Technical details of sentinel lymph node mapping in colorectal cancer and its impact on staging

BACKGROUND

Sentinel lymph node (SLN) mapping for melanoma and breast cancer has greatly enhanced the identification of micrometastases in many patients, thereby upstaging a subset of these patients. The purpose of this study was to see if SLN mapping technique could be used to identify SLNs in colorectal cancer and to assess its impact on pathological staging and treatment.

METHODS

At the time of surgery, 1 ml of Lymphazurin 1% was injected subserosally around the tumor without injecting into the lumen. The first to fourth blue nodes identified were considered the SLNs, which have the highest probability to contain metastases. A standard oncological resection of the bowel was then performed. Multilevel microsections of the SLNs, including a detailed pathological examination of the entire specimen, was performed.

RESULTS

SLN was successfully identified in 85 (98.8%) of 86 patients. In 85 patients, there were 1,367 (16 per patient) lymph nodes examined, of which 140 (1.6 per patient) were identified as SLNs. In 53 (95%) of 56, of whom the SLNs were without metastases (negative), all other non-SLNs also were negative. In 29 (34% of 85) patients, SLNs were positive for metastases; in 14 of the 29 patients, other non-SLNs also were positive in addition to the SLNs. In the other 15 of the 29 patients (18% of 85 patients), SLNs were the only site of metastases, and all other non-SLNs were negative. In 7 patients (8.2% of 85 patients), micrometastases were identified only in 1 or 2 of the 10 sections of a single SLN. In five of seven patients, such micrometastases were detected by hematoxylin and eosin staining and immunohistochemistry; in the other two patients, it was detected only by immunohistochemistry. In patients with negative SLNs, the rate of occurrence of micrometastases in non-SLNs was 5 (0.4%) of 1,184 lymph nodes.

CONCLUSIONS

SLN mapping can be performed easily in colorectal cancer patients, with an accuracy of more than 95%. The identification of submicroscopic lymph node metastases by this technique may have upstaged these patients (18%) from stage I/II to stage III disease, who may then benefit from further adjuvant chemotherapy.

Chronic pulmonary function impairment caused by initial and recurrent pulmonary tuberculosis following treatment

BACKGROUND

A study was undertaken to establish the chronic effect of initial and recurrent treated pulmonary tuberculosis on impairment of lung function.

METHODS

A total of 27 660 black South African gold miners who had reliable pulmonary function tests from January 1995 to August 1996 were retrospectively followed for the incidence of pulmonary tuberculosis to 1970. The lung function measurements in 1995-6 were related to the number of previous episodes of tuberculosis and to the time that had lapsed from the diagnosis of the last episode of tuberculosis to the lung function test. Miners without tuberculosis or pneumoconiosis served as a comparison group.

RESULTS

There were 2137 miners who had one episode of tuberculosis, 366 who had two, and 96 who had three or more episodes. The average time between the diagnosis of the last episode of tuberculosis and the lung function test was 4.6 years (range one month to 31 years). The loss of lung function was highest within six months of the diagnosis of tuberculosis and stabilised after 12 months when the loss was considered to be chronic. The estimated average chronic deficit in forced expiratory volume in one second (FEV(1)) after one, two, and three or more episodes of tuberculosis was 153 ml, 326 ml, and 410 ml, respectively. The corresponding deficits for forced vital capacity (FVC) were 96 ml, 286 ml, and 345 ml. The loss of function due to tuberculosis was not biased by the presence of HIV as HIV positive and HIV negative subjects had similar losses. The percentage of subjects with chronic airflow impairment (FEV(1) <80% predicted) was 18.4% in those with one episode, 27.1% in those with two, and 35.2% in those with three or more episodes of tuberculosis.

CONCLUSIONS

Tuberculosis can cause chronic impairment of lung function which increases incrementally with the number of episodes of tuberculosis. Clearly, prevention of tuberculosis and its effect on lung function is important and can be achieved by early detection and by reduction of the risk of tuberculosis through intervention on risk factors such as HIV, silica dust exposure, silicosis, and socioeconomic factors.

