[SRSF2 promotes glioblastoma cell proliferation by inducing alternative splicing of FSP1 and inhibiting ferroptosis]

Objective: To investigate the effect of serine/arginine-rich splicing factor 2 (SRSF2) on ferroptosis and its possible mechanism in glioblastoma cells. Methods: The online database of gene expression profiling interactive analysis 2 (GEPIA 2) and Chinese Glioma Genome Atlas were used to analyze the expression of SRSF2 in glioblastoma tissue and its association with patients prognosis. To validate the findings of the online databases, the pathological sections of glioblastoma and non-tumor brain tissues from Tianjin Medical University General Hospital, Tianjin, China were collected and analyzed by using immunohistochemistry. Silencing SRSF2 gene expression in glioblastoma cells by siRNA was analyzed with Western blot. The proliferation index was detected by using CCK8 assay. The rescued experiment was conducted by using expression plasmid of pcDNA3.1(+)-SRSF2. The activity of ferroptosis was assessed by using the levels of iron ions and malondialdehyde in glioblastoma cells and the changes in the ratio of glutathione to oxidized glutathione. The changes of gene expression and differential pre-mRNA alternative splicing (PMAS) induced by SRSF2 were monitored by using the third-generation sequencing technology analysis, namely Oxford nanopore technologies (ONT) sequencing analysis. Results: SRSF2 expression was higher in glioblastoma tissues than non-tumor brain tissues. Immunohistochemistry also showed a positive rate of 88.48%±4.60% in glioblastoma tissue which was much higher than the 9.97%±4.57% in non-tumor brain tissue. The expression of SRSF2 was inversely correlated with overall and disease-free disease survivals (P<0.01). The proliferation index of glioblastoma cells was significantly reduced by silencing with SRSF2 siRNA (P<0.01) and could be reversed with transfection of exogenous SRSF2. The levels of intracellulariron ions and malondialdehyde increased (P<0.05), but the glutathione/oxidized glutathione ratio and the expression of key proteins in the glutathione pathway remained unchanged (P>0.05). ONT sequencing results showed that silencing SRSF2 in glioblastoma cells could induce a significant alternative 3' splice site change on ferroptosis suppressor protein 1 (FSP1). Conclusion: SRSF2 inhibits the ferroptosis in glioblastoma cells and promotes their proliferation, which may be achieved by regulating FSP1 PMAS.

[Attention should be paid to the differentiationbetween benign paroxysmal positional vertigo and vestibular migraine]

As we know, benign paroxysmal positional vertigo is a peripheral vestibular disorder,while vestibular migraine is a central vestibular disease. Although they are two different independent diseases, patients often choose to consult otolaryngology and neurology. The clinical manifestations of some patients with these two diseases are similar and the diagnosis is easy to be confused, but the treatment methods are completely different, and incorrect treatment methods will inevitably affect the curative effect and prognosis. Vestibular migraine is characterized by a diversity of clinical manifestations and signs, and the migraine symptoms of some patients do not match with the vestibular symptoms. There are 30% of vestibular migraine patients who showed isolated paroxysmal vertigo/dizziness and nystagmus, which is easily confused with benign paroxysmal positional vertigo and needs to be identified. Under the framework of the international classification of vestibular diseases, according to the new guideline of nystagmus examination and classification issued by Barany Association and new diagnostic criteria of two diseases, differential diagnosisof benign paroxysmal positional vertigo from vestibular migrainecan make up for one-sided understanding caused by the specialization of disciplines, improve thediagnosis and treatment of vestibular diseases, and thus reduce the misdiagnosis and mistreatment.

[Etiological analysis on patients with vertigo or dizziness]

Objective: To explore the spectrum of causes for patients with vertigo or dizziness in the Department of Neurology, and provide a reference for diagnosis and treatment of patients with vertigo or dizziness. Methods: Clinical data of patients in the Department of Neurology, Baotou Central Hospital between January 2016 and September 2017 was retrospectively analyzed. The target group under study was diagnosed based on the uniform diagnostic criteria. Results: A total of 9 200 patients with a chief complaint of vertigo or dizziness were included. The ratio of male to female was 1∶1.8, with an age range of 19 to 85 years. The different etiology was as follows: benign paroxysmal positional vertigo (BPPV) (3 148 cases, 34.22%), persistent postural-perceptual dizziness (PPPD) (2 006 cases, 21.80%), vertigo caused by cerebrovascular diseases (1 463 cases, 15.90%), vestibular neuritis (741 cases, 8.05%), vestibular migraine (536 cases, 5.83%), vestibular paroxysmia (336 cases, 3.65%), Ménière disease (187 cases, 2.03%), drug-induced vertigo (96 cases, 1.04%), neurological degenerative diseases (74 cases, 0.80%), sudden sensorineural hearing loss (51 cases, 0.55%), multiple sclerosis and neuromyelitis optica (21 cases, 0.23%), other reasons (22 cases, 0.24%), unknown reasons (519 cases, 5.64%). Conclusions: Dizziness is resulted from various causes, and BPPV is the most common reason. Vertigo caused by cerebrovascular diseases appears to gradually increase along with age. PPPD is very common in clinical practice, so clinicians needs to be highly aware of BPPV and PPPD. Although those dizziness diseases have a low incidence, they should not be ignored. There are still certain proportion of vertigo patients whose diagnosis are undetermined.

Randomised clinical trial: faecal microbiota transplantation for recurrent Clostridum difficile infection - fresh, or frozen, or lyophilised microbiota from a small pool of healthy donors delivered by colonoscopy

BACKGROUND

Faecal microbiota transplantation (FMT) has become routine in managing recurrent C. difficile infection (CDI) refractory to antibiotics.

AIM

To compare clinical response and improvements in colonic microbiota diversity in subjects with recurrent CDI using different donor product.

METHODS

Seventy-two subjects with ≥3 bouts of CDI were randomised in a double-blind study to receive fresh, frozen or lyophilised FMT product via colonoscopy from 50 g of stool per treatment from eight healthy donors. Recipients provided stools pre- and 7, 14 and 30 days post-FMT for C. difficile toxin and, in a subset, microbiome composition by 16S rRNA gene profiling.

RESULTS

Overall resolution of CDI was 87% during 2 months of follow-up after FMT. Stool samples before FMT had significantly decreased bacterial diversity with a high proportion of Proteobacteria compared to donors. Cure rates were highest for the group receiving fresh product seen in 25/25 (100%), lowest for the lyophilised product 16/23 (78%; P = 0.022 vs. fresh and 0.255 vs. frozen) and intermediate for frozen product 20/24 (P = 0.233 vs. fresh). Microbial diversity was reconstituted by day 7 in the subjects receiving fresh or frozen product. Improvement in diversity was seen by day 7 in those randomised to lyophilised material with reconstitution by 30 days.

CONCLUSIONS

Comparative efficacy in faecal microbiota transplantation was observed in subjects receiving fresh or frozen faecal product from the same donors. The lyophilised product had a slightly lowered efficacy compared with fresh product, but it resembled other treatments in microbial restoration 1 month after faecal microbiota transplantation.

