Diabetic and idiopathic gastroparesis is associated with loss of CD206-positive macrophages in the gastric antrum.

BACKGROUND: Animal studies have increasingly highlighted the role of macrophages in the development of delayed gastric emptying. However, their role in the pathophysiology of human gastroparesis is unclear. Our aim was to determine changes in macrophages and other cell types in the gastric antrum muscularis propria of patients with diabetic and idiopathic gastroparesis. METHODS: Full thickness gastric antrum biopsies were obtained from patients enrolled in the Gastroparesis Clinical Research Consortium (11 diabetic, 6 idiopathic) and 5 controls. Immunolabeling and quantitative assessment was done for interstitial cells of Cajal (ICC) (Kit), enteric nerves protein gene product 9.5, neuronal nitric oxide synthase, vasoactive intestinal peptide, substance P, tyrosine hydroxylase), overall immune cells (CD45) and anti-inflammatory macrophages (CD206). Gastric emptying was assessed using nuclear medicine scintigraphy and symptom severity using the Gastroparesis Cardinal Symptom Index. RESULTS: Both diabetic and idiopathic gastroparesis patients showed loss of ICC as compared to controls (Mean [standard error of mean]/hpf: diabetic, 2.28 [0.16]; idiopathic, 2.53 [0.47]; controls, 6.05 [0.62]; P=.004). Overall immune cell population (CD45) was unchanged but there was a loss of anti-inflammatory macrophages (CD206) in circular muscle (diabetic, 3.87 [0.32]; idiopathic, 4.16 [0.52]; controls, 6.59 [1.09]; P=.04) and myenteric plexus (diabetic, 3.83 [0.27]; idiopathic, 3.59 [0.68]; controls, 7.46 [0.51]; P=.004). There was correlation between the number of ICC and CD206-positive cells (r=.55, P=.008). Enteric nerves (PGP9.5) were unchanged: diabetic, 33.64 (3.45); idiopathic, 41.26 (6.40); controls, 46.80 (6.04). CONCLUSION: Loss of antral CD206-positive anti-inflammatory macrophages is a key feature in human gastroparesis and it is associates with ICC loss.

Blood donors in Kenya: a comparison of voluntary and family replacement donors based on a population-based survey.

BACKGROUND AND OBJECTIVES: Blood safety and sufficiency are major challenges in Kenya and other sub-Saharan African countries forcing many countries to rely on family replacement donors (FRD). We analysed data from a national AIDS indicator survey to describe blood donors in Kenya and potential risks of transfusion transmissible infections (TTI) comparing voluntary donors and FRD. MATERIALS AND METHODS: A population-based, cross-sectional survey was conducted in 2007 among 15- to 64-year-olds. Consenting participants were interviewed about blood donation history and were tested for HIV, HSV-2 and syphilis. RESULTS: Of the 17,940 people surveyed, 445 (2·3%) reported donating blood in the prior 12 months. Sixty-four per cent were voluntary donors, and the rest were FRD. Compared to FRD, the majority of voluntary donors were <25 years old (59% versus 18%), from the highest wealth quintile (57% versus 42%) and single (64% versus 23%). In addition, voluntary donors were less likely to have been sexually active than replacement donors (43% versus 13%). HIV prevalence was lower among voluntary donors than among FRD (2·6% versus 7·4%, P-value=0·07). CONCLUSIONS: The majority of blood donors in Kenya are voluntary with lower potential risk of TTI.

Quantification of print, radio and television exposure among previous blood donors in Kenya: an opportunity for encouraging repeat donation in a resource-limited setting?

Blood services in sub-Saharan Africa experience blood shortages and low retention of voluntary, non-remunerated donors. To boost collections by encouraging repeat donations, the Kenya National Blood Transfusion Service is exploring the likelihood of reaching previous donors through targeted print, radio and television advertising. We analysed data from a national AIDS Indicator Survey to determine whether previous donors have significant exposure to media. Respondents reporting history of blood donation had significantly higher exposure to print, radio and television media than those without history of blood donation. Targeted media campaigns encouraging repeat donation are likely to reach previous donors even in resource-limited settings.

Laparoscopic conversion of vertical banded gastroplasty to a Roux-en-Y gastric bypass.

The vertical banded gastroplasty was the mainstay of bariatric surgery for over a decade. Though this procedure is now rarely performed many of these patients will present with failure or maladaptive eating and its sequelae. Some of these patients who demonstrate the motivation for lifestyle modification as well as many of these with complications will be candidates for revisional surgery. This article reviews the technical challenges in performing these revisions using minimally invasive techniques. In addition it reviews outcomes of laparoscopic conversion and tips for patient selection and success.