A selective N-type calcium channel antagonist protects against neuronal loss after global cerebral ischemia

Calcium influx is believed to play a critical role in the cascade of biochemical events leading to neuronal cell death in a variety of pathological settings, including cerebral ischemia. The synthetic omega-conotoxin peptide SNX-111, which selectively blocks depolarization-induced calcium fluxes through neuronal N-type voltage-sensitive calcium channels, protected the pyramidal neurons in the CA1 subfield of the hippocampus from damage caused by transient forebrain ischemia in the rat model of four-vessel occlusion. SNX-111 provided neuroprotection when a single bolus injection was administered intravenously up to 24 hr after the ischemic insult. These results suggest that the window of opportunity for therapeutic intervention after cerebral ischemia may be much longer than previously thought and point to the potential use of omega-conopeptides and their derivatives in the prevention or reduction of neuronal damage resulting from ischemic episodes due to cardiac arrest, head trauma, or stroke. Microdialysis studies showed that SNX-111 was 3 orders of magnitude less potent in blocking potassium-induced glutamate release in the hippocampus than the conopeptide SNX-230, which, in contrast to SNX-111, failed to show any efficacy in the four-vessel occlusion model of ischemia. These results imply that the ability of a conopeptide to block excitatory amino acid release does not correlate with its neuroprotective efficacy.

TGF-beta1 DNA polymorphisms, protein levels, and blood pressure

Transforming growth factor-beta1 (TGF-beta1), a multifunctional cytokine with fibrogenic properties, has been implicated in the pathogenesis of the vascular and target organ complications of hypertension. TGF-beta1 may also regulate blood pressure via stimulation of endothelin-1 and/or renin secretion. Herein we explored the hypothesis that circulating levels of TGF-beta1 protein (quantified using a TGF-beta1-specific sandwich ELISA) are correlates of blood pressure levels. This hypothesis was tested in 98 stable end-stage renal disease (ESRD) patients. (The use of ESRD patients as the study cohort eliminates renal function-dependent alterations in circulating levels of TGF-beta1 protein.) In addition, in view of the previously reported correlation among TGF-beta1 DNA polymorphisms and systolic blood pressure, TGF-beta1 codon 25 genotype and alleles were identified in 71 hypertensive subjects and 57 normotensives using amplification refractory mutation system polymerase chain reaction. Our studies demonstrate for the first time that TGF-beta1 levels (209+/-13 ng/mL, mean+/-SEM) are positive correlates (Pearson correlation analysis) of mean arterial pressure (P=0.008), systolic pressure (P=0.02), and diastolic pressure (P=0. 01). We also report that a higher percentage of hypertensives (92%) compared with normotensives (86%) are homozygous for the arginine allele at codon 25. Our observations support the idea that genetically determined TGF-beta1 protein concentrations may play a role in blood pressure regulation in humans.

Successful transplantation of adult-sized kidneys into infants requires maintenance of high aortic blood flow

BACKGROUND

Nationally, results of renal transplantation in infants are inferior to those in older children and adults. Within the infant group, best results are obtained with adult-sized kidneys (ASKs) rather than size-compatible pediatric kidneys. However, transplantation of ASKs into infants has an increased risk of acute tubular necrosis and graft loss from vascular thrombosis and primary nonfunction. The aim of this study was to define and understand the hemodynamic changes induced by ASK transplantation, so that outcomes of transplantation in infants can be improved.

METHODS

Nine hemodynamically stable and optimally hydrated infants were studied under a controlled sedation with cine phase-contrast magnetic resonance at three time periods: before transplantation, 8-12 days after transplantation, and 4-6 months after transplantation. Cross-sectional images of both the infant aorta and the adult transplant renal artery were obtained and blood flow was quantitated. Renal volumes were also obtained, and expected renal artery blood flow based on early posttransplant volume was calculated. In addition, renal artery blood flow was determined in 10 in situ native adult kidneys prior to donor nephrectomy. Supplemental nasogastric or gastrostomy tube feeding was carried out during the blood flow study period to optimize intravascular volume.