Etiology of travellers' diarrhea

Eleven published studies of the etiology of travellers' diarrhea (TD) were reviewed define the etiology of TD and to exam newly developed technology such as Real-Time multiplex polymerase chain reaction (PCR) to identify multiple pathogens in one assay to define the cause of TD. Using PCR methods bacterial pathogens were found in 72% of patients acquiring diarrhea in Latin America and in 80% in travellers with illness acquired in Southeast Asia). In these studies, enterotoxigenic Escherichia coli as the predominant pathogen (42% in Latin America and 28% in Southeast Asia). Ciprofloxacin-resistant Campylobacter was commonly associated with TD in Southeast Asia. Multiplex PCR has improved the detection of enteropathogens and allowed better assessment returning travellers hospitalized with TD and those with persistent diarrhea.

Measurement of Thermal Conductivity of Porcine Liver in the Temperature Range of Cryotherapy and Hyperthermia (250~315k) by A Thermal Sensor Made of A Micron-Scale Enameled Copper Wire

　　BACKGROUND: Cryotherapy and hyperthermia are effective treatments for several diseases, especially for liver cancers. Thermal conductivity is a significant thermal property for the prediction and guidance of surgical procedure. However, the thermal conductivities of organs and tissues, especially over the temperature range of both cryotherapy and hyperthermia are scarce.

OBJECTIVE

To provide comprehensive thermal conductivity of liver for both cryotherapy and hyperthermia.

MATERIALS AND METHODS

A hot probe made of stain steel needle and micron-sized copper wire is used for measurement. To verify data processing, both the least square method and the Monte Carlo inversion method are used to determine the hot probe constants, respectively, with reference materials of water and 29.9 % Ca₂Cl aqueous solution. Then the thermal conductivities of Hanks solution and pork liver bathed in Hanks solution are measured.

RESULTS

The effective length for two methods is nearly the same, but the heat capacity of probe calibrated by the Monte Carlo inversion is temperature dependent. Fairly comprehensive thermal conductivity of porcine liver measured with these two methods in the target temperature range is verified to be similar.

CONCLUSION

We provide an integrated thermal conductivity of liver for cryotherapy and hyperthermia in two methods, and make more accurate predictions possible for surgery. The least square method and the Monte Carlo inversion method have their advantages and disadvantages. The least square method is available for measurement of liquids that not prone to convection or solids in a wide temperature range, while the Monte Carlo inversion method is available for accurate and rapid measurement.

DETERMINATION OF CONVECTIVE HEAT TRANSFER COEFFICIENT AT THE OUTER SURFACE OF A CRYOVIAL BEING PLUNGED INTO LIQUID NITROGEN

BACKGROUND

Cell survival upon cryopreservation is affected by the cooling rate. However, it is difficult to model the heat transfer process or to predict the cooling curve of a cryoprotective agent (CPA) solution due to the uncertainty of its convective heat transfer coefficient (h).

OBJECTIVE

To measure the h and to better understand the heat transfer process of cryovials filled with CPA solution being plunged in liquid nitrogen.

MATERIALS AND METHODS

The temperatures at three locations of the CPA solution in a cryovial were measured. Different h values were selected after the cooling process was modeled as natural convection heat transfer, the film boiling and the nucleate boiling, respectively. And the temperatures of the selected points are simulated based on the selected h values. h was determined when the simulated temperature best fitted the experimental temperature.

RESULTS

When the experimental results were best fitted, according to natural convection heat transfer model, h(1) = 120 W/(m(2)·K) while due to film boiling and nucleate boiling regimes h(f) = 5 W/(m(2)·K) followed by h(n) = 245 W/(m(2)·K). These values were verified by the differential cooling rates at the three locations of a cryovial.

CONCLUSION

The heat transfer process during cooling in liquid nitrogen is better modeled as film boiling followed by nucleate boiling.

Regulating the hydrothermal synthesis of ZnO nanorods to optimize the performance of spirally hierarchical structure-based glucose sensors

Synthesizing parameters of ZnO nanorods significantly affect the surface morphologies and further the performance of spirally hierarchical structure-based glucose sensors.

Clostridium difficile infection in hospitalized cancer patients in Beijing, China is facilitated by receipt of cancer chemotherapy

The purpose of this study was to determine the presence of Clostridium difficile infection (CDI) and risk factors for infection in hospitalized patients with diarrhea in a cancer hospital in Beijing, China. A total of 277 patients with hospital-associated diarrhea (HAD) were studied of which 41 (15%) were positive for fecal C. difficile toxin A/B. For each CDI case identified, a control with HAD but negative C. difficile specimen was enrolled to look for CDI risk factors. Receipt of cancer chemotherapy occurred in 20 (49%) patients with CDI and 9 (22.0%) patients with non-CDI HAD (OR3.39, 95%CI 1.78-10.05). Median length of chemotherapy before HAD developed was 39 days for those with CDI and 22 days for patients with CDI-negative HAD (P = 0.0391). The study found that CDI is commonly seen in cancer patients in China with increasing risk for patients who receive chemotherapy.

A clinical risk index for Clostridium difficile infection in hospitalised patients receiving broad-spectrum antibiotics

Identification of a population at high risk for Clostridium difficile infection (CDI) would enable CDI prevention strategies to be designed. The purpose of this study was to create a clinical risk index that would predict those at risk for CDI. A CDI risk index was therefore developed, based on a cohort of hospital patients given broad-spectrum antibiotics, and divided into a development and validation cohort. Logistic regression equations helped identify significant predictors of CDI. A scoring algorithm for CDI risk was created using identified risk factors and collapsed to create four categories of CDI risk. The area under the receiver operating characteristic (aROC) curve was used to measure goodness-of-fit. Among 54 226 patients, 392 tested positive for C. difficile. Age 50-80 years [odds ratio (OR: 0.5; P<0.0116)], age >80 years (OR: 2.5; P<0.0001), haemodialysis (OR: 1.5; P=0.0227), non-surgical admission (OR: 2.2; P<0.0001) and increasing length of stay in the intensive care unit (OR: 2.1; P<0.0001) were significantly associated with CDI. A simple risk index using presence of significant variables was significantly associated with increasing risk for CDI in both development (OR: 3.57; P<0.001; aROC: 0.733) and validation (OR: 3.31; P<0.001; aROC: 0.712) cohorts. An OR-derived risk index did not perform as well as the simple risk index. This easily implemented risk index should allow stratification of patients into risk group categories for development of CDI and help fashion preventive strategies.

Rifaximin: in vitro and in vivo antibacterial activity--a review

In vitro inhibitory activity of rifaximin is directed against Gram-positive and Gram-negative, aerobic and anaerobic bacteria. It is effective in the treatment of gastrointestinal infections when given orally because of the high concentration of the drug remaining in the gut lumen. Laboratory investigations have been carried out to assess the in vitro activity of rifaximin on different bacterial strains isolated from both human and domestic animals. The objective of this project is to review the in vitro and in vivo activity of rifaximin against bacterial infection with Gram-negative rods, Gram-positive rods and Gram-positive cocci and their resistance to rifaximin. The available data suggest that rifaximin is active in vitro and in vivo in the treatment of bacterial infection of adults and children.

One-third of term babies after perinatal hypoxia-ischaemia have transient hearing impairment: dynamic change in hearing threshold during the neonatal period

AIM

To examine the process of change in hearing threshold during the neonatal period after perinatal hypoxia-ischaemia.

METHODS

The threshold of brainstem auditory evoked responses (BAER) was measured serially during the first month after birth in 92 term babies who suffered hypoxia-ischaemia.

