals. However, the correlation changes under the 2 photoperiod regimens. Under LD acclimation, a decrease in the correlation is noted, as a response to the addition of chemical signals. Our results suggest that the different responses due to the different light regimens represent 2 seasons in nature, where presumably each season demands a different physiological response.

A developmental study of the effect of temporal order on the ERPs elicited by novel environmental sounds

Event-related brain potentials (ERPs) were recorded from 16 subjects in each of the following age groups, 5-7, 9-11, 14-16, and 20-28 years of age. Subjects performed a novelty oddball task, in which frequent, standard tones (80% probability) were intermixed with infrequent tones to which the subject responded (10%), along with 48 unique novel, environmental sounds (10%). Analyses focused on the effects of temporal order (either serial order within the block or block number) in interaction with age group on the ERPs to the novel sounds. The amplitude and scalp distribution of two ERP components were analyzed, the 'novelty P3,' assumed to reflect aspects of the orienting response, and the P32, a component that may be synonymous with the P3b. Evidence suggests that the frontal aspect of the scalp distribution of the novelty P3 depends upon the integrity of the prefrontal cortex. Temporal order produced systematic (primarily linear) reductions in novelty P3 amplitude that were greater at frontal than posterior electrode sites. The P3(2) did not show consistent effects of temporal order. Both of these phenomena were highly similar for all four age groups. It is concluded that the brain's response to novelty is similar across a wide age range, involving a neural circuit with both frontal and posterior elements.

Hernia repair in elderly patients

BACKGROUND

This study evaluates a 5-year experience of the management of the most frequent abdominal wall hernias in an elderly population.

METHODS

From April 1990 to December 1995, 231 inguinal, 12 femoral and seven umbilical hernias were repaired in 221 patients (mean age 74 (range 66-93) years). Concomitant diseases were present in 157 patients. A mesh repair was performed with 'tension-free' or 'plug' techniques in all but 23 inguinal and two femoral hernia repairs, in which the Bassini or Shouldice procedures were adopted. Ten emergency hernia repairs were performed for strangulation. A total of 232 operations, including four emergency hernia repairs, were carried out under local anaesthesia.

RESULTS

There was no perioperative mortality. Acute intestinal bleeding occurred 2 days after surgery in a patient with colonic diverticular disease. Urinary retention occurred once following emergency hernia repair under general anaesthesia and twice after elective hernia repair under local anaesthesia. Local complications included four scrotal haematomas (2 per cent), three wound infections (1 per cent) and one case of orchitis with atrophy after repair of a recurrent hernia. There was one recurrence after a Bassini repair and one after Shouldice inguinal herniorrhaphy. No recurrence was observed after mesh repair.

CONCLUSION

Local anaesthetic mesh hernia repair is safe and effective in elderly patients. Age should be no bar to elective hernia repair. This policy should avoid the complications of emergency operation.

Old/new differences in direct and indirect memory tests using pictures and words in within- and cross-form conditions: event-related potential and behavioral measures

Indirect measures of repetition priming are more sensitive to changes in surface features than are direct measures of memory. This dissociation may reflect differences in the extent to which the two tasks rely on form-specific processes, or on the activation of different memory systems. To assess this, subjects at study made semantic discriminations to a mixed list of pictures and words. At test, half the concepts were repeated in the surface form presented at study while half were repeated in the other surface form. Subjects in the indirect test continued making the same discrimination, whereas those in the direct test performed a yes/no recognition task. For both tasks, significant old/new within-form differences were found for event-related potential (ERP) and reaction time (RT) measures. Cross-form old/new differences were reliable only for the word-picture condition in the direct task and only for the ERP indices. These data suggest that both direct and indirect memory tasks are influenced by form-specific as well as form-non-specific processing, and that neither the transfer-appropriate processing nor memory systems approaches can completely account for this pattern of results.

Picture naming by young children: norms for name agreement, familiarity, and visual complexity

Researchers concerned with the development of cognitive functions are in need of standardized material that can be used with both adults and children. The present article provides normative measures for 400 line drawings viewed by 5- and 6-year-old children. The three variables obtained-name agreement, familiarity, and visual complexity-are important because of their potential effect on memory and other cognitive processes. The normative data collected in the present study indicate that young children are different from adults in both the name most frequently assigned and the number of alternative names provided. The alternative names given by the children are either coordinate names or names of objects that are visually similar to the pictured object. In addition, the failure (to name) rate is higher among young children compared to adults. Thus, we conclude that unequivocal interpretation of age-related differences in cognitive functions can be made only when age-appropriate pictorial stimuli are chosen.