RESULTS

Mean infant aortic blood flows were 331+/-148 ml/min before transplantation, 761+/-272 ml/ min at 8-12 days after transplantation (P=0.0006 with pretransplant flow), and 665+/-138 ml/min at 4-6 months after transplantation (P=0.0001 with pretransplant flow). Mean transplanted renal artery flows were 385+/-158 ml/min at 8-12 days and 296+/-113 ml/min at 4-6 months after transplantation. Transplanted renal artery flows were less than prenephrectomy in situ donor renal artery blood flow (618+/-130 ml/min; P=0.02 and P=0.0003) and expected normal renal artery blood flow (666+/-87 ml/min; P=0.003 and P=0.001) at both 8-12 days and 4-6 months after transplantation. A 26% reduction in renal volume (P=0.003) occurred between the two postoperative time periods, and this paralleled the decrease in posttransplant renal artery flow. One-year graft and patient survival in the nine infants was 100%. The mean serum creatinine levels at 3, 6, and 12 months were 0.43+/-0.10, 0.48+/-0.15, and 0.49+/-0.16 mg/dl.

CONCLUSIONS

This study is the first to quantitatively document the blood flow changes occurring after ASK transplantation in infants. There was a greater than two-fold increase in aortic blood flow after ASK transplantation, and this increase was sustained for at least 4 months and appeared to be driven by the blood flow demand of the ASK. However, actual posttransplant renal artery blood flow was significantly less than normal renal artery flow. Our study suggests that aggressive intravascular volume maintenance may be necessary to achieve and maintain optimum aortic blood flow, so as not to further compromise posttransplant renal artery flow and to avoid low-flow states that could induce acute tubular necrosis, vascular thrombosis, or primary nonfunction.

Effects of backpack load position on spatiotemporal parameters and trunk forward lean

Backpack loads for school children have increased over the last two decades raising concerns among medical practitioners and parents about the possible detrimental effects. Gait instability induced due to backpack load carriage is of concern especially for young children with insufficient motor control skills to resist falls. The present study investigated the impact of backpack load carriage and its vertical position on the back on temporal-spatial and kinematic parameters associated with gait and postural stability for static and dynamic conditions. 17 participants with mean age 9.65 (+/-1.58) years, mean height 134.41 (+/-11.01) cm and mean mass 31.09 (+/-7.01) kg participated in the study. For dynamic conditions, the participants walked on an instrumented treadmill with 10%, 15% and 20% bodyweight (BW) loads on two locations on the back. Kinematic and temporal-spatial data was collected on the participants. Walking velocity, cadence and double support time for 20% load condition were significantly different compared to the unloaded condition indicating that gait changes may have occurred to minimize gait destabilization. Placing load low on the back affected the spatiotemporal parameters more than when loads were placed high on the back. The findings on spatiotemporal parameters indicate that a reduction in gait velocity and cadence and an increase in double support time for the 20% lower configuration could be a compensatory mechanism for children to minimize either the induced gait instability or mechanical strain on the musculoskeletal system in terms of possible higher lower limb joint moments or both. Results also showed higher forward trunk lean for dynamic conditions compared to static conditions indicating differences in strategies employed to maintain balance for static and dynamic conditions.

Transforming growth factor-beta 1 hyperexpression in African American end-stage renal disease patients

End-stage renal disease (ESRD) is more frequent in African Americans (blacks) compared to Caucasian Americans (whites). Identification of remediable causes of the increased prevalence has the potential to reduce the excess burden of ESRD. Because renal fibrosis is a correlate of progressive renal failure and a dominant feature of ESRD, and because transforming growth factor-beta 1 (TGF-beta 1) can induce fibrosis and renal insufficiency, we explored the hypothesis that TGF-beta 1 hyperexpression is more frequent in black ESRD patients compared to white ESRD patients. Our postulate was tested by determining circulating levels of TGF-beta 1 protein in the sera of 56 black and 42 white ESRD patients treated by chronic hemodialysis. A solid-phase sandwich enzyme-linked immunosorbent assay, specific for TGF-beta 1, was used to quantify TGF-beta 1 levels in the ESRD cohort. Additional cytokines implicated in tissue repair/remodeling, interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha), were also measured. Our investigation demonstrated a significantly higher concentration of TGF-beta 1 protein but not that of IL-6 or TNF-alpha in blacks compared to whites. Our observation that TGF-beta 1 is hyperexpressed in black ESRD patients suggests a mechanism for the increased prevalence of renal failure (since TGF-beta 1 hyperexpression can result in renal insufficiency in experimental models) among the black population.

