Effects of CD4 and CD8 T lymphocyte depletion on the course of histoplasmosis following pulmonary challenge

Use of a pulmonary model of histoplasmosis in CD4/CD8 lymphocyte depleted animals offers an opportunity to study pathogenesis in a setting resembling AIDS. Flow cytometric analysis demonstrated that administration of anti-CD4 and anti-CD8 antibodies reduced CD4 and CD8 T cell subsets in the lungs, lymph nodes and spleen. Depletion of these cells transformed the infection from a self-limited course in normal mice to a progressive, fatal course in CD4/CD8 depleted mice. CD4 depletion alone had a lesser effect on survival, but increased fungal burden, while CD4/CD8 depletion had the greatest effect. Histopathologic studies showed marked differences in the inflammatory response between the dually depleted animals and the non-depleted controls. In conclusion, the course of histoplasmosis in CD4/CD8 depleted animals is progressive and fatal, resembling that observed in immunosuppressed patients. This model appears suitable for investigation of immunity to H. capsulatum, and should be useful for evaluation of treatment in the immunocompromised host.

Effect of CD40 ligand on the course of murine histoplasmosis

CD40 ligand-CD40 ligation is important in the development of T-cell-mediated immune responses. The purpose of this study was to examine the role of CD40L in recovery from histoplasmosis using a murine model of intratracheally induced infection. B6C3F1 mice were infected intratracheally with Histoplasma capsulatum yeast and monitored for clearance of the organism from the lungs and spleen. CD40L treatment was begun on either day -2 or +2 post inoculation and continued until day 14 in CD4-depleted animals and from day -2 to day +4 in non-immunosuppressed animals. Amphotericin B treatment was begun four days following inoculation and given every other day for 10 days. CD40L reduced fungal burden by less than one log when started two days before infection but did not act synergistically with low-dosage amphotericin B (0.2 mg kg(-1) qod) in CD4 depleted mice. Low-dose amphotericin B, CD40L, and the combination of the two failed to lower the fungal burden in a second experiment using a more virulent isolate of the same strain of H. capsulatum in CD4-depleted mice. Furthermore, CD40L did not increase the concentrations of IFN-gamma, IL-12 or IL-10 in the lungs or spleens of infected animals. In summary, CD40L had minimal or no effect on the course of infection in this murine model of histoplasmosis.

Emergence of resistance to fluconazole as a cause of failure during treatment of histoplasmosis in patients with acquired immunodeficiency disease syndrome

In sequential clinical trials of treatment for histoplasmosis in patients with acquired immunodeficiency syndrome, therapy with fluconazole failed in a higher proportion of patients than did therapy with itraconazole. To determine the cause for failure with fluconazole, antifungal susceptibility testing that used modified National Committee on Clinical Laboratory Standards procedures was performed on all baseline and failure isolates. Failure occurred more frequently in patients with baseline isolates with fluconazole minimum inhibitory concentrations (MICs) > or =5 microg/mL versus lower MICs; 29% versus 3%, respectively. There was at least a 4-fold increase in fluconazole MIC in the isolates from 10 (59%) of 17 patients for whom paired pretreatment and failure or relapse isolates were available. Cross-resistance to itraconazole was not seen. In conclusion, fluconazole is less active than itraconazole for Histoplasma capsulatum and induces resistance during therapy, which accounted for treatment failure in some patients.

Effect of tension-free vaginal tape procedure on urodynamic continence indices

OBJECTIVE

To assess the difference in measured urethral function before and after tension-free vaginal tape procedure (TVT).

METHODS

Women who underwent TVT for genuine stress incontinence with or without intrinsic sphincter deficiency completed this study. Multichannel urodynamic testing was performed preoperatively and 6 weeks postoperatively. Maximum urethral closure pressure and pressure transmission ratio were recorded. Valsalva leak point pressures were determined at 150 mL and at full bladder capacity. Resting and straining urethral angles were measured using the cotton swab technique. Subjects completed both the Incontinence Impact Questionnaire and Urodynamic Distress Inventory preoperatively and postoperatively.

RESULTS

Thirty-five consecutive women were studied. Twenty-three (65.7%) had a preoperative diagnosis of intrinsic sphincter deficiency as defined by maximum urethral closure pressure less than 20 cm H(2)O and/or Valsalva leak point pressure less than 60 cm H(2)O. Subjective and objective success rates were 91% and 83%, respectively. Subjects showed an 86.8% (95% CI 71.9%, 100.0%) improvement in their Incontinence Impact Questionnaire score and a 72.9% (95% CI 62.6%, 83.1%) improvement in their Urodynamic Distress Inventory score. The mean change in maximum urethral closure pressure was -1.3 cm H(2)O (95% CI -5.9, 3.3), whereas the pressure transmission ratio increased 15.7% (95% CI 5.0%, 26.3%). The mean decrease in straining urethral angle was 16.3 degrees (95% CI -23.9 degrees, -8.7 degrees ). Cured subjects demonstrating hypermobility preoperatively continued to do so postoperatively.

