Charles C. J. Carpenter

Effects of Prostaglandins, Theophylline, and Cholera Exotoxin Upon Transmucosal Water and Electrolyte Movement in the Canine Jejunum

A canine model was utilized to study and compare the effects of prostaglandins E1, A1, and F2α, theophylline, and cholera exotoxin upon net absorption or secretion of water and electrolytes from the jejunum. Superior mesenteric artery infusions of prostaglandins E1, A1, and F2α, and of theophylline each induced net secretion of water and electrolytes from the jejunum. Prostaglandin infusion into the jejunal lumen had a lesser effect upon net fluid movement than did prostaglandin infusion into the superior mesenteric artery at the same rates. Mucosal application of cholera exotoxin induced net secretion rates which exceeded the maximum net secretory rates induced by prostaglandin infusions. When theophylline and prostaglandin F2α were simultaneously infused into the superior mesenteric artery at low rates, significant synergism in the effect of these two agents on fluid movement was observed. There was a significant correlation between the magnitude of effect of intra-arterial prostaglandin and of intraluminal cholera exotoxin when determined in the same dog. The possible mechanisms by which these agents alter jejunal fluid movement are discussed and the possibility that they may act upon a single secretory mechanism is considered.

Hierarchical pattern of mucosal candida infections in HIV-seropositive women

PURPOSE Candida is the most common cause of opportunistic mucosal infections in human immunodeficiency virus (HIV)-positive women. We had observed an apparent correlation between the severity of immunodeficiency and the site of mucosal candida infection. The current study was designed to determine whether significant correlations existed between the sites of mucosal candida infection and the degree of immunodeficiency, as determined by subsets of lymphocyte populations. PATIENTS AND METHODS The subjects in this study are 66 HIV-seropositive women evaluated by members of the Brown University Acquired Immunodeficiency Syndrome (AIDS) Program during the 3-year period, September 1, 1986, through August 30, 1989. All patients had thorough clinical evaluations and relevant laboratory studies at defined intervals. All patients with CD4 lymphocyte counts below 0.2 X 10(9)/L received zidovudine therapy as soon as it became available. After July 1988, all patients with CD4 counts below 0.2 X 10(9)/L received prophylaxis against Pneumocystis carinii pneumonia. All patients were counseled about HIV infection, its modes of transmission, and the early symptoms of opportunistic infections. RESULTS The longitudinal data demonstrated that candida often infected vaginal mucosa when there was no significant reduction in CD4 lymphocyte counts. Candida infection of the oropharyngeal mucosa was associated with highly significant reductions in CD4 lymphocyte counts. Esophageal candidiasis occurred only with advanced immunodeficiency associated with CD4 counts below 0.1 X 10(9)/L. CONCLUSIONS Candida mucosal infections occur in a hierarchical pattern in women with HIV infection. Determination of the basis for the differences in susceptibility to candida of the vaginal, oropharyngeal, and esophageal mucosal surfaces will require further studies.

THE ROLE OF THE RENIN-ANGIOTENSIN SYSTEM IN THE CONTROL OF ALDOSTERONE SECRETION

Within the last year, evidence (1-4) has accumulated to show that the kidney secretes a hormone which is a prime regulator of aldosterone secretion. The renal origin of an aldosteronestimulating hormone (ASH) has been demonstrated following acute blood loss (1-3), during chronic thoracic caval constriction (4), and during chronic Na depletion (4). Nephrectomizedhypophysectomized dogs failed to respond to acute hemorrhage with an increase in aldosterone secretion, and acute bilateral nephrectomy of hypophysectomized caval and hypophysectomized Nadepleted dogs resulted in a marked drop in aldosterone secretion. Furthermore, crude saline extracts of kidney produced a striking increase in aldosterone secretion (1-5). In malignant experimental renal hypertension, hyperaldosteronism was consistently present (6). These findings and the reports that renin preparations (6) and synthetic angiotensin II (6-8) increase the rate of aldosterone production suggest the possibility that ASH is renin. The present experiments were undertaken to determine the chemical nature of this ASH by fractionation of crude kidney extracts for aldosterone-stimulating and pressor activity. The renin content of kidneys from dogs with thoracic caval constriction and secondary hyperaldosteronism and from normal dogs has been compared. Since dogs with thoracic caval constriction and Na-depleted dogs do not have hypertension, the response in blood pressure to synthetic angiotensin

Effect of highly active antiretroviral therapy on cervicovaginal HIV-1 RNA.