Incidence of human immunodeficiency virus among male-to-female transgendered persons in San Francisco.

OBJECTIVE: To estimate HIV incidence among male-to-female transgendered persons (MtF transgendered persons) who repeatedly tested for HIV antibodies at public San Francisco counseling and testing sites between July 1997 and June 2000. METHODS: HIV seroconversions were identified and person-time of observation were estimated using the date and result of the current test and the self-reported date and result of the previous test. Factors independently associated with HIV seroconversion were determined using multivariable proportional hazard analysis. RESULTS: HIV incidence was 7.8 per 100 person-years (95% confidence intervals [CI], 4.6-12.3) based on 13 seroconversions among 155 repeat testers with 167.7 person-years of observation. African-American race/ethnicity (adjusted relative hazard ratio [HR], 5.0; 95% CI, 1.5-16.2) and unprotected receptive anal intercourse (HR, 3.9; 95% CI, 1.2-13.1) were independent predictors of HIV seroconversion. CONCLUSIONS: HIV is currently spreading at an extremely high rate among MtF transgendered persons in San Francisco, especially those who are African Americans.

HIV incidence among repeat HIV testers at a county hospital, San Francisco, California, USA.

OBJECTIVES: To estimate HIV incidence, characterize correlates of HIV seroconversion, and monitor temporal trends in HIV transmission among patients repeatedly tested for HIV by a county hospital in San Francisco. DESIGN: Retrospective longitudinal study. METHODS: HIV incidence was retrospectively calculated among persons voluntarily tested for HIV antibody more than once at San Francisco's county hospital or one of its affiliated satellite community clinics between 1993 and 1999. Linkage of HIV test results in computerized databases identified "seroconverters" as individuals who had a negative antibody test followed by a positive test. The interval between tests was used as the person-time at risk. Cox proportional hazards analysis identified correlates of HIV seroconversion. RESULTS: A total of 84 HIV seroconversions were identified among 2893 eligible patients repeatedly tested for HIV antibody over a cumulative 5860 person-years (PYs) (incidence of 1.4 per 100 PYs, 95% confidence interval [CI]: 1.2-1.7). The majority of seroconversions (71 [84.5%]) were among injection drug users (IDUs) (incidence of 2.0 per 100 PYs, CI: 1.6-2.4). HIV incidence was highest among men who have sex with men (MSM) who were also IDUs (incidence of 3.8 per 100 PYs, CI: 2.7-5.1) and lowest among non-IDUs, heterosexual men, and non-IDU women (incidence of 0.3 per 100 PYs, CI: 0.1-0.6). In multivariate analysis, correlates of HIV seroconversion were age 25 to 29 years (hazard ratio [HR] = 3.9, CI: 2.4-6.3), MSM (HR = 2.9, CI: 1.9-4.4), and IDU (HR = 3.2, CI: 1.8-5.8). Overall, no temporal trend in annual HIV incidence was noted during the study period; however, HIV incidence among MSM IDUs increased from 2.9 per 100 PYs in 1996 to 4.7 per 100 PYs in 1998. CONCLUSIONS: The rate of seroconversion in this hospital and affiliated clinic population is unexpectedly high. Moreover, HIV transmission among IDU patients has not decreased over the last several years. The San Francisco county hospital provides a high-risk sentinel population to monitor emerging trends in HIV transmission, especially among IDUs, and presents multiple opportunities for prevention interventions, because these patients are being seen repeatedly by clinicians.

Binding specificity of polymyxin B, BPI, LALF, and anti-deep core/lipid a monoclonal antibody to lipopolysaccharide partial structures.