RESULTS

The mean BAER threshold in these babies was significantly increased on day 1 (ANOVA p < 0.001). The elevated threshold decreased progressively on days 3 and 5, but was still significantly higher than that in normal controls (p < 0.01). The elevation continuously decreased more slowly on days 10 and 15, and to a near normal level on day 30. Threshold elevation was seen in 31.7% of the babies on day 1, and 34.5% during the first three days. The rate of elevation decreased progressively thereafter. On day 30, 10.6% of the subjects still had increased thresholds. Moderate to severe elevation occurred mainly during the first week and severe elevation occurred predominately on day 1. Threshold elevation starting after days 3-5 is likely to be due to middle-ear disorders. As a whole, during the first month, 44.6% (41/92) of the babies studied had threshold elevation. BAER threshold was correlated weakly with the stage of hypoxic-ischaemic encephalopathy on days 1 and 3. The threshold was significantly higher in babies with severe encephalopathy than in those with mild or moderate encephalopathy during the first 3 d of life.

CONCLUSION

Hearing threshold is elevated in about one-third of term babies after hypoxia-ischaemia. The elevated threshold decreases progressively after birth, and returns to normal by one month in most babies. The threshold correlates weakly with the severity of encephalopathy.

Brainstem auditory-evoked responses to different rates of clicks in small-for-gestational age preterm infants at term

AIM

To clarify further the influence of intrauterine growth retardation (IUGR) on early neural development.

METHODS

In 30 small-for-gestational age (SGA) preterm infants at term, brainstem auditory-evoked responses (BAERs) were recorded with clicks of different repetition rates. All infants had a birthweight < 3rd centile, without any other major perinatal complications.

RESULTS

Compared with the BAER in 36 appropriate-for-gestational age (AGA) term infants, the preterm SGA infants did not show any abnormalities at 21 s(-1) clicks, except for a slight increase in wave III amplitude. At 51 s(-1) clicks, there was an increase in III-V/I-III interval ratio (ANOVA p < 0.05). At 91 s(-1), the I-III interval shortened, whereas the III-V interval and III-V/I-III interval ratio increased (all p < 0.05). Wave V amplitude tended to increase slightly at all repetition rates of clicks used, although this increase did not reach statistical significance. The III-V interval and III-V/I-III interval ratio in the preterm SGA infants at different click rates correlated inversely with occipitofrontal head circumference at the time of testing, i.e. the smaller the head the longer the III-V interval (all p < 0.01). Wave III amplitude at 21 s(-1) also correlated inversely with head circumference (p < 0.01), suggesting that the slight increase in this amplitude in the preterm SGA infants is related to their relatively small head size.

CONCLUSION

There were no major abnormalities in the BAER up to 91 s(-1) clicks at term in preterm SGA infants. The slight increase in III-V interval at high-rate stimulation suggests a subtle degree of central neural dysfunction, which is associated with small head size following IUGR.

Emergence of trimethoprim-resistant Escherichia coli in healthy persons in the absence of prophylactic or therapeutic antibiotics during travel to Guadalajara, Mexico

Thirty-nine healthy US students without diarrheal disease and who had not received prophylactic or therapeutic antibiotics were monitored for emergence of trimethoprim-resistant gram-negative fecal flora for a 3-week period after arrival in Guadalajara, Mexico. During this time period, most students showed no change in total fecal gram-negative bacteria (p > 0.05) but showed an increasing level of trimethoprim (TMP) resistance (p < 0.01) among fecal coliforms. Escherichia coli was the TMP-resistant organism isolated in 18 of 39 (46%) healthy students. These 18 TMP-resistant E. coli were also resistant to ampicillin (44%), azithromycin (11%), chloramphenicol (39%), ciprofloxacin (11%), doxycycline (89%), erythromycin (100%), furazolidone (72%), levofloxacin (17%), trimethoprim-sulfamethoxazole (89%) and trovafloxacin (17%). In the absence of prophylactic and therapeutic antibiotics, increased acquisition of TMP-resistant gram-negative fecal flora in this developing country is probably due to poor sanitary conditions and the recurrent and heavy exposure to antimicrobial-resistant indigenous flora as a result of contaminated food and drink.

Rifaximin versus ciprofloxacin for the treatment of traveler's diarrhea: a randomized, double-blind clinical trial

Rifaximin is a poorly absorbed rifamycin derivative under investigation for treatment of infectious diarrhea. Adult students from the United States in Mexico and international tourists in Jamaica were randomized to receive either rifaximin (400 mg twice per day) or ciprofloxacin (500 mg twice per day) for 3 days, following a double-blinded model, from June 1997 to September 1998. A total of 187 subjects with diarrhea were studied. Time from initiation of therapy to passage of last unformed stool was comparable for those receiving rifaximin or ciprofloxacin (median, 25.7 hours versus 25.0 hours, respectively). There was no significant difference in the proportion of subjects in the 2 groups with respect to clinical improvement during the first 24 hours (P=.199), failure to respond to treatment (P=.411), or microbiological cure (P=.222). The incidence of adverse events was low and similar in each group. Rifaximin is a safe and effective alternative to ciprofloxacin in the treatment of traveler's diarrhea.

Comparison of brainstem auditory evoked responses recorded at different presentation rates of clicks in term neonates after asphyxia

This study examined whether high presentation rates of clicks while recording brainstem auditory evoked responses (BAER) can improve the detection of central auditory impairment in asphyxiated neonates using the BAER. The BAER was analysed at different presentation rates of clicks within the first week after birth in 38 term neonates who suffered perinatal asphyxia. At the routinely used 21 s(-1) clicks all BAER wave latencies increased significantly (ANOVA, p < 0.05-0.01). After excluding five neonates who had a significantly elevated BAER threshold, only wave V latency increased slightly (p < 0.05). The interpeak intervals of I-V and III-V also increased slightly (both p < 0.05). Similar results were found at 51 s(-1) clicks. As the clicks were increased to 91 s(-1), the III-V interval increased more significantly (p < 0.01) and the III-V/I-III interval ratio also increased significantly (p < 0.01). In particular, wave V amplitude reduced more significantly than that in normal term controls (p < 0.01). Compared with values in the controls, wave V amplitude reduced by 4.5%, 12.2% and 24.7% at 21, 51 and 91 s(-1) clicks, respectively.

CONCLUSION

Although a moderate increase in the rate (e.g. 51 s(-1)) while recording the BAER did not improve the detection of hypoxic-ischaemic auditory impairment, a significant increase (e.g. 91 s(-1)) did, which mainly indicates an abnormal reduction in wave V amplitude.

Hearing impairment in preterm very low birthweight babies detected at term by brainstem auditory evoked responses

Seventy preterm babies who were born with a birthweight <1500 g were studied with brainstem auditory evoked responses (BAER) at 37-42 wk of postconceptional age. The data were compared with those of normal term neonates to determine the prevalence of hearing impairment in preterm very low birthweight (VLBW) babies when they reached term. The BAER was recorded with click stimuli at 21 s(-1). Wave I and V latencies increased significantly (ANOVA p < 0.01 and 0.001). I-V and III-V intervals also increased significantly (p < 0.05 and 0.001). Wave V amplitude and V/I amplitude ratio did not differ significantly from those in the normal term controls. Ten of the 70 VLBW babies had a significant elevation in BAER threshold (>30 dB normal hearing level). Eleven had an increase in I-V interval (>2.5 SD above the mean in the normal controls) and one had a decrease in V/I amplitude ratio (<0.45). These results suggest that 14% (10/70) of the VLBW babies had a peripheral hearing impairment and 17% (12/70) a central impairment. Three babies had both an increase in I-V interval and an elevation in BAER threshold, suggesting that 4% (3/70) had both peripheral and central impairments. Thus, the total prevalence of hearing impairment was 27% (19/70).