Advancing the spontaneous hypertensive rat model of attention deficit/hyperactivity disorder

To advance the spontaneous hypertensive rat (SHR) model of attention deficit/hyperactivity disorder (ADHD), experiments examined the SHR in tasks recognized to assess functioning of the prefrontal cortex or dorsal striatal. Tasks included odor-delayed win-shift (nonspatial working and reference memory), win-stay (habit learning), and attentional set-shifting (attention and behavioral flexibility). In Experiment 1, the SHR strain was compared with Wistar-Kyoto (WKY) and Wistar-Kyoto Hypertensive (WKHT) strains on the first 2 tasks. In Experiment 2, oral methylphenidate (1.5 mg/kg) and vehicle (water) were evaluated on all 3 tasks in SHR and WKY strains. Results demonstrated that the SHR made significantly more errors in the odor-delayed win-shift, win-stay, and attentional set-shifting tasks compared with the WKY. Similar performances in the WKY and WKHT indicated that deficits observed in the SHR were not related solely to hypertension. Treating the SHR with methylphenidate eliminated strain differences in all 3 tasks. These findings provide evidence that the SHR is a valid model for studying ADHD-associated neurocognitive deficits. Moreover, the current behavioral approach is appropriate to assess novel medications developed to target ADHD-associated neurocognitive deficits.

Declining HIV/AIDS mortality in New York City

BACKGROUND

New York City has only 3% of the U.S. population but has reported nearly 16% of all AIDS cases.

METHODS

This is an observational study using the New York City vital events and AIDS case surveillance registries to describe trends in HIV/AIDS mortality from 1983 through June 30, 1998.

RESULTS

Annual HIV/AIDS deaths increased steadily until stabilizing at 7046 in 1995, declined 29% to 4998 in 1996, and declined 47% to 2625 in 1997. Comparing data from 1997 with those from 1995, declines occurred in all demographic groups and in all major HIV transmission categories: 74% in men who have sex with men, 68% in injecting drug users, and 64% in heterosexuals. In the first 6 months of 1998, declines were smaller than they had been in previous 6-month intervals in all demographic groups except Hispanic males and those between 35 and 44 years of age. From 1995 to the first 6 months of 1998, the number of people living with AIDS in New York City increased 22% (from 32,692 to 39,976).

CONCLUSIONS

The precipitous 63% decline in HIV/AIDS deaths from 1995 to 1997 occurred at the same time that more effective antiretroviral therapies became widely available. The slowing in the mortality decline observed in 1998, however, suggests that although these new therapies may have a profound effect at the population level, deaths due to AIDS will continue.

Fatigue and motor redundancy: adaptive increase in finger force variance in multi-finger tasks

We studied the effects of fatigue of the index finger on indices of force variability in discrete and rhythmic accurate force production tasks performed by the index finger and by all four fingers pressing in parallel. An increase in the variance of the force produced by the fatigued index finger was expected. We hypothesized that the other fingers would also show increased variance of their forces, which would be accompanied by co-variation among the finger forces resulting in relatively preserved accuracy of performance. The subjects performed isometric tasks including maximal voluntary contraction (MVC) and accurate force production before and after a 1-min MVC fatiguing exercise by the index finger. During fatigue, there was a significant increase in the root mean square index of force variability during accurate force production by the index finger. In the four-finger tasks, the variance of the individual finger force increased for all four fingers, while the total force variance showed only a modest change. We quantified two components of variance in the space of hypothetical commands to fingers, finger modes. There was a large increase in the variance component that did not affect total force and a much smaller increase in the component that did. The results suggest an adaptive increase in force variance by nonfatigued elements as a strategy to attenuate effects of fatigue on accuracy of multi-element performance. These effects were unlikely to originate at the level of synchronization of motor units across muscle compartments but rather involved higher control levels.