Dissociations between memory for temporal order and recognition memory in aging

Young and old subjects participated in an experiment in which trials testing memory for temporal order (recency memory) and recognition memory were randomly intermixed with study trials in a continuous sequence. A dissociation was found between recency and recognition memory performance for pictorial stimuli. Relative to young adults, older adults performed at chance on recency memory trials whereas they were not impaired on recognition memory. Recency performance was correlated with measures derived from the Wisconsin Card Sorting test, whereas recognition performance was not. The results are discussed in terms of the role of the frontal lobes in temporal-order memory and of possible frontal lobe deterioration in normal aging.

Timing of surgery related to menstrual cycle and prognosis of premenopausal women with breast cancer

The influence of the timing of surgery in relation to the menstrual cycle on the survival of breast cancer patients has been both advocated and disputed. The records of 165 premenopausal M- breast cancer women consecutively operated from 1977 to 1991 were reviewed. All patients underwent modified radical mastectomies or quadrantectomies plus postoperative radiotherapy. Node-positive patients received adjuvant chemotherapy. Cox regression analysis was used to estimate the relative risk (RR) of death in three models including timing of surgery, age, histology, pT and pN. In each model, patients were divided into two groups according to the criteria proposed by Badwe, Hrushesky, and Senie. Multivariate analysis showed a significant association between pT and pN and survival, whereas no association with survival was observed for the timing of surgery according to either Badwe or Hrushesky or Senie (RR = 1.26, RR = 0.91 and RR = 0.88 respectively). Consensus on the menstrual phase related to the expected best prognosis is still required.

Effect of multiple presentations of words on event-related potential and reaction time repetition effects in Alzheimer's patients and young and older controls

The hallmark symptom in probable Alzheimer's disease (PAD) is dramatic difficulty in storing and/or retrieving new information on tests of explicit or direct memory. However, in many studies of implicit or indirect memory, these same patients show repetition-priming magnitudes (i.e., facilitation of performance on the basis of previous experience) similar to that of normal controls. Recent studies of repetition priming have shown that PAD subjects have an intact event-related potential (ERP) repetition effect, which is thought to index indirect memory functioning. The present study was designed to test the effect of multiple repetitions of verbal stimuli on the ERPs of PAD patients. ERPs were recorded from 8 subjects with PAD, 8 age-matched elderly and 16 young healthy controls. Subjects were asked to make speeded but accurate choice responses to infrequently occurring animal words and frequently occurring nonanimal words, some of which repeated across three blocks of trials. All groups of subjects produced ERP activity that was more positive to repeated (i.e., old) than to new items, with no additional enhancement elicited by the third presentation. ERP enhancement to repeated items was associated with reaction time facilitation, which also showed no additional facilitation to the third presentation. Moreover, the scalp distribution of the repetition effect was similar in the PAD and control groups, suggesting that it emanated from similar brain tissue in the three groups. These results indicate that ERP and reaction time repetition-priming effects are relatively intact in subjects who are aging normally and in those with a diagnosis of "mild" Alzheimer's disease.

[Lacking effect of timing of surgery in relation to the menstrual cycle on prognosis of breast cancer in premenopausal women]

The influence of timing of surgery in relation to menstrual period on survival of breast cancer patients has been both advanced advocated and disputed. A meta-analysis on published series showed a statistically significant overall odds reduction when surgery is performed in the luteal phase. The records of 165 premenopausal M- breast cancer women, not on hormonal therapies, consecutively operated on from 1977 to 1991 were reviewed. All patients underwent modified radical mastectomies or quadrantectomies plus operative radiotherapy, Node-positive patients received standard adjuvant chemotherapy. Cox regression analysis was used to estimate the relative risk (RR) of death in three models including timing of surgery, age, histology, pathological T and N. In each model, patients were divided into two groups according to the criteria proposed by Badwe, Hrushesky, and Senie. Multivariate analysis showed a significant association between pT and pN and survival, whereas no association with survival was observed for timing of surgery according to Badwe or Hrushesky or Senie criteria (RR = 1.26, RR = 0.91, and RR = 0.88 respectively). Up-to-date agreement on the menstrual phase and relative expected better prognosis is still lacking.

High-dose mitoxantrone with peripheral blood progenitor cell rescue: toxicity, pharmacokinetics and implications for dosage and schedule

The optimal use of mitoxantrone (NOV) in the high-dose range requires elucidation of its maximum tolerated dose with peripheral blood progenitor cell (PBPC) support and the time interval needed between drug administration and PBPC reinfusion in order to avoid graft toxicity. The aims of this study were: (1) to verify the feasibility and haematological toxicity of escalating NOV up to 90 mg m(-2) with PBPC support; and (2) to verify the safeness of a short (96 h) interval between NOV administration and PBPC reinfusion. Three cohorts of ten patients with breast cancer (BC) or non-Hodgkin's lymphoma (NHL) received escalating doses of NOV, 60, 75 and 90 mg m(-2) plus melphalan (L-PAM), 140-180 mg m(-2), with PBPC rescue 96 h after NOV. Haematological toxicity was evaluated daily (WHO criteria). NOV plasma pharmacokinetics was also evaluated, as well as NOV cytotoxicity against PBPCs. Haematological recovery was rapid and complete at each NOV dose level without statistically significant differences, and there were no major toxicities. NOV plasma concentrations at the time of PBPC reinfusion were below the toxicity threshold against haemopoietic progenitors. It is concluded that, when adequately supported with PBPCs, NOV can be escalated up to 90 mg m(-2) with acceptable haematological toxicity. PBPCs can be safely reinfused as early as 96 h after NOV administration.