CONCLUSION

About one in four preterm VLBW babies has peripheral and/or central hearing impairment at term. VLBW and its associated unfavourable perinatal factors predispose the babies to hearing impairment.

EnteroaggregativeEscherichia colias a Major Etiologic Agent in Traveler's Diarrhea in 3 Regions of the World

Enteroaggregative Escherichia coli (EAEC) has been reported to cause traveler's diarrhea and persistent diarrhea in children in developing countries and in immunocompromised patients. To clarify the prevalence of EAEC in traveler's diarrhea, we studied 636 US, Canadian, or European travelers with diarrhea: 218 in Guadalajara, Mexico (June--August 1997 and 1998), 125 in Ocho Rios, Jamaica (September 1997--May 1998), and 293 in Goa, India (January 1997--April 1997 and October 1997--February 1998). Stool samples were tested for conventional enteropathogens. EAEC strains were identified by use of the HEp-2 assay. EAEC was isolated in 26% of cases of traveler's diarrhea (ranging from 19% in Goa to 33% in Guadalajara) and was second only to enterotoxigenic E. coli as the most common enteropathogen in all areas. Identification of EAEC reduced the number of cases for which the pathogen was unknown from 327 (51%) to 237 (37%) and explained 28% of cases with unknown etiology. EAEC was a major cause of traveler's diarrhea in 3 geographically distinct study areas.

In vitro antimicrobial susceptibility testing of bacterial enteropathogens causing traveler's diarrhea in four geographic regions

The emergence of resistant enteropathogens has been reported worldwide. Few data are available on the contemporary in vitro activities of commonly used antimicrobial agents against enteropathogens causing traveler's diarrhea (TD). The susceptibility patterns of antimicrobial agents currently available or under evaluation against pathogens causing TD in four different areas of the world were evaluated. Pathogens were identified in stool samples from U.S., Canadian, or European adults (18 years of age or older) with TD during 1997, visiting India, Mexico, Jamaica, or Kenya. MICs of 11different antimicrobials were determined against 284 bacterial enteropathogens by the agar dilution method. Ciprofloxacin, levofloxacin, ceftriaxone, and azithromycin were highly active in vitro against the enteropathogens, while traditional antimicrobials such as ampicillin, trimethoprim, and trimethoprim/sulfamethoxazole showed high levels and high frequencies of resistance. Rifaximin, a promising and poorly absorbable drug, had an MIC at which 90% of the strains tested were inhibited of 32 microg/ml, 250 times lower than the concentration of this drug in the stools. Amdinocillin, nalidixic acid, and doxycycline showed moderate activity. Fluoroquinolones are still the drugs of choice for TD in most regions of the world, although our study has a limitation due to the lack of Escherichia coli samples from Kenya and possible bias in selection of the patients for evaluation. Azithromycin and rifaximin should be considered as promising new agents. The widespread in vitro resistance of the traditional antimicrobial agents reported since the 1980s and the new finding of resistance to fluoroquinolones in Southeast Asia are the main reasons for monitoring carefully the antimicrobial susceptibility patterns worldwide and for developing and evaluating new antimicrobial agents for the treatment of TD.

Low-income minority women at risk for cervical cancer: a process to improve adherence to follow-up recommendations

OBJECTIVE

The Houston Department of Health and Human Services (HDHHS) has a centralized process for notifying and setting up follow-up appointments for women with abnormal Pap smears who are clients of HDHHS health centers. Faculty and a student from the University of Texas School of Public Health and HDHHS personnel jointly conducted a study to evaluate the process and performance of the system.

METHODS

The study examined two subpopulations: women with atypical squamous cells of undetermined significance or low-grade squamous intraepithelial lesions (ASCUS/LGSIL) and women with high-grade squamous intraepithelial lesions or atypical glandular cells of undetermined significance (HGSIL/AGCUS). A retrospective study was conducted of data on women attending eight HDHHS clinics during the period from February 1996 through August 2000. Records of 1,216 women referred for evaluation of abnormal Pap smears were reviewed. Process effectiveness was measured by the number of successful contacts made and the number of appointments set up. Performance was measured by compliance with referral appointments. Predictors included race/ethnicity, age, co-existence of a sexually transmitted disease, number of prior referrals, type of patient visit, and health center attended.

RESULTS

HDHHS staff successfully notified 95.6% of women with ASCUS/LGSIL and 97.9% of women with HGSIL/AGCUS. Using performance criteria as outcome measures, high-risk women requiring targeted interventions were identified. Overall, 84.2% of women scheduled appointments. Among those with ASCUS/LGSIL, women identified as African American were 53% less likely to accept an appointment and 45% less likely to show up for the appointment than those identified as Hispanic or "other." Age and type of patient visit appeared to be significantly associated with patient compliance behavior.

CONCLUSION

The study describes the effectiveness of a centralized patient follow-up process for women at risk for cervical cancer.

Maximum length sequence brainstem auditory evoked responses in term neonates who have perinatal hypoxia-ischemia

Maximum length sequence brainstem auditory evoked response (BAER) was studied within the first week after birth in 28 term neonates who had perinatal hypoxia-ischemia, or asphyxia. In the BAER recorded using conventional averaging techniques (click rate 21/s), the only abnormality was a slight increase in III-V interval, in addition to an increase in wave latencies when including those who had an elevated threshold (t test, all p<0.05). In the maximum length sequence BAER, however, both the III-V and I-V intervals in the asphyxiated infants were significantly increased at all the 91/s, 227/s, 455/s, and particularly 910/s click rates (p<0.05-0.001). The I-III interval was also increased significantly at 455/s and 910/s click rates (both p< 0.05). Wave V amplitude was significantly reduced at all the click rates used (ANOVA, p<0.05-0.001), particularly at 910/s, which sometimes was the only abnormality indicative of brain damage. Both the amplitude ratios V/I and V/III were significantly decreased at 455/s and 910/s click rates (p<0.01 or 0.001). A general trend was that BAER abnormalities after hypoxia-ischemia became more prominent as click rate was increased. Significant abnormalities occurred mainly at very high click rates (455/s and 910/s), which can be achieved using the maximum length sequence technique but not by using conventional averaging techniques. Thus, this technique, which can be used at the cribside, appears to be a better method for the early detection of brain damage after hypoxia-ischemia than using conventional averaging techniques, enhancing the diagnostic value of the BAER.

In vitro activity and fecal concentration of rifaximin after oral administration

Rifaximin showed moderately high MICs (the MIC at which 90% of the isolates tested were inhibited = 50 microg/ml) for 145 bacterial enteropathogens from patients with traveler's diarrhea acquired in Mexico during the summers of 1997 and 1998. Rifaximin concentrations in stool the day after oral administration (800 mg daily for 3 days) were high (average, 7,961 microg/g), proving the value of the drug.