The deep core/lipid A (DCLA) region of gram-negative bacterial lipopolysaccharide (LPS) is common to most gram-negative pathogens and contains anionic phosphoryl groups plus numerous acyl chains as part of the toxic lipid A moiety. Several disparate agents that antagonize the effects of LPS exhibit extensive physicochemical similarities (hydrophobicity, cationic charge) within their binding domains. It is presumed that binding to the DCLA region by each of these antagonists-cross-reactive anti-LPS monoclonal antibodies (mAbs), polymyxin B (PmB), plus bactericidal permeability-increasing protein (BPI) and Limulus anti-LPS factor (LALF)-may be related to these properties. Therefore, we hypothesized that in addition to secondary and tertiary protein conformation, electrostatic interactions involving the negatively charged phosphoryl groups, hydrophobic interactions involving the acyl chains of lipid A, or both might be important factors that promote LPS antagonism. Binding of PmB, BPI, LALF, or anti-DCLA mAb 1B6 to Salmonella minnesota monophosphoryl lipid A (MPLA), diphosphoryl lipid A (DPLA), and Salmonella minnesota Re (which possess a common structural moiety, but vary considerably in structure and charge) was examined. Highly phosphorylated DNA and bovine serum albumin served as unrelated structural controls. BPI bound MPLA, which is hydrophobic and minimally charged, while mAb 1B6 bound anionic DNA; neither PmB nor LALF were reactive with MPLA or DNA. We surmised that hydrophobic interactions play a role in BPI binding to LPS, and although electrostatic interactions appear to be important for binding of mAb 1B6 to DCLA, they may not contribute to as great an extent for PmB, BPI, or LALF. Thus our data support the contention that the contribution of these specific physicochemical factors varies among endotoxin antagonists.

Bactericidal and endotoxin neutralizing activity of a peptide derived from Limulus antilipopolysaccharide factor.

BACKGROUND: Release of lipopolysaccharide (endotoxin, LPS) is a critical inciting event in the development of sepsis syndrome due to gram-negative bacteria, and mortality associated with this entity remains approximately 40%. Limulus anti-LPS factor (LALF) is a naturally occurring horseshoe crab derived protein that, unlike antibiotics, is both bactericidal for gram-negative bacteria and capable of neutralizing LPS. We hypothesized that a peptide derived from the active domain of LALF (LALF #28-54) would exhibit potent biologic activity similar to that of LALF itself and could potentially be useful as a therapeutic agent. METHODS: The effects of LALF, synthetic peptide LALF #28-54, polymyxin B (PmB), and a biologically inactive synthetic peptide were examined in several models. In vitro bactericidal activity was determined against Pseudomonas aeruginosa, and LPS-neutralizing capacity was determined via inhibition of LPS-induced tumor necrosis factor-alpha (TNF-alpha) secretion by RAW 264.7 cells. In vivo biologic activity was determined via pretreatment following which P aeruginosa endotoxemia or bacteremia was induced; serum TNF-alpha levels, bacterial clearance, and survival were assessed. RESULTS: LALF and LALF #28-54 exhibited potent in vitro bactericidal and LPS-neutralizing activity comparable to PmB (P <.01). However, although LALF #28-54 diminished systemic TNF-alpha production and aided bacterial clearance similar to that observed for LALF (P <.01), it did not provide significant protective capacity (P >.1). CONCLUSIONS: These data demonstrate that peptide LALF #28-54 retained the LPS-neutralizing and bactericidal biologic activity of LALF but failed to protect during overwhelming P aeruginosa bacteremia, perhaps due to short serum half-life.

Low estimates of HIV seroconversions among clients of a drug treatment clinic in San Francisco, 1995 to 1998.

We estimated HIV incidence among injection drug users attending a drug treatment clinic in San Francisco from 1995 to 1998 using two methods. An anonymous sequential testing method identified no seroconversions among clients seen more than once during the period (one-sided upper 95% confidence limit 1.02 per 100 person-years). A sensitive/less sensitive immunoassay testing strategy detected no early infections (one-sided upper 95% confidence limit 1.90% per year). Methods were concordant and feasible in the setting. Although detection of no new HIV infections in this population of injection drug users (IDUs) is encouraging, epidemiologic studies among IDUs not in treatment are needed to monitor the HIV epidemic effectively.

Home collection versus publicly funded HIV testing in San Francisco: who tests where?

We examined records of all HIV antibody tests performed at anonymous publicly funded (PF) sites and by home collection (HC) testing for residents of San Francisco from August 1996 to December 1997. Although far fewer tests were performed by HC testing than at PF sites (715 versus 8712, respectively), a higher proportion of HC testers reported no prior history of HIV testing (33.1% versus 17.9%). HIV seroprevalence was higher among PF tests (1.8%) than among HC tests (0.9%). Compared with PF testers, HC testers were less likely to be gay men, lesbian or bisexual women, heterosexual women, African American, or Latino. HC testers were more likely to report sex with a known HIV-positive partner. HC testers were also more likely to reside in affluent neighborhoods. HC testing reaches some high-risk persons who may not otherwise seek PF testing, although, overall, the risk profile of HC testers appeared lower than that of PF testers. HC testing reaches some individuals who can financially afford HC testing, thus saving public prevention resources for hard-to-reach, high-risk populations.

Antiendotoxin agents share molecular homology within their lipopolysaccharide binding domains.