Warfarin use and the risk of valvular calcification

BACKGROUND

Warfarin affects the synthesis and function of the matrix Gla-protein, a vitamin K-dependent protein, which is a potent inhibitor of tissue calcification.

OBJECTIVES

To investigate the incidence of mitral valve calcium (MVC), mitral annular calcium (MAC) and aortic valve calcium (AVC) in patients with non-valvular atrial fibrillation (AF) treated with warfarin vs. no warfarin.

PATIENTS AND METHODS

Of 1155 patients, mean age 74 years, with AF, 725 (63%) were treated with warfarin and 430 (37%) without warfarin. The incidence of MVC, MAC and AVC was investigated in these 1155 patients with two-dimensional echocardiograms. Unadjusted logistic regression analysis was conducted to examine the association between the use of warfarin and the incidence of MVC, MAC or AVC. Logistic regression analyses were also conducted to investigate whether the relationship stands after adjustment for confounding risk factors such as age, sex, race, ejection fraction, smoking, hypertension, diabetes, dyslipidemia, coronary artery disease (CAD), glomerular filtration rate, calcium, phosphorus, calcium-phosphorus product, alkaline phosphatase, use of aspirin, beta blockers, angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, and statins.

RESULTS

There was a significant association between the use of warfarin and the risk of calcification [unadjusted odds ratio = 1.71, 95% CI = (1.34-2.18)]. The association still stands after adjustment for confounding risk factors. MVC, MAC or AVC was present in 473 of 725 patients (65%) on warfarin vs. 225 of 430 patients (52%) not on warfarin (P < 0.0001). Whether this is a causal relationship remains unknown.

CONCLUSIONS

Use of warfarin in patients with AF is associated with an increased prevalence of MVC, MAC or AVC.

Isolation of pathogenic Legionella species and legionella-laden amoebae in dental unit waterlines

Legionella released into the air during treatment are a potential source of infection. Water stagnation in dental unit waterlines (DUWLs) creates biofilms and promotes the proliferation of these micro-organisms. This study investigated the presence of amoeba infected with legionella, L. pneumophila and other pathogenic Legionella species in a dental teaching hospital. Water samples were collected in the morning and afternoon from 99 dental units and 16 taps connected to the municipal water supply. Samples were plated on selective media and tested for legionella using the direct immunofluorescent antibody technique and the latex agglutination test. Legionella were found in 33% of the DUWLs and in 47% of the mains taps supplying these units. Legionella-laden amoebae occurred in one mains tap sample and in 20% of DUWLs in a clinic of the teaching hospital. L. micdadei was the predominant species isolated from this clinic. L. pneumophila serogroups 2-14 predominated in the mains water, whereas L. pneumophila serogroup 1 was found in approximately half of the contaminated DUWLs and mains taps irrespective of the time of sampling. Pathogenic Legionella species seeded by municipal water into DUWLs is a potential source of legionella infection for both dental personnel and patients during prolonged dental treatment. This problem is compounded by the presence of legionella-laden amoebae which may contain levels of organism well within the infective dose. The interaction of legionella with amoebae is an important ecological factor that may significantly increase the risk of legionellosis, and thus should be given further consideration in the refinement of risk assessment models.

Glucoregulatory hormones in man at high altitude

Concentrations of glucose, lactic acid, free fatty acid (FFA), insulin, cortisol and growth hormone (GH) in the blood were monitored in 15 euglycaemic men (sojourners, SJ) at sea level (SL) and while at altitudes of 3500 m and 5080 m, in acclimatised low landers (ALL) and in high altitude natives (HAN). In SJ, blood glucose and insulin concentrations showed a significant increase on the 3rd and 7th day after arrival at high altitude (HA), thereafter returning to sea level values and remaining the same during the entire period of their stay at 3500 m. Subsequently, on arrival at higher altitude (5080 m) the glucose concentrations again showed an increase over the preceding values and returned to SL values on day 41 while at 5080 m. A significant increase in cortisol concentrations was seen on day 3 after arrival at HA and the increased levels were maintained until day 21 at 3500 m. The cortisol concentrations on day 30 after arrival at 5080 m came down to SL values and remained unchanged thereafter. No appreciable change in GH and FFA was seen during the sojourn at HA. On the other hand, blood lactic acid concentration decreased significantly. There was no difference between the fasting glucose concentrations in ALL at 3500 m and in HAN at 3500 m and 4200 m compared to values of SJ at SL, whereas ALL at 4200 m had higher glucose values. Concentrations of plasma insulin and GH in ALL and HAN were higher than the values of SJ at SL, whereas cortisol values did not show any difference. These observations indicated that at HA the glucose values were high for the insulin concentration observed and might have been due to increased secretion of GH by the pituitary gland.