Markers of enteric inflammation in enteroaggregative Escherichia coli diarrhea in travelers

As part of a traveler's diarrhea study carried out in Guadalajara, Mexico, and Goa, India, we conducted a case control study to evaluate fecal markers of enteric inflammation in three groups. Forty-five cases of enteroaggregative Escherichia coli (EAEC) diarrhea were compared to 56 controls with enterotoxigenic E. coli (ETEC) diarrhea, and 126 controls with diarrhea without identifiable pathogens. For EAEC cases we found fecal leukocytes, occult blood, and lactoferrin in 13 (28.9%), 14 (31.1%), and 27 (60.0%) patients, respectively; for ETEC controls they were 15 (26.8%), 16 (28.6%), and 15 (26.8%) respectively; and for patients without identifiable pathogens 19 (15.1%), 34 (27.0%) and 27 (21.4%) were seen for the presence of a positive fecal lactoferrin test in EAEC cases was statistically significant compared to both control groups. The study provides evidence that EAEC infection is associated with an intestinal inflammatory response.

Intestinal secretory immunoglobulin A response to enteroaggregative Escherichia coli in travelers with diarrhea

We examined stool samples from travelers for secretory immunoglobulin A (sIgA) to enteroaggregative Escherichia coli (EAEC) during episodes of acute diarrhea. Ten paired samples from 10 patients with diarrhea caused by EAEC were examined for the presence of specific sIgA by dot blot and Western blot immunoassays. Five samples were positive by dot blotting, and two samples were positive by Western blotting.

Characterization of enterotoxigenic Escherichia coli strains in patients with travelers' diarrhea acquired in Guadalajara, Mexico, 1992-1997

The relationship between enterotoxigenic Escherichia coli (ETEC) and travelers' diarrhea was examined in a high-risk area in 1992-1997. Toxin patterns, colonization-factor antigens (CFAs), and in vitro antimicrobial susceptibility were determined. In total, 928 US students with diarrhea acquired in Guadalajara, Mexico, were screened for enteric pathogens. Diagnosis of ETEC infection was done with oligonucleotide probes. ETEC was isolated in 19.9% of the travelers with diarrhea. CFAs were identified in 51% of the ETEC strains. The highest CFA frequency was observed among heat-stable isolates. Ampicillin, furazolidone, and sulfisoxazole resistance of ETEC increased during the study period. ETEC isolation rates and CFA patterns varied little during the 6 years of the study, which has implications for immunoprophylactic strategies. The finding that differences in the results of ribotyping and plasmid analysis change over time suggests that multiple strains of ETEC were responsible for the illness in the region studied.

Etiology of travelers' diarrhea on a Caribbean island

BACKGROUND

Between December 6, 1994 and March 10, 1996, a study of the etiology of diarrhea was carried out among 332 travelers to five all-inclusive hotels in Negril, Jamaica.

METHODS

Stool specimens were collected and sent to Montego Bay for laboratory analysis. Escherichia coli strains isolated at the Jamaican laboratory were sent to Houston for toxin testing.

RESULTS

A recognized enteropathogen was found in 118 of the 332 (35.5%) cases. Enterotoxigenic E. coli (ETEC) were the most commonly identified pathogen (87/332; 26.2%) followed by Salmonella (4.2%) and Shigella (4.2%). Clustering of etiologically defined cases was studied at each hotel. A cluster was defined as 2 or more cases with the same pathogen identified in the same hotel within 7 days. In the 3 hotels with the highest number of cases of diarrhea, enteropathogens were part of a cluster in 65 of 99 cases (65.7%) of diarrhea of which an etiologic agent was identified. In the other 2 hotels, only 4 of 20 cases (20%) occurred in clusters.

CONCLUSIONS

A total of 25 clusters of travelers' diarrhea cases was detected at the five hotels during the study period. Seventeen of 25 (68%) ETEC isolations occurred as part of a clustering of diarrhea cases. The largest outbreak of pathogen-identified diarrhea consisted of 7 cases of ETEC producing both heat-stable and heat-labile enterotoxins. In the Jamaican hotels with all inclusive meal packages most diarrhea cases occurred as small clusters, presumably as the result of foodborne outbreaks.

5-Lipoxygenase-derived oxylipins from the red alga Rhodymenia pertusa

The lipid extract of the temperate red alga Rhodymenia pertusa has yielded four eicosanoid metabolites, three of which are new natural products. Using principally NMR and MS techniques, their structures were deduced as 5R,6S-dihydroxy-7(E),9(E),11(Z),14(Z)-eicosatetraenoic acid (5R,6S-diHETE), 5R*,6S*-dihydroxy-7(E),9(E),11(Z),14(Z),17(Z)-eicosapentaenoic acid (5R*,6S*-diHEPE), 5-hydroxy-6(E),8(Z),11(Z),14(Z)-eicosatetraenoic acid (5-HETE), 5-hydroxy-6(E),8(Z),11(Z),14(Z),17(Z)-eicosapentaenoic acid (5-HEPE). The co-occurrence of these metabolites strongly suggests that R. pertusa contains a unique 5R-lipoxygenase system acting on both arachidonic and eicosapentaenoic acids.

Improved detection of enterotoxigenic Escherichia coli among patients with travelers' diarrhea, by use of the polymerase chain reaction technique

This study sought to determine whether a specific polymerase chain reaction (PCR) for enterotoxigenic Escherichia coli (ETEC) toxins after chaotropic extraction of DNA from stool would increase the detection of ETEC over that of conventional oligonucleotide probe hybridization of 5 E. coli colonies per stool sample (a standard method). By DNA hybridization, 29 (21%) of 140 patients were positive for ETEC, and 59 (42%) of 140 were positive for ETEC when PCR was used. Sensitivity of the PCR assay was confirmed through spiked stool experiments to be approximately 100-1000 ETEC colonies per sample. Specificity of the assay was determined by showing an absence of ETEC by the PCR technique in a subgroup of 48 subjects and by confirming the presence of ETEC DNA of positive samples by dot blot procedure. PCR technique detected significantly more ETEC infections in these subjects than did the hybridization method (P<.0001).

Conductive hearing loss produces a reversible binaural hearing impairment

Conductive hearing loss, produced by otitis media with effusion, is widespread in young children. However, little is known about its short- or long-term effects on hearing or the brain. To study the consequences of a conductive loss for the perception and processing of sounds, we plugged the left ear canal of ferrets for 7-15 months during either infancy or adulthood. Before or during plugging, the ferrets were trained to perform a binaural task requiring the detection of a 500 Hz tone, positioned 90 degrees to the right, that was masked by two sources of broad-band noise. In one condition ("control"), both noise sources were 90 degrees right and, in the second condition ("bilateral"), one noise source was moved to 90 degrees left. Normal ferrets showed binaural unmasking: tone detection thresholds were lower (mean 10.1 dB) for the bilateral condition than for the control condition. Both groups of ear-plugged ferrets had reduced unmasking; the mean residual unmasking was 2.3 dB for the infant and 0.7 dB for the adult ear-plugged animals. After unplugging, unmasking increased in both groups (infant, 7.1 dB; adult, 6.9 dB) but not to normal levels. Repeated testing during the 22 months after unplugging revealed a gradual return to normal levels of unmasking. These results show that a unilateral conductive hearing loss, in either infancy or adulthood, impairs binaural hearing both during and after the hearing loss. They show scant evidence for adaptation to the plug and demonstrate a recovery from the impairment that occurs over a period of several months after restoration of normal peripheral function.