BACKGROUND: The purpose of this study was to determine whether antiendotoxin agents exhibit molecular homology within their lipopolysaccharide (LPS) binding domains, suggesting a common mechanism of action. We hypothesized that the presence of positively charged basic amino acids or a paucity of negatively charged acidic amino acids, or both, would be a critical characteristic of that portion of the molecule that binds to the highly negatively charged deep core/lipid A (DCLA) region of LPS. MATERIALS AND METHODS: We analyzed the amino acid sequences of the variable light (VL) and heavy (VH) chain complementarity-determining regions (CDRs) of anti-DCLA monoclonal antibodies (mAbs) 1B6, 5A5, and 7C5 and compared them with (1) the CDRs of three irrelevant control mAbs and (2) the LPS binding region of bactericidal permeability-increasing protein (BPI). We purified and amplified the specific nucleotide sequences of the variable regions using reverse transcriptase polymerase chain reaction. DNA was sequenced by dideoxy termination, and protein sequences were deduced and analyzed. The percentages of acidic, basic, polar, and hydrophobic amino acids within VH and VL chain CDRs were determined. RESULTS: We identified a paucity of negatively charged acidic amino acids exclusively within VL chain CDRs of anti-DCLA mAbs (P < 0.005). Although increased, the number of positively charged basic residues was not statistically significantly different; neither was the number of polar or hydrophobic amino acids. Conclusions. Our data suggest that the near absence of negatively charged acidic residues is critical for LPS binding. This characteristic appears to reside exclusively in the VL chain CDRs of anti-DCLA mAbs.

Detection of early HIV infection and estimation of incidence using a sensitive/less-sensitive enzyme immunoassay testing strategy at anonymous counseling and testing sites in San Francisco.

Timely estimates of HIV incidence are needed to monitor the epidemic and target primary prevention but have been difficult to obtain. We applied a sensitive/ less-sensitive (S/LS) enzyme immunoassay (EIA) testing strategy to stored HIV-positive sera (N = 452) to identify early infections, estimate incidence, and characterize correlates of recent seroconversion among persons seeking anonymous HIV testing in San Francisco from 1996 to 1998 (N = 21,292). Sera positive on a sensitive EIA but negative on a less-sensitive EIA were classified as early HIV infections; sera positive on both EIA were classified as long standing. Seventy-nine sera were from people with early HIV infection. Estimated HIV incidence was 1.1% per year (95% confidence interval [CI], 0.68%-1.6%) overall and 1.9% per year (95% CI, 1.2%-3.0%) among men who have sex with men (MSM). Early HIV infection among MSM was associated with injection drug use, unprotected receptive anal sex, and multiple sex partners in the previous year. No temporal trend in HIV incidence was noted over the study period. The S/LS strategy provides a practical public health tool to identify early HIV infection and estimate HIV incidence in a variety of study designs and settings.

Estimation of human immunodeficiency virus (HIV) seroincidence among repeat anonymous testers in San Francisco.

The authors approximated human immunodeficiency virus (HIV) seroincidence in a population of men who have sex with men and who sought repeated anonymous HIV testing in San Francisco in 1995. The number of seroconversions and person-years of observation were estimated using the date and result of the current test and the self-reported date and result of the previous test. Estimates for HIV seroincidence (2.8 per 100 person-years, 95% confidence interval 2.3-3.4) and predictors of seroconversion were similar to those estimated from a prospective study of men who have sex with men conducted in San Francisco at the same time. While the limitations of self-reported data in a self-selected population are recognized, data from repeat testers may provide a practical surveillance tool.

HIV seroprevalence and risk behaviors among lesbians and bisexual women in San Francisco and Berkeley, California.

Few data are available on human immunodeficiency virus (HIV) infection and risk behaviors among lesbians and bisexual women. A total of 498 lesbians and bisexual women was sampled from public venues in San Francisco and Berkeley, Calif, during 1993. The overall HIV seroprevalence was 1.2%. Ten percent of participants reported injecting drugs since 1978. Forty percent of the participants reported unprotected vaginal or anal sex with men during the past 3 years, including unprotected sex with gay and bisexual men and male injection drug users. The high rates of injection drug use and unsafe sexual behaviors suggest that lesbians and bisexual women frequenting public venues in San Francisco and Berkeley are at risk for HIV infection.

Temporal trends in human immunodeficiency virus seroprevalence and sexual behavior at the San Francisco municipal sexually transmitted disease clinic, 1989-1992.