ObjectivesTo determine the frequency of cervicovaginal lavage and plasma HIV-1 RNA levels that are below detectable levels (< 400 copies/ml) among women on highly active antiretroviral therapy (HAART), non-HAART and on no therapy. To compare the effect of initiating HAART on the timing of HIV-1 RNA suppression in the blood plasma and genital tract among antiretroviral-naïve women. MethodsData were obtained from 205 HIV-infected women with paired plasma and cervicovaginal lavage viral load measurements. Seven antiretroviral-naïve women starting HAART had viral load measurements performed daily for one week, at 2 weeks and at 1 month after initiating therapy. Viral load quantification was carried out by nucleic acid sequence-based amplification assay. The lower limit of detection was 400 copies/ml. ResultsPlasma and cervicovaginal HIV-1 RNA was detectable in 71 and 26% of the women, respectively. Among women with plasma viral loads less than 400, 400–9999, and 10 000 copies/ml or over, genital tract HIV-1 RNA was detected in 3, 17 and 48%, respectively (P < 0.001). Fifty-one per cent of the women with CD4 cell counts of less than 200/mm3 had detectable cervicovaginal viral loads compared with 18% among women with CD4 cell counts of 200/mm3 or over (P < 0.001). Cervicovaginal HIV-1 RNA was less than 400 copies/ml in 85% of those on HAART, 69% of those on non-HAART and 69% of those on no therapy (P < 0.045). In seven antiretroviral-naïve women initiating HAART, cervicovaginal HIV-1 RNA decreased by 0.7–2.1 log10 within 1–14 days of starting therapy. ConclusionThe cervicovaginal HIV-1 RNA level was positively correlated with plasma HIV-1 RNA and negatively with the CD4 cell count. The use of HAART was significantly associated with below-detectable levels of HIV-1 RNA in both plasma and the genital tract. HIV-1 RNA suppression in the genital tract may occur rapidly after initiating therapy.

Association between bacterial vaginosis and expression of human immunodeficiency virus type 1 RNA in the female genital tract.

We assessed the effect of lower genital tract infections on human immunodeficiency virus type 1 (HIV-1) RNA shedding in the female genital tract. Bacterial vaginosis was significantly associated with HIV-1 RNA expression in the female genital tract of HIV-infected women.

Site and characteristics of electrolyte loss and effect of intraluminal glucose in experimental canine cholera

The site and characteristics of gastrointestinal electrolyte loss were investigated in eight dogs with experimental cholera induced by orogastric administration of 6-hr broth cultures of Vibrio cholerae, strain Ogawa 395. In these animals, all electrolyte losses originated in the small bowel, predominantly from the jejunum and ileum. The bicarbonate concentration of the small bowel fluid showed a progressive increase from duodenum, where it was less than that of plasma, to the terminal ileum, where it was significantly greater than that of simultaneously obtained plasma. Studies of the responses of chronic Thiry-Vella jejunal loops (five dogs) and chronic Thiry-Vella ileal loops (five dogs) to intraluminal challenge by cholera exotoxin demonstrated that all loops exhibited isotonic electrolyte loss for a 14-18 hr period after challenge. The bicarbonate concentration of fluid produced by exotoxin-challenged jejunal loops was not significantly different from that of plasma, whereas the ileal loops produced fluid with a bicarbonate concentration approximately three times that of plasma. The effect of intraluminal glucose on the response of canine gut to cholera exotoxin was investigated by perfusion studies in 12 dogs with chronic Thiry-Vella fistulae. Intraluminal glucose significantly enhanced isotonic fluid absorption in both jejunal and ileal loops. The net effects of glucose on isotonic fluid absorption were equal before and after intraluminal administration of crude cholera exotoxin. These data suggest that cholera exotoxin causes gut electrolyte loss by a mechanism independent of that by which glucose enhances sodium absorption.