Brainstem auditory evoked response recorded using maximum length sequences in term neonates

Brainstem auditory evoked response (BAER) was studied in term neonates using maximum length sequences (MLS), which allows presentation of acoustic stimuli at much higher rate than possible with conventional averaging technique. The response waveforms, especially for waves III and V, were well defined at the click rates of 91-455/s. Wave latencies and interpeak intervals at various click rates were all significantly longer and wave V amplitude was smaller in the neonates than in the adults. As click rate was increased, wave latencies increased and amplitudes progressively reduced. The slopes of wave latency-rate functions were progressively steeper for the later waves. The slopes of both III-V and I-V interval-rate functions were significantly steeper in the neonates than in the adults, indicating greater rate-dependent changes in the central components of the neonatal MLS BAER. These rate-dependent changes in the neonatal MLS BAER are generally similar to those in neonatal conventional BAER, although there are some differences. The results indicate that the neonatal brainstem can process rapid acoustic stimulation up to 455/s, although this ability remains immature.

Enteroaggregative Escherichia coli as a cause of traveler's diarrhea: clinical response to ciprofloxacin

The purpose of this study was to determine the role of enteroaggregative Escherichia coli (EAEC) in the development of traveler's diarrhea and the clinical response of patients with EAEC diarrhea following treatment with ciprofloxacin. Sixty-four travelers with diarrhea and no other recognized enteropathogen were enrolled in treatment studies in Jamaica and Mexico from July 1997 to July 1998. EAEC was isolated from 29 travelers (45.3%). There was a significant reduction in the duration of posttreatment diarrhea in the 16 patients treated with ciprofloxacin, as compared with that in the 13 patients who received placebo (mean of 35.3 versus 55.5 hours; P = .049). There was a nonsignificant reduction in the mean number of unformed stools passed during the 72 hours after enrollment in the ciprofloxacin-treated group (5.6), as compared with that in the placebo group (7.5) (P = .128). This study provides additional evidence that EAEC should be considered as a cause of antibiotic-responsive traveler's diarrhea.

Lobophorins A and B, new antiinflammatory macrolides produced by a tropical marine bacterium

Two new antiinflammatory macrolides, lobophorins A and B (1 and 2), have been isolated from fermentation broths of a marine bacterium isolated from the surface the Caribbean brown alga Lobophora variegata (Dictyotales). The new compounds, distantly related to antibiotics of the kijanimicin class, are potent inhibitors of topical PMA-induced edema in the mouse ear assay when administered either topically or IP.

Outcome of brain stem auditory electrophysiology in children who survive purulent meningitis

Brain stem auditory electrophysiology was assessed in children long after purulent meningitis by examining the central components of brain stem auditory evoked response (BAER) at different presentation rates of clicks. Children with peripheral hearing loss were excluded from this study to avoid any possible influence of the loss on the measurements of BAER central components. Of the 70 children who had recovered from meningitis 2 to 8 years earlier, 9 (12.9%) showed abnormalities in BAER central components--mainly a slight reduction of wave V amplitude, at the click presentation rate of 10/s. Of the remaining 61 children who did not show any obvious abnormalities in the BAER at 10/s, an abnormally prolonged I-V interval and a reduced amplitude of wave V were seen in 5 children (8.2%) at the click rate of 90/s. The total BAER abnormality rate was therefore 20.0% (14/70 cases). The results suggest that most children who survive purulent meningitis have a favorable outcome for the brain stem auditory pathway, with about 1 in 5 having mild dysfunction or a suboptimal outcome in the pathway.

Etiology of outpatient pediatric nondysenteric diarrhea: a multicenter study in the United States

BACKGROUND

Few data have been published recently on the etiology of outpatient pediatric diarrhea in the US.

METHODS

We determined the etiology of acute, nondysenteric diarrhea among 147 children between 2 and 11 years old presenting to 9 outpatient clinics in various regions of the US between August, 1991, and August, 1993. Enteropathogens were sought by conventional laboratory methods. The various diarrheagenic Escherichia coli were sought.

RESULTS

A recognized etiologic agent was detected in the stools of 89 (60.5%) children and 15 (10) patients had multiple agents detected. Rotavirus was found in 43 (29.3%) of the children, with a spring and winter peak in occurrence. Giardia lamblia was identified in 22 (15%) cases with a spring peak. HEp-2 cell-adherent E. coli were found in 15 (10.2%). Other agents found included: enteric adenovirus in 7 (4.8%); Salmonella in 5 (3.4%); enterohemorrhagic E. coli in 5 (3.4%); enteropathogenic E. coli in 2 (1.4%); enterotoxigenic E. coli in 2 (1.4%); Entamoeba histolytica in 1 (0.70%); and Campylobacter jejuni in 1 (0.7%).

CONCLUSIONS

In addition to the presence of conventional enteropathogens, diarrheagenic E. coli (HEp-2 cell-adherent E. coli, enterohemorrhagic E. coli, enteropathogenic E. coli and enterotoxigenic E. coli) were associated with endemic pediatric diarrhea in the US.

Combined carotid endarterectomy and coronary artery bypass: immediate and long-term results

Data from 213 cases of simultaneous carotid endarterectomy and coronary artery bypass grafting (CEN/CABG) were analyzed (1980-1996). There were 154 males (72.3%), and 59 females (27.7%), (mean age: 65. 6 years, range: 42-83). One hundred and thirty-two patients (62.0%) had angina, 58 (37.2%) had myocardial infarction, and 23 (10.8%) had congestive heart failure. Symptomatic cerebrovascular disease was present in 89 patients (41.7%). One hundred and twenty-two patients (57.2%) had three-vessel coronary artery disease, 41 (19.2%) had left main disease, and 27 (12.6%) had a low ejection fraction (ejection fraction </=30%). Significant (>/=75% diameter reduction) stenosis was present in 168 (78.8%) of the operated carotid arteries. The contralateral internal carotid artery was severely stenosed or occluded in 35 patients (16.4%). The hospital mortality rate was 5. 6% (12 patients). The cause of death was cardiac in ten patients (4. 6%), and neurologic in two (1%). Eleven patients (5.1%) developed a stroke postoperatively; eight strokes were ipsilateral to the operated artery, and six were permanent. Myocardial infarction occurred in five patients (2.3%). Independent predictors of early mortality were age >62 years, hypertension, and postoperative stroke (p < 0.05). Male sex was the only independent predictor of neurologic morbidity (p < 0.05). Late follow-up data were obtained for 163 (81.0%) patients (mean: 54.8 months, range: 1-168). Four (9. 3%) out of the 43 late deaths were attributed to strokes. There were three (1.8%) late ipsilateral strokes, and five (3.1%) contralateral strokes. The 5- and 10-year survival probabilities were 75 +/- 4%, and 52 +/- 6.9%. The freedom from late ipsilateral neurologic morbidity at 5 and 10 years were 97 +/- 1.7% and 90 +/- 4.0%, respectively. Taken together, the results indicate that combined carotid endarterectomy and coronary artery bypass grafting can be performed safely in this high-risk group of patients. Excellent long-term freedom from stroke can be expected.

Rifaximin: a nonabsorbed antimicrobial in the therapy of travelers' diarrhea

BACKGROUND/AIMS

Bacterial enteropathogens, the major cause of travelers' diarrhea, are customarily treated with antibacterial drugs. Rifaximin, a nonabsorbed antimicrobial was examined as treatment for travelers' diarrhea.