Crystal structure of mistletoe lectin I from Viscum album

The crystal structure of the ribosome-inactivating protein (RIP) mistletoe lectin I (ML-I) from Viscum album has been solved by molecular replacement techniques. The structure has been refined to a crystallographic R-factor of 24.5% using X-ray diffraction data to 2.8 A resolution. The heterodimeric 63-kDa protein consists of a toxic A subunit which exhibits RNA-glycosidase activity and a galactose-specific lectin B subunit. The overall protein fold is similar to that of ricin from Ricinus communis; however, unlike ricin, ML-I is already medically applied as a component of a commercially available misteltoe extract with immunostimulating potency and for the treatment of human cancer. The three-dimensional structure reported here revealed structural details of this pharmaceutically important protein. The comparison to the structure of ricin gives more insights into the functional mechanism of this protein, provides structural details for further protein engineering studies, and may lead to the development of more effective therapeutic RIPs.

Aging cohort of perinatally human immunodeficiency virus-infected children in New York City. New York City Pediatric Surveillance of Disease Consortium

BACKGROUND

New York City (NYC) pediatricians are now caring for fewer HIV-infected infants and more school age children and adolescents than earlier in the epidemic.

METHODS

Clinical, laboratory and demographic data were abstracted from medical records at 10 NYC centers participating in the CDC Pediatric Spectrum of HIV Disease project. Pediatric AIDS cases and HIV-related deaths reported to the NYC Department of Health were examined.

RESULTS

Median age of HIV-infected children in care increased from 3 years in 1989 to 1991 to 6 years in 1995 to 1998. The number of HIV-infected women giving birth in NYC declined 50% from 1990 to 1997 (1630 to 831); increasing numbers were identified prenatally (14% in 1989; 78% after 1995); and most received prenatal zidovudine prophylaxis (73% in 1997). Estimated perinatal transmission decreased to 10% by 1997. Improved identification of seropositive status in infants was associated with an increased proportion of infected infants receiving Pneumocystis carinii pneumonia (PCP) prophylaxis, 84% in 1997. AIDS free survival was longer for children born 1995 to 1998 than for those born before 1995, P = 0.004. In 1998 among children with advanced immunosuppression (CDC category 3), 66% were prescribed 3 or more antiretroviral medicines and 88% received PCP prophylaxis. Citywide AIDS cases and HIV-related deaths fell precipitously beginning in 1996.

CONCLUSIONS

Based on the observations of this study, the cohort of NYC HIV-infected children in care is aging, associated with a decline in new HIV infections, high rates of PCP prophylaxis and increased time to AIDS. Falling HIV-related deaths citywide support these observations.

The association between congenital syphilis and cocaine/crack use in New York City: a case-control study

From 1987 to 1989, an epidemic of congenital syphilis was observed in New York City. A case-control study was done to assess the association between various maternal risk factors and congenital syphilis. Independent of the effect of other factors, the odds of being exposed to cocaine were 3.9 times greater among cases than controls (95% confidence interval, 2.8-5.3). This study suggests that the epidemic of congenital syphilis may be related to the increase in cocaine/crack use among delivering mothers.