Development of proteinuria or elevated serum creatinine and mortality in HIV-infected women.

BackgroundData on the incidence and prognostic significance of renal dysfunction in HIV disease are limited. ObjectiveTo determine the incidence of proteinuria and elevated serum creatinine in HIV-positive and HIV-negative women and to determine whether these abnormalities are predictors of mortality or associated with causes of death listed on the death certificate in HIV-positive women. DesignThe incidence of proteinuria or elevated serum creatinine and mortality was assessed in a cohort of 885 HIV-positive women and 425 at-risk HIV-negative women. SettingWomen from the general community or HIV care clinics in four urban locations in the United States. Outcome MeasuresCreatinine of ≥1.4 mg/dL, proteinuria 2+ or more, or both. Deaths confirmed by a death certificate (92%) or medical record/community report (8%). ResultsAt baseline, 64 (7.2%) HIV-positive women and 10 (2.4%) HIV-negative women had proteinuria or elevated creatinine. An additional 128 (14%) HIV-positive women and 18 (4%) HIV-negative women developed these abnormalities over the next (mean) 21 months. Relative hazards of mortality were significantly increased (adjusted relative hazard = 2.5; 95% confidence interval: 1.9–3.3), and there were more renal causes recorded on death certificates (24/92 (26%) vs. 3/127 (2.7%), p < .0001) in HIV-infected women with, compared with those without these renal abnormalities. ConclusionsProteinuria, elevated serum creatinine, or both frequently occurred in these HIV-infected women. These renal abnormalities in HIV-infected women are associated with an increased risk of death after controlling for other risk factors and with an increased likelihood of having renal causes listed on the death certificate. The recognition and management of proteinuria and elevated serum creatinine should be a priority for HIV-infected persons.

Differences in access to zidovudine (AZT) among symptomatic HIV-infected persons

Object:To evaluate socioeconomic factors that determine whether symptomatic HIV-infected persons are offered zidovudine (AZT).Design:Cross-sectional survey conducted as part of the Robert Wood Johnson Foundation’s AIDS Health Services Program.Setting:Public hospital clinics and community-based AIDS organizations in nine American cities.Patients:880 HIV-seropositive outpatients interviewed between October 1988 and May 1989.Main results:Males were more likely to have been offered AZT than were females (adjusted odds ratio 2.99; 95% confidence interval 1.67 to 5.36), those with insurance were more likely to have been offered AZT than were those without (adjusted odds ratio 2.00; 95% confidence interval 1.25 to 3.21), and whites more likely to have been offered AZT than were non-whites (adjusted odds ratio 1.73; 95% confidence interval 1.11 to 2.69). Intravenous drug users were less likely to have been offered AZT than were non-drug users (adjusted odds ratio 0.44; 95% confidence interval 0.28 to 0.69). Persons who had had an episode of Pneumocystis cariniipneumonia were more likely to have been offered AZT than were persons who had AIDS and had not had Pneumocystis cariniipneumonia (adjusted odds ratio 2.95; 95% confidence interval 1.71 to 5.11).Conclusion:The authors conclude that traditionally dis-advantaged groups have less access to AZT, the only antiretroviral agent demonstrated to increase survival of patients who have symptomatic HIV infection.

Human immunodeficiency virus infection in North American women: experience with 200 cases and a review of the literature.

This study was designed to define the epidemiology and natural history of human immunodeficiency virus (HIV) infection in women in Rhode Island. Two hundred women referred to Brown University physicians from 1986 through 1990 were evaluated at 3-to-6-month intervals for 12 to 60 months. All received antiretroviral therapy and prophylaxis against opportunistic infections when indicated on the basis of CD4 lymphocyte counts. Major findings included: 1) rapid shift of dominant mode of transmission from intravenous drug sharing to heterosexual route; 2) significant gender-specific differences in clinical presentation; 3) increased frequency of cervical dysplasia in women infected via intravenous needle sharing; 4) no definite gender-specific differences in progression of HIV infection; 5) enormous societal impact of HIV infection in women. Principal conclusions are: 1) rapid change to predominantly heterosexual HIV transmission can occur in North America, with serious societal impact; 2) gender-specific clinical features can lead to earlier diagnosis of HIV infection in women; 3) HIV infection in women does not pursue an inherently more rapid course than that observed in men.