METHODS

A randomized, prospective, double-blind clinical trial was carried out in 72 US adults in Mexico. Patients with acute diarrhea received one of three doses of rifaximin (200, 400 and 600 mg t.i.d.) or trimethoprim/sulfamethoxazole (TMP/SMX, 160 mg/800 mg b.i.d.) for 5 days. Results were compared with data from 2 placebo-treated historical control populations.

RESULTS

The shortest duration of treated diarrhea was seen in the group receiving 200 mg rifaximin t. i.d (NS). Clinical failure to respond to treatment occurred in 6 of 55 (11%) rifaximin-treated subjects versus 5 of 17 (29%) of TMP/SMX-treated subjects (NS). Sixteen of twenty (80%) of the enteropathogens isolated from the rifaximin-treated subjects and 7 of 7 (100%) from the TMP/SMX group were eradicated by treatment (NS). Sixteen of twenty-four (67%) enteropathogens identified were susceptible to TMP and all 24 were inhibited by</=50 microgram/ml of rifaximin. Rifaximin reduced the number of unformed stools passed during the first 24 h of treatment when compared with 2 control placebo groups (3.3 versus 5.1; p = 0.008 and 0.0001) and led to a reduced duration of post-enrollment diarrhea (mean values of 43.1 versus 68.1 and 81.9 h; p = 0.001).

CONCLUSIONS

Rifaximin shortened the duration of travelers' diarrhea compared with TMP/SMX and 2 earlier studied placebo-treated groups. A poorly absorbed drug if effective in treating bacterial diarrhea has pharmacologic and safety advantages over the existing drugs.

Immaturity of electrophysiological response of the neonatal auditory brainstem to high repetition rates of click stimulation

Changes in brainstem auditory evoked response (BAER) with varying stimulus repetition primarily represent neural processes concerning the efficacy of synaptic transmission in the brainstem auditory pathway. In this study the BAER to different rates of clicks was recorded from 16 term neonates. The results were compared with those from 16 adults to examine whether the degree of maturation of synaptic transmission of the neonatal brainstem auditory pathway parallels that of general function of the pathway. All BAER wave latencies and interpeak intervals increased linearly and wave amplitudes reduced with increasing click rate. The absolute rate-dependent changes in BAER measures were much greater in the neonates than in the adults, reflecting a significant immaturity in the efficacy of synaptic transmission in the neonatal auditory brainstem and in the ability of the neonatal brainstem to process rapid acoustic stimulation. When the data obtained at higher click rates at various age groups were analyzed as percentages, using the BAER measurements at conventionally used slow rate (21/s) of clicks as the denominators, the changing rates (%), or relative changes, of most BAER measures at higher rates in the neonates were still greater than those in the adults. Therefore, the rate-dependent BAER changes in the neonates are relatively less mature than general aspects of the BAER, reflected by the BAER elicited with conventionally used slow rates of clicks. These findings suggest that synaptic efficacy in the neonatal brainstem auditory pathway is relatively less mature than general function of the pathway and thus may be more susceptible to unfavourable perinatal conditions.

Screening systems for detecting inhibitors of cell wall transglycosylation in Enterococcus. Cell wall transglycosylation inhibitors in Enterococcus

We devised two screening systems to detect cell wall transglycosylation inhibitors. One screen utilizes a mutant of Enterococcus faecalis strain A256 that is dependent on vancomycin or moenomycin for growth. In the absence of transglycosylation inhibitors the strain fails to grow, while in the presence of inhibitors, cells are rescued. A second screening organism E. faecalis strain MDD212 utilizes a translational fusion of the lacZ gene to the vanH promoter in a derivative of E. faecalis that contains a vancomycin resistance determinant. Induction of beta-galactosidase occurs when cells are exposed to inhibitors of transglycosylation. Our natural products drug source of fungal fermentations was tested with these screens. Several cultures that produced the same family of compounds, called the thielavins, were detected. Thielavin B inhibited the formation of peptidoglycan in an in vitro assay, suggesting that these screening systems can detect compounds that interfere with cell wall transglycosylation.

Maturation of peripheral and brainstem auditory function in the first year following perinatal asphyxia: a longitudinal study

Maturation of peripheral hearing and auditory brainstem following perinatal asphyxia was investigated by longitudinal recording of brainstem auditory evoked potentials (BAEP) during the first year of life in affected infants. The general maturational course of the BAEP following asphyxia was similar to that in a control group of infants with normal births, although there were some abnormalities in the BAEP Response threshold elevation seen in a few asphyxiated infants improved significantly during the first 3 months. The interpeak intervals in the asphyxiated infants did not differ significantly from that of the control-group infants except in the first month, when the I-V and III-V intervals were significantly prolonged in the severe asphyxia group. In contrast, wave V amplitude and V/I ratio were always smaller when compared to that of the control-group infants. Amplitude reduction of wave V was more sustained than the prolonged I-V interval. Persistent hearing loss and brainstem auditory impairment were seen in 6.8% and 14.6% of the asphyxiated infants, respectively. These findings suggest that asphyxia does not interfere significantly with the maturation of the auditory system in most asphyxiated infants and that sustained peripheral hearing loss and brainstem impairment occur only in a small proportion of affected infants.

Auditory brainstem projections to the ferret superior colliculus: anatomical contribution to the neural coding of sound azimuth

The mammalian superior colliculus (SC) contains a neural map of auditory space. It is not known whether this topographic representation emerges at the level of the SC or is relayed there from other auditory areas. We have used retrograde labelling techniques in ferrets to examine the sources and pattern of innervation from auditory brainstem nuclei. After multiple injections of wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) into the SC, the heaviest concentrations of labelled cells were found in the nucleus of the brachium (BIN) and external nucleus of the inferior colliculus, with much weaker labelling in the nucleus sagulum, dorsal, intermediate and ventral nuclei of the lateral lemniscus, paralemniscal regions, and periolivary nuclei. The projections were predominantly ipsilateral, although labelled cells were found on both sides of the brainstem. Single injections of WGA-HRP or discrete injections of red and green latex microspheres revealed that the caudal and lateral regions of the SC receive the heaviest projections, although the majority of the retrogradely labelled neurons in the contralateral BIN project to rostral SC. On the ipsilateral side, neurons in rostral and caudal regions of the BIN were labelled primarily by the tracer injected into rostral and caudal regions of the SC, respectively. However, no clear segregation was apparent in the BIN after injections into the medial and lateral regions or in any of the other nuclei after either injection paradigm. These data suggest that converging inputs from several auditory brainstem nuclei contribute to the construction of the auditory space map in the SC, although information about sound azimuth may be conveyed to this nucleus via a spatially ordered projection from the ipsilateral BIN.

HEp-2 cell-adherent Escherichia coli and intestinal secretory immune response to human immunodeficiency virus (HIV) in outpatients with HIV-associated diarrhea

HEp-2 cell-adherent Escherichia coli and the human immunodeficiency virus (HIV) itself have recently been incriminated as causes of chronic HIV-associated diarrhea. This study sought to determine the prevalence of these two agents among HIV-infected patients with diarrhea in an outpatient setting in the United States and to compare their prevalence to that of other commonly recognized enteropathogens known to be present in this population. HEp-2 cell-adherent E. coli was found in 20 of 83 (24.1%) patients with diarrhea. A diffuse pattern of adherence was the most common, found in 14 of 20 (70%) patients, followed by a localized adherence pattern (6 of 20; 30%). An intestinal secretory immune response against the p24 antigen of HIV was found in 9 of 34 (27.5%) patients with HIV-associated diarrhea. The following pathogens or products were also detected in lower frequencies: Cryptosporidium spp. (10.8%), Clostridium difficile toxin (8.8%), microsporidia (6%), Isospora belli (3.6%), Blastocystis hominis (2.4%), Giardia spp. (1.2%), Salmonella spp. (1.2%), and Mycobacterium spp. (1.2%). The role of HEp-2 cell-adherent E. coli and HIV enteric infections in patients with HIV-associated diarrhea deserves further study.