The authors analyzed temporal trends in human immunodeficiency virus (HIV) infection among men and women who visited the San Francisco municipal sexually transmitted disease clinic between 1989 and 1992, using blinded HIV seroprevalence data. Temporal changes in sexual behavior were evaluated by abstracting self-reported information on sexual behaviors from a random sample of charts of men who visited the clinic between 1990 and 1992. From 1989 to 1992, HIV seropositivity declined from 2.0% to 1.0% among women (p = 0.06) and from 18.9% to 12.0% (p < 0.001) among men. The percentage of patients who reported having anal intercourse in the previous year did not change significantly during the study period. The percentage of male patients who reported having vaginal intercourse during the previous year decreased from 82.9% to 78.6% (p < 0.05), and the percentage of male patients who reported engaging in receptive oral sex during the previous year increased from 24.0% to 41.6% (p < 0.001). The percentage of male patients who reported that they always used condoms increased from 31.8% to 49.2% for anal sex, from 8.7% to 19.5% for vaginal sex, and from 1.4% to 6.3% for oral sex (p < 0.05). Among patients visiting the sexually transmitted disease clinic, there was a steady and significant decline in HIV seroprevalence. The decline in HIV seroprevalence was accompanied by a significant trend toward safer sexual practices. However, by the end of the study period, less than half of the patients reported using condoms all of the time, which suggests that there is a need to expand behavioral interventions to focus on high-risk persons.

Anti-lipopolysaccharide monoclonal antibodies inhibit macrophage TNF messenger RNA synthesis in vitro.

Gram-negative bacterial lipopolysaccharide (LPS, endotoxin) directly stimulates macrophages to produce tumor necrosis factor (TNF). TNF, in turn, produces a constellation of adverse effects that includes hypotension, systemic acidosis, arterial hypoxemia, and death. Transcription of the TNF gene occurs within minutes of LPS stimulation and appears to be a critical control point in the synthesis and secretion of TNF protein by macrophages. We hypothesized that murine monoclonal antibody (mAb) 8G9 directed against Escherichia coli 0111:B4 LPS would provide protective capacity against an E. coli 0111:B4 bacterial challenge in vivo and would concurrently inhibit LPS-induced synthesis of TNF mRNA and secretion of TNF protein in vitro. E. coli 0111:B4 LPS was used to stimulate a macrophage-derived cell line (RAW 264.7) to produce TNF in the presence or absence of mAb 8G9. Media alone and LPS without 8G9 mAb served as controls against which the effect of 8G9 mAb was compared. Total cellular RNA was purified and analyzed by a Northern blotting technique utilizing a radiolabeled cDNA probe specific for TNF mRNA. TNF mRNA levels from each sample were quantitated by autoradiograph densitometry. Pretreatment with mAb 8G9 provided protective capacity against an intraperitoneal E. coli 0111:B4 bacterial challenge in vivo when compared with saline pretreatment alone (22% versus 90% mortality respectively, P < 0.05). Preincubation of LPS with mAb 8G9 resulted in a significant inhibition of LPS-induced TNF mRNA synthesis (63 +/- 20%, P < 0.01) and TNF protein secretion (88 +/- 10%, P < 0.001) in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of voluntary and blinded human immunodeficiency virus type 1 (HIV-1) seroprevalence surveys in a high prevalence sexually transmitted disease clinic population.

To compare the seroprevalence of and risk factors for human immunodeficiency virus infection (HIV) among patients attending a public sexually transmitted disease clinic, the authors conducted both voluntary and blinded seroprevalence surveys between June 1989 and August 1990. For the voluntary survey, every twenty-fifth patient attending the clinic for a new problem was invited to receive anonymous testing for HIV antibody. For the blinded survey, sera obtained for syphilis serologies from 2,297 (86%) of the 2,682 patients attending the clinic for a new problem were tested for HIV antibody after all personal identifiers were removed. Of the 946 eligible patients, 631 (66.7%) agreed to participate in the voluntary survey. Black men were significantly less likely to participate than other men and women (p < 0.0001). The prevalence of HIV antibody was 25% greater in the blinded survey than in the voluntary survey (15.2% and 11.4%, respectively, p < 0.05). This difference was due primarily to black homosexual/bisexual men, who had a 12.7-fold greater risk of HIV infection in the blinded survey than in the voluntary survey. These results suggest that blinded seroprevalence surveys may provide a better prevalence estimate of HIV infection than voluntary surveys. The greater risk for HIV infection observed among homosexual and bisexual black men, who were tested only in the blinded serosurvey, suggests that efforts to increase voluntary testing for HIV infection in this group should be developed.