Misdiagnosis of HIV infection by HIV-1 plasma viral load testing: a case series.

The current standard of care for patients infected with HIV includes plasma viral load tests to monitor the effectiveness of antiretroviral regimens (1, 2). The assays approved for this use detect cell-free plasma viral RNA by using various amplification techniques (2). Access to these sensitive techniques and the trend toward earlier and more aggressive treatment approaches have led to the use of these assays as primary tools for the diagnosis of acute HIV infection (3, 4). Plasma viral load tests for HIV-1 were neither developed nor evaluated for the diagnosis of HIV infection; therefore, their diagnostic specificity is not well delineated when applied to persons who are negative for HIV antibody (5). We report two cases of false-positive results obtained by using branched-chain DNA assay (Chiron Quantiplex, Emeryville, California) and one case of a false-positive result obtained by using HIV reverse transcriptase polymerase chain reaction (RT-PCR) (Roche Amplicor Monitor, Basel, Switzerland) plasma viral load assay. These three cases demonstrate the potential problems of using HIV-1 plasma viral load tests for diagnosis of HIV infection. Case One A previously healthy 12-year-old boy, whose HIV-infected mother is cared for at one of our institutions, presented for evaluation of a positive plasma viral load of 1254 copies/mL determined by using the branched-chain DNA assay (Chiron Quantiplex) for HIV-1 RNA. The patients mother had received a diagnosis of HIV infection around the time of his birth, and the patient had tested negative for HIV-1 by enzyme-linked immunosorbent assay (ELISA) several times in the years after his birth. Although the patient reported no risk factors for HIV infection, he underwent plasma viral load testing after his primary care physician noted a skin lesion that was interpreted as herpes zoster. At our institution, the patient subsequently had a negative result on HIV-1 ELISA, a normal CD4 cell count and CD4:CD8 ratio, and a negative plasma viral load (also determined by using the branched-chain DNA assay). His skin lesion was diagnosed as impetigo, and he remains in excellent health 3 months after his initial presentation. Case Two A previously healthy, pregnant 40-year-old woman presented for an HIV test. Her male sexual partner, with whom she had recently had repeated unprotected vaginal intercourse, had been given a diagnosis of HIV infection 1 week before her office visit. The patient tested negative for HIV-1 antibody on the oral mucosal transudate (OraSure, Epitope, Inc., Beaverton, Oregon) HIV-1 oral specimen collection device but continued to be concerned about her HIV status. One week after her initial presentation, she underwent a plasma viral load test (Chiron Quantiplex) for HIV-1 RNA that yielded a positive value of 1574 copies/mL. The patient was told that she was probably infected with HIV. During the next 3 months, she had a negative result on an HIV-1 ELISA, a normal CD4 cell count and CD4:CD8 ratio, and three HIV-1 plasma viral load tests (all done by using branched-chain DNA assay) that showed an undetectable viral load. When the patient delivered a healthy baby 7 months after her initial presentation, another HIV-1 ELISA yielded negative results. Case Three A 20-year-old healthy woman was referred for further evaluation by her primary care physician when she had a positive result on HIV-1 ELISA and an indeterminate result on a Western blot test. The patients only risk factor was heterosexual intercourse, but she stated that her partner had used condoms consistently during the previous year. During a 4-month period after her indeterminate result on the Western blot test, she had a positive result on ELISA and an indeterminate result on a Western blot test on separate occasions. Five months later, both ELISA and a Western blot test yielded negative results, but the patient had a plasma viral load of 1300 copies/mL (determined by using RT-PCR assay [Roche Amplicor Monitor]). She was subsequently counseled that she was probably infected with HIV. Nearly 6 months after her initial indeterminate HIV test result, she was tested by a third laboratory and was negative for HIV-1 antibodies on both ELISA and Western blot test. She had a normal CD4 cell count and CD4:CD8 ratio and a plasma viral load that was undetectable on RT-PCR assay (Roche Amplicor Monitor). She remains healthy 8 months after her initial presentation. Discussion These three cases, which were observed in one region during a 2-month period, are probably examples of false-positive results on HIV-1 plasma viral load tests. Only one other case of a false-positive HIV-1 plasma viral load has been fully documented; that test had been performed by using RT-PCR, and the result was thought to be related to the administration of an HIV-1 vaccine (6). The