Bioavailability of Ziconotide in brain: influx from blood, stability, and diffusion

Ziconotide is a selective peptide antagonist of the N-type calcium channel currently in clinical trials for analgesia. Ziconotide reached a maximal brain concentration of between 0.003 and 0.006% of the injected material per gram of tissue at 3-20 min after i.v. injection, and this decayed to below 0.001%/g after 2 h. The structurally distinct conopeptide SNX-185 (synthetic TVIA) was considerably more persistent in brain after i.v. administration, with 0.0035% of the injected material present at 2-4 h after i.v. injection, and 0.0015% present at 24 h. Similar results (i.e. greater persistence of SNX-185) were obtained when the peptides were perfused through in vivo dialysis probes implanted into the hippocampus. Image analysis and serial sectioning showed that diffusion of Ziconotide in the extracellular fluid around the dialysis probe was minimal, with the peptide located within 1 mm of the probe after 2 h. In vitro diffusion through cultured bovine brain microvessel endothelial cells (BBMEC) verified that a close structural analog of Ziconotide (SNX-194) passed through this blood-brain barrier (BBB) model as expected for peptides of similar physical properties (permeability coefficient of 6.5 x 10(-4) cm/g). Passage from blood to brain was also verified by in situ perfusion through the carotid artery. A statistically greater amount of radioactivity was found to cross the BBB after perfusion of radioiodinated Ziconotide compared to [14C]inulin. Capillary depletion experiments and HPLC analysis defined the brain location and stability.

Interactions of the fucose-specific Pseudomonas aeruginosa lectin, PA-IIL, with mammalian glycoconjugates bearing polyvalent Lewisa and ABH blood group glycotopes

Pseudomonas aeruginosa Fuc > Man specific lectin, PA-IIL, is an important microbial agglutinin that might be involved in P. aeruginosa infections in humans. In order to delineate the structures of these lectin receptors, its detailed carbohydrate recognition profile was studied both by microtiter plate biotin/avidin-mediated enzyme-lectin-glycan binding assay (ELLSA) and by inhibition of the lectin-glycan interaction. Among 40 glycans tested for binding, PA-IIL reacted well with all human blood group ABH and Le(a)/Le(b) active glycoproteins (gps), but weakly or not at all with their precursor gps and N-linked gps. Among the sugar ligands tested by the inhibition assay, the Le(a) pentasaccharide lacto-N-fucopentaose II (LNFP II, Galbeta1-3[Fucalpha1-4]GlcNAcbeta1-3Galbeta1-4Glc) was the most potent one, being 10 and 38 times more active than the Le(x) pentasaccharide (LNFP III, Galbeta1-4 [Fucalpha1-3]GlcNAcbeta1-3Galbeta1-4Glc) and sialyl Le(x) (Neu5Acalpha2-3Galbeta1-4[Fucalpha1-3] GlcNAc), respectively. It was 120 times more active than Man, while Gal and GalNAc were inactive. The decreasing order of PA-IIL affinity for the oligosaccharides tested was: Le(a) pentaose > or = sialyl Le(a) tetraose > methyl alphaFuc > Fuc and Fucalpha1-2Gal (H disaccharide)>2'-fucosyllactose (H trisaccharide), Le(x) pentaose, Le(b) hexaose (LNDFH I) and gluco-analogue of Le(y) tetraose (LDFT)>H type I determinant (LNFP I)>Le(x) trisaccharide (Galbeta1-4[Fucalpha1-3]GlcNAc) > sialyl Le(x) trisaccharide >> Man >>> Gal, GalNAc, and Glc (inactive). The results presented here, in accordance with the crystal 3D structural data, imply that the combining site of PA-IIL is a small cavity-type best fitting Fucalpha1- with a specific shallow groove subsite for the remainder part of the Le(a) saccharides, and that polyvalent glycotopes enhance the reactivity. The Fuc > Man Ralstonia solanacearum lectin RSL, which resembles PA-IIL in sugar specificity, differs from it in it's better fit to the B and A followed by H oligosaccharides vs. Fuc, whereas, the second R. solanacearum lectin RS-IIL (the structural homologue of PA-IIL) binds Man > Fuc. These results provide a valuable information on PA-IIL interactions with mammalian glycoforms and the possible spectrum of attachment sites for the homing of this aggressive bacterium onto the target molecules. Such information might be useful for the antiadhesive therapy of P. aeruginosa infections.