An ERP developmental study of repetition priming by auditory novel stimuli

Event-related potentials were recorded from participants 5-7, 9-11, 14-16, and 22-28 years old during an auditory novelty oddball task. In this task, stimuli about which the participant is not instructed (i.e., novel or uncategorized) typically elicit a more frontally oriented P3 scalp topography (novelty P3). In contrast, stimuli to which the participant must respond (i.e., target or precategorized) elicit a P3 with a more posterior scalp topography. Repetition of identical novel stimuli led to a similar reduction in novelty P3 amplitude for all age groups. Moreover, with repetition the shift in scalp topography of the novelty P3 to a more parietally oriented distribution was similar in children and adults. A second component, the P3(2) (assumed to be an analog of the P3b), exhibited a repetition priming effect in both the adults and the youngest children. The fact that age-related differences induced by novel repetition were small and not systematic indicates that the processing of novel information is similar across a wide age range.

[Pregnancy after surgical therapy of obesity. Bibliographic review and our experience with biliopancreatic diversion]

BACKGROUND

An increasing number of women in childbearing age are submitted to surgical treatment of obesity; for this reason pregnancy represents a frequent event in operated patients.

METHODS

In this study pregnancy in patients with morbid obesity submitted to jejunoileal bypass (JIB) and gastric bypass (GB) are reviewed from the literature and the analysis of our experience with biliopancreatic diversion (BPD) is reported.

RESULTS

In 113 pregnancies after JIB reviewed from the literature, the results seem to be debated either about the course of pregnancy or about maternal and neonatal status. The data of literature concerning the pregnancies following GB are less debated but rather slight. One hundred and fifty-two pregnancies after BPD have a complete documentation concerning maternal conditions, modality of outcome and neonatal situation.

CONCLUSIONS

Pregnancy occurred in the obese women represents an increased maternal-fetal risk. The excess weight loss, the weight maintenance and the reduced weight changes during pregnancy are an advantage in the operate women who, in any case, need accurate controls of the nutritional status during the whole gestational period. Keeping these cautions pregnancy following surgical treatment of obesity represents an event not only possible but even with less problems than in pregnancy in obese women.

[Intrahepatic dilation of the bile ducts. Particularity of a clinical case]

We report the case of a 71 years old male patient with a "simple" form of Caroli's syndrome. The "simple" form is less common than the form associated with congenital hepatic fibrosis. In this case the intrahepatic bile duct dilatation was confined to the segments V and VI, and intrahepatic lithiasis and cholelithiasis were associated. Usually, Caroli's syndrome remains asymptomatic for the first 20 years of the patient's life, sometimes longer, and in few cases for the patient's whole life. "Simple" asymptomatic Caroli's syndrome is generally unrecognized and in our own case it was an intraoperative finding. Patient's age, the presence of a hepatitis C and the absence of malignant changes discouraged us from performing a right hepatectomy and then a Roux-en-Y intrahepatic bile duct jejunal anastomosis was done. One year after the operation the patient is leading a normal life, and he is symptom-free.

ERPs during study as a function of subsequent direct and indirect memory testing in young and old adults

Event-related potentials (ERPs) were recorded from young and older adults while words were studied during structural and semantic encoding tasks. Items were presented twice to assess repetition effects. Subsequent memory effects (i.e. Dm or difference in subsequent memory) associated with non-target study items were also evaluated. Memory for non-target study items was tested either indirectly (word stem completion) or directly (cued recall). There were small, but unreliable age differences (favoring the young) on both the indirect and direct tests. These small differences were consistent with previous results for stem completion performance, but were counter to expectation for the cued recall test, where young adults were expected to show clear superiority. We conclude, based on task considerations, that for cued recall, subjects may have adopted an 'implicit' retrieval strategy. Because older adults typically have little difficulty with implicit retrieval, they fared almost as well as the young on cued recall. Dm effects were reliable for the young only. As Dm is thought to reflect elaborative encoding processes, the larger Dm magnitudes in the young than the old suggest that the small, though unreliable, age-related performance differences that resulted may have been mediated by such elaborative processing on the part of the younger adults.