patients described here had normal CD4 cell counts and CD4:CD8 ratios, low plasma viral loads, and subsequent negative results on HIV-1 ELISA and plasma viral load tests. To our knowledge, the lowest reported plasma viral load during seroconversion is more than 17 times higher than the highest viral load detected in our three patients (7). Although transient HIV infection has been reported in infants, it is unlikely in two of our patients because they had not recently been exposed to HIV (8, 9). Other potential explanations of false-positive HIV-1 plasma viral load include laboratory error, cross-contamination, and mix-up of specimens. From the patients perspective, false-positive results on an HIV test are potentially devastating, regardless of the cause. Further clinical experience is required to determine whether specific clinical circumstances correlate with an increased incidence of false-positive HIV-1 plasma viral load results. The current standard diagnostic protocol for HIV infection is based on detection of HIV-1-specific antibodies. The combination of screening ELISA followed by a confirmatory Western blot assay has been more than 99% accurate in detecting HIV infection (10, 11). This protocol has a relatively low rate of false-positive results (approximately 0.0006%) but can have negative or indeterminate results during the 3 to 4 weeks before seroconversion (12-14). Although host antibody responses may be undetectable during this acute infection period, the viral load in plasma is usually very high and initial viremia usually occurs in 4 to 11 days (4, 7, 15, 16). The occurrence of high levels of viremia during primary HIV infection has led some physicians to use plasma viral load assays as diagnostic tests to detect early HIV infection. However, plasma viral load assays are designed for monitoring the effectiveness of antiretroviral therapies and for measuring the quantity of virus in patients with confirmed HIV infection, not for the diagnosis of HIV infection. Their performance in patients who are not infected with HIV is unknown (1, 2). The first case illustrates the importance of following the most recent testing protocol for the diagnosis of HIV infection. The patients pediatrician requested a plasma viral load assay because the patient, whose mother has asymptomatic HIV infection, presented with a skin rash thought to be consistent with herpes zoster. In this case, because primary HIV infection was not suspected, an HIV-1 ELISA should have been ordered and, if reactive, followed by a Western blot assay. In the second case, a plasma viral load assay was ordered despite a negative result on an oral mucosal transudate test (OraSure) because the patient was pregnant and was at substantial risk for recent exposure to HIV. However, on the basis of current knowledge about viral replication during primary HIV infection, the patients plasma viral load would probably have been much higher if she had been infected with HIV in the previous 2 weeks (15). In the third case and in other cases described in the literature, plasma viral load testing was used to further analyze an indeterminate result on an HIV-1 Western blot assay (3). To minimize the occurrence of false-positive results, testing protocols for the diagnosis of HIV infection should include tests that complement each other. The HIV-1 ELISA assay, which has excellent diagnostic sensitivity, remains an important, inexpensive screening tool. Because of its high specificity, the HIV-1 Western blot assay is a reliable confirmatory test after reactive ELISA. Only patients who have a high pretest probability of a positive result should be evaluated for primary HIV infection by using plasma viral load testing. Such patients include those who are at high risk for recent exposure to HIV and present with indeterminate or negative results on Western blot tests and especially those with an appropriate accompanying clinical syndrome (4). A patient with a high HIV-1 plasma viral load is most likely in the process of seroconversion; although it is theoretically possible that a patient with an undetectable or low plasma viral load may have recently been infected with HIV, that possibility is much less likely. It is important to consider the pretest likelihood of acute infection when counseling patients with negative results on serologic testing and a low plasma viral load. Physicians should explain that the patient may not be infected with HIV-1 but should take precautions to avoid infecting others until follow-up testing provides a definite result. If HIV-1 plasma viral load testing is used in the diagnosis of primary HIV infection before the development of serum antibodies, low positive plasma viral load results should be interpreted with caution and the patients true disease status should be confirmed with repeated plasma viral load testing and follow-up serologic testing.