Selective blockade of N-type voltage-sensitive calcium channels protects against brain injury after transient focal cerebral ischemia in rats

The neuroprotective efficacy of the selective N-type voltage-sensitive calcium channel blocker, SNX-111, was evaluated in spontaneously hypertensive rats subjected to 60 min of focal cerebral ischemia by permanent ligation of the right common carotid artery and temporary occlusion of the right middle cerebral artery. Intravenous infusion of 167 microg/kg per min SNX-111 for 30 min (5 mg/kg), initiated immediately after reperfusion, significantly reduced cortical infarct volumes measured 24 h after the ischemic insult.

A Multistate Model for the Fluorescence Response of R-Phycoerythrin

Although strong fluorescence makes the R-phycoerythrin (R-PE) proteins increasingly useful in biological and clinical assays, they are subject to nonlinear effects including transitions to collective dark states and photodegradation, which complicate quantitative applications. We report measurements of R-PE fluorescence intensity as a function of incident power, duration of illumination and temperature. Emission intensity in the band at 570 nm is proportional to incident power for low power levels. At higher incident power, the emission at 570 nm is smaller than expected from a linear dependence on power. We propose that R-PE undergoes both reversible emission cessation on a millisecond time scale attributed to transitions to a collective dark state, and irreversible photodegradation on a time scale of minutes. Singlet oxygen scavengers such as dithiothreitol and n-propyl gallate have protective effects against the latter effect but not the former. Electrophoretic analysis of irradiated solutions of R-PE indicates that significant noncovalent aggregation is correlated with photodegradation. A multistate model based on fluorescence measurements and geometric analysis is proposed for the fluorophores in R-PE. The phycobilin fluorophores are partitioned into three groups: the phycourobilins (PUB) absorbing at 490 nm, one group of phycoerythobilins (PEB) absorbing at 530 nm (PEB-530) and another group of PEB absorbing at 560 nm (PEB-560). The two processes that result in the loss of fluorescence intensity are most likely associated with the PEB-560 group.

Diabetes mellitus--a newly described risk factor for infection from Salmonella enteritidis

Infections due to Salmonella serotype enteritidis have increased markedly in the northeastern United States. Due to the potential severity of these infections, host risk factors for infection were determined in the largest nosocomial S. enteritidis outbreak to have occurred in the United States. In a case-control study, patients in a New York City hospital who developed infection after exposure to an S. enteritidis-contaminated meal were more likely to be medication-dependent diabetics than were those who did not develop infection (17/75 vs. 7/80, Mantel-Haenszel adjusted odds ratio = 3.1, 95% confidence interval = 1.1, 8.6). Proposed mechanisms for diabetes as a risk factor for infection include decreased gastric acidity in diabetic patients and an autonomic neuropathy of the small bowel that reduces intestinal motility and prolongs gastrointestinal transit time.

Recombinant cytomegalovirus glycoprotein gB (UL55) induces an autoantibody response to the U1-70 kDa small nuclear ribonucleoprotein

Human cytomegalovirus (CMV) infection can be life threatening in the immune compromised and is associated with congenital defects and / or mental retardation in the neonate. The demonstrated association between CMV infection and rheumatoid factor (RF) raised the possibility of an induction of an autoimmune response upon vaccination with a candidate CMV vaccine, glycoprotein gB (UL55). The antibody responses generated after injections of an adenovirus-gB construct (Ad-gB) were studied in autoimmune-prone (MRL/mpj) and normal (BALB.k, C3H, and BALB/c) mice. Enzyme-linked immunosorbent assay and immunoblot analyses were done to identify the autoantibodies produced following immunization. Immunization with Ad-gB induced a significant IgG anti-viral response in all strains tested (p < 0.0001) compared to phosphate-buffered saline or HeLa controls. Ad-gB induced a significant IgG autoantibody response (p > 0.005) to the U1-70 kDa spliceosome protein in both autoimmune and normal strains whereas immunization with recombinant human La/SS-B did not. Autoantibodies to U1-70 kDa are part of the anti-ribonucleoprotein response seen in systemic lupus erythematosus and mixed connective tissue disease. Low levels of IgG RF and anti-double-stranded DNA antibodies were also induced. This study raises concern that immunization with CMV gB in individuals genetically predisposed to autoimmunity could trigger the development or acceleration of an autoimmune disease.