Improved oral delivery of desmopressin via a novel vehicle: mucoadhesive submicron emulsion

PURPOSE

Desmopressin acetate (DDAVP) is used parenterally and intranasally in the control of several diseases. Oral administration of DDAVP, while most desirable, is not practical presently due to low bioavailability. The objective of the present study was to explore the feasibility for employing oil-in-water MucoAdhesive SubMicron Emulsion (MA-SME), a novel mucoadhesive vehicle with polymer-coated droplets, for enhanced oral delivery of DDAVP.

METHODS

We used a modified pharmacopeal method, based on measurement of the antidiuretic activity, for the assessment of oral delivery of DDAVP in rats. DDAVP formulated in two MA-SME preparations, in non-mucoadhesive SME (plain-SME), in saline and in other control solutions was administered orally to rats via a stomach tube at a dose of 0.5 units/kg. At various times following DDAVP administration, water was given via a stomach tube. Excretion times for 30% and 60% of the total water load were measured.

RESULTS

Excretion times for DDAVP in MA-SME formulations were always longer (up to 2-fold) than those following DDAVP in saline. By contrast, excretion times for DDAVP in plain-SME and in non-SME Carbopol (a Mucoadhesive polymer) solution were virtually identical to those for DDAVP in saline.

CONCLUSIONS

Formulations of MA-SME were shown to generate substantial enhancement (up to 12-fold) of the rat oral bioavailability of DDAVP with regard to simple saline solution of the drug. From the results it is also evident that MA-SME, but not plain-SME or non-SME Carbopol solution, is responsible for the enhancement of oral delivery of DDAVP in rats.

Naming norms for brief environmental sounds: effects of age and dementia

Brief nontonal sounds are used in electrophysiology in the novelty oddball paradigm. These sounds vary in the brain activity they elicit and in the degree to which they can be identified, named, and remembered. Because ease of sound identification may influence sound processing, naming and conceptual norms were determined for 100 sounds for 77 young adults (Experiment 1). Naming ability decreases in normal and pathological aging. Therefore, norms were also derived for older adults (Experiment 2) and for probable Alzheimer's disease patients (Experiment 3). With respect to the young adults, perseverative naming behavior increased in these groups, and sound and picture naming performance were correlated. In Experiment 4, the sound-naming performance of children aged 5-6, 9-11, and 14-16 years was compared. Name and conceptual agreements improved with age, whereas perseverative behavior decreased. These normative data should be useful in guiding sound selection in future studies and help clarify the relationships between sound naming and other variables, including direct and indirect memory performance.

The air gun: toy or weapon?

Originally used in warfare, air guns are commonly used in target shooting, as toys, and as "beginner" guns for children. The projectile force of these weapons can rival that of many conventional handguns. Pneumatic weapons pose a serious threat to the pediatric population, and their potential for serious injury must be recognized.

Biliopancreatic diversion for obesity at eighteen years

BACKGROUND

Surgical attempts to treat obesity began because of the discouraging results of conservative medical treatment, which successfully achieved initial weight loss but failed to maintain it. Gastric restrictive procedures, currently the most popular surgical methods for obesity therapy, have proved to be effective in initiating weight loss, but some concerns regarding their long-term efficacy in weight maintenance have arisen.

METHODS

Of a total of 1968 obese patients who underwent biliopancreatic diversion since 1976, the last consecutive 1217 underwent the "ad hoc stomach" type of diversion with a 200 cm alimentary limb, a 50 cm common limb, and a gastric volume varying between 200 and 500 ml. Mean age was 37 years old (11 to 69 years), and mean excess weight was 117%. Maximum follow-up was 115 months with nearly 100% participation.

RESULTS

In the last half of the series, operative mortality was 0.4% with no general complications and with early surgical complications of wound dehiscence and infection (total, 1.2%) and late complications of incisional hernia (8.7%) and intestinal obstruction (1.2%). Mean percent loss initial excess weight (IEW) at 2, 4, 6, and 8 years was 78 +/- 16, 75 +/- 16, 78 +/- 18, and 77 +/- 16 in the patients with IEW up to 120% and 74 +/- 12, 73 +/- 13, 73 +/- 12, and 72 +/- 10 in those with IEW more than 120%. A group of 40 patients who underwent the original "half-half" biliopancreatic diversion maintained a mean 70% reduction of IEW during a 15-year follow-up period. Specific late complications included anemia (less than 5%), stomal ulcer (2.8%), protein malnutrition (7% with 1.7% requiring surgical revision by common limb elongation or by restoration). Clinical problems from bone demineralization were minimal in the short term and almost absent in the long term.

CONCLUSIONS

Biliopancreatic diversion is a very effective procedure but is potentially dangerous if used incorrectly.