Sources of subcortical projections to the superior colliculus in the ferret

We have identified brainstem and other subcortical afferents to the superior colliculus (SC) in the ferret, by examining the pattern of retrograde labelling that resulted from unilateral injections of red and green fluorescent latex microspheres or of wheat germ agglutinin conjugated to horseradish peroxidase into different regions of this midbrain nucleus. Labelled neurons were found in many structures, including somatosensory, visual and auditory nuclei. These subcortical inputs are almost all bilateral, although most are primarily ipsilateral. Despite some differences in organization, the subcortical projections to the ferret SC broadly resemble those described in other species. Following injections of red and green microspheres in either the rostral and caudal or the medial and lateral regions of the SC, double-labelled cells usually accounted for less than 10% of the total number of retrogradely labelled cells, indicating that most of the subcortical neurons project to discrete regions of the SC. Many of these afferents show some topographic organization, which is much more evident along the rostrocaudal axis of the SC than in the medial-lateral dimension. The intercollicular projection is restricted mainly to the rostral SC and demonstrates a point-to-point organization. Most of the subcortical structures caudal to the central region of the SC were labelled mainly by the tracers injected in caudal SC, while those rostral to this region, including the zona incerta and the pretectal nuclei, were labelled largely by injections in rostral SC. These findings suggest that projections originating from nuclei posterior to the central region of the SC terminate principally in caudal SC whereas afferents from structures anterior to the central region project largely to rostral SC.

Continuous electroencephalographic monitoring and selective shunting reduces neurologic morbidity rates in carotid endarterectomy

PURPOSE

The role of continuous electroencephalographic (EEG) monitoring during carotid endarterectomy was evaluated in this retrospective review.

METHODS

We analyzed data from 902 consecutive carotid endarterectomy procedures performed with vein patch angioplasty. In 591 operations from 1980 to 1988 we did not use intraoperative EEG monitoring or shunting (non-EEG group). Continuous intraoperative EEG monitoring and selective shunting were used in 311 procedures from 1988 to 1994 (EEG group). The patients' mean age was higher in the EEG group (68.8 years; range, 41 to 87 years) than in the non-EEG group (66.2 years; range, 34 to 90 years; p < 0.001). There was also a significantly higher incidence of hypertension (56.2% vs 41.9%) and redo operations (5.4% vs 2.54%) in the EEG group than in the non-EEG group (p < 0.05). The operative technique was identical in both groups. We defined a significant EEG change as a greater than 50% reduction of the amplitude of the faster frequencies, a persistent increase of delta activity, or both.

RESULTS

In the EEG group, acute EEG changes occurred in 40 patients (12.8%); 31 (77.5%) unilateral and ipsilateral to the operated carotid artery, and nine (22.5%) bilateral. In five patients (12.5%) the changes correlated with an intraoperative episode of hypotension, and after normal blood pressure was restored the EEG returned to normal. In 35 procedures (87.5%) a carotid shunt was inserted. In 33 of those patients the EEG returned to baseline, in one patient there was a significant improvement, and in one patient the EEG changes persisted. Postoperative hospital strokes occurred in one patient (0.32%) in the EEG group and in 13 patients (2.19%) in the non-EEG group (p < 0.05). All strokes (n = 14) were ipsilateral to the operated carotid artery. Of the 13 strokes in the non-EEG group nine were major and four were minor. The one stroke in the EEG group was embolic in origin and occurred before carotid cross-clamping; it was associated with profound EEG changes that did not reverse after placement of a shunt. In the total group (n = 902), intraoperative EEG monitoring was inversely associated with postoperative stroke (p < 0.05).

CONCLUSION

The overall neurologic morbidity rate was significantly lower in the EEG group than in the non-EEG group, therapy demonstrating the value of intraoperative EEG monitoring in carotid endarterectomy.

Novel oxylipins from the temperate red alga Polyneura latissima: evidence for an arachidonate 9(S)-lipoxygenase

The oxylipin chemistry of the temperate red alga Polyneura latissima has been investigated. The structures of three novel oxylipins, 8-[1'(Z),3'(Z),6'(Z)-dodecatriene-1'-oxy]- 5(Z),7(E)-octadienoic acid, 7(S*)-hydroxy-8(S*),9(S*)-epoxy-5(Z),11(Z),14(Z)-eicosatrienoic acid, 7(R*)-hydroxy-8(S*),9(S*)-epoxy-5(Z),11(Z),14(Z)-eicosatrienoic acid, together with two known eicosanoids, 9(S)-hydroxy-5(Z),7(E),11(Z),14(Z)-eicosatetraenoic acid, and 9,15-dihydroxy-5(Z),7(E),11(Z),13(E)-eicosatetraenoic acid, were elucidated by spectroscopic methods and chemical degradation. The oxygenation pattern of these oxylipins suggests that P. latissima metabolizes polyunsaturated fatty acids via a 9(S)-lipoxygenase.

Topographic organization of projection from the parabigeminal nucleus to the superior colliculus in the ferret revealed with fluorescent latex microspheres

Unilateral, discrete injections of red and green fluorescent latex microspheres or injections of wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) were made into the ferret's superior colliculus (SC) to characterize the topographic organization of the projection from the parabigeminal nucleus (PBN). Retrograde labelling in the PBN revealed that this nucleus projects bilaterally to the SC, although the heaviest projection arises from the ipsilateral PBN. The PBN-SC projection demonstrates a highly ordered organization along the rostral-caudal axis; rostral PBN projects to rostral SC and caudal PBN projects to caudal SC. The caudoventral and rostrodorsal areas of the PBN project mainly to the ipsilateral and contralateral SC, respectively. The ipsilateral pathway terminates principally in the caudal region of the SC, while the contralateral projection terminates predominantly in rostral SC. Ipsilaterally, there are slightly more neurons, located mainly in the ventral PBN, that project to the lateral SC than those, located largely in the dorsal part of the nucleus, that target the medial SC. The contralateral PBN mainly projects to the rostrolateral quadrant of the SC. These results indicate that each quadrant of the SC is innervated principally by a restricted part of the PBN: the caudolateral quadrant, which receives the heaviest ipsilateral input, and the caudomedial quadrant are targeted predominantly by the ventral and dorsal portions, respectively, of the ipsilateral PBN; the rostrolateral quadrant by the contralateral PBN, and the rostromedial quadrant, which receives the weakest input, by the dorsal portion of the nucleus on both sides. These findings suggest that activity in the PBN is relayed to distinct regions of the SC in the form of a highly ordered topographic projection. The adjacent lateral tegmentum (ALT) also projects heavily to the SC, principally on the ipsilateral side. The ALT projection to the ipsilateral SC appears to be organized in a less orderly fashion, and terminates principally in caudal SC, particularly the caudolateral quadrant. No topography was apparent for the contralateral projection.