CONCLUSION

There was a significant increase in pressure transmission ratio, but not maximum urethral closure pressure, after TVT. These changes are similar to those reported after retropubic urethropexy and traditional sling procedures. The effectiveness of the TVT sling does not appear to depend on a clinically significant change in the straining urethral angle.

Subsequent sexually transmitted infection in urban adolescents and young adults

OBJECTIVE

To compare the rates of subsequent infection with Chlamydia trachomatis, Neisseria gonorrhoeae, or Trichomonas vaginalis in a group of high-risk adolescents and young adults.

METHODS

At the time of treatment, 444 unmarried teenagers and young adults aged 13 to 25 years were enrolled from an urban sexually transmitted disease clinic and 3 community-based primary care clinics. Subjects were infected with C trachomatis, N gonorrhoeae, or T vaginalis, were diagnosed as having nongonococcal urethritis (in men), or were uninfected sexual contacts with one of these infections. Subjects returned at 1, 3, 5, and 7 months.

RESULTS

The rate of subsequent infection was substantial. Forty percent of men and 53% of women who were uninfected contacts at enrollment were estimated to be infected within 7 months; 60% of men and 73% of women infected at enrollment were estimated to be reinfected. Among women, subjects who were infected at enrollment had a shorter time to subsequent infection (median, 140 days) compared with uninfected contacts (median, 209 days) (P =.04). Among men, findings were similar, but the difference in median time to subsequent infection was not significant (P =.08). Baseline characteristics that predicted shorter time to reinfection were female sex and infection at enrollment. When sexual behaviors in the 2 months preceding each subsequent data collection visit were included in the model, only being female and reporting at least one new interval sexual partner were significant predictors of subsequent sexually transmitted infections.

CONCLUSIONS

These data support recent research that has found high rates of subsequent infection among high-risk adolescents and young adults. Contacts of a sexually transmitted infection appear to be at equally high risk for subsequent infection as those with a personal history of infection. Our data suggest that more frequent than annual screening for N gonorrhoeae, C trachomatis, and T vaginalis would be appropriate in at-risk adolescent and young adult populations, including individuals who are uninfected sexual contacts to a sexually transmitted infection.

Effect of chronic fluoride exposure in uremic rats

This study was conducted to test the hypothesis that the margin of safe fluoride exposure is narrowed in rats that are physiologically compromised by renal dysfunction. The study objective was to determine whether increases in fluoride retention and tissue fluoride levels in rats with surgically induced renal insufficiency result in toxic fluoride effects not ordinarily observed in healthy animals. Uremic and sham-operated control rats received 0 microg/ml, 5 (0.26 mmol/l), 15 (0.79), or 50 microg/ml (2.63 mmol/l) of fluoride in their drinking water for 3 or 6 months. Fluoride retention was monitored, and, following euthanasia, tissue fluoride and biochemical markers of tissue function were analyzed. Selected tissues were saved for histology, and bone marrow cells were harvested for determining the frequency of sister chromatid exchange, a marker of genetic damage. In spite of significantly higher levels of fluoride in the tissues of the animals with renal insufficiency, there were no clinically adverse, fluoride-induced, extraskeletal physiological, biochemical, or genetic effects of chronic exposure to common levels of fluoride in these rats.

Comparison of a new triazole, posaconazole, with itraconazole and amphotericin B for treatment of histoplasmosis following pulmonary challenge in immunocompromised mice

A murine model of intratracheally induced histoplasmosis in immunocompromised B6C3F(1) mice was used to evaluate a new triazole antifungal agent, posaconazole. This compound was previously shown to be comparable to amphotericin B and superior to itraconazole for the treatment of histoplasmosis in immunocompetent mice. The current study used mice that were depleted of T lymphocytes by intraperitoneal injection of anti-CD4 and anti-CD8 monoclonal antibodies beginning 2 days before infection and continuing at 5-day intervals until completion of the study. Groups of B6C3F(1) mice that were depleted of CD4 and CD8 T cells were infected with an inoculum of 10(4) Histoplasma capsulatum yeasts. All mice receiving posaconazole at 1 or 0.1 mg/kg of body weight/day, amphotericin B at 2 mg/kg every other day (qod), or itraconazole at 75 mg/kg/day survived to day 29. Only 60% of mice receiving itraconazole at 10 mg/kg/day and none receiving amphotericin B at 0.2 mg/kg qod survived to that date. Fungal burdens were determined at day 14 of infection, 1 day after discontinuation of therapy. Quantitative colony counts and Histoplasma antigen levels in lung and spleen tissues declined following treatment with amphotericin B at 2 mg/kg qod, posaconazole at 5 and 1 mg/kg/day, and itraconazole at 75 mg/kg/day but not in mice treated with amphotericin B at 0.2 mg/kg qod or itraconazole at 10 mg/kg/day. Posaconazole at 0.1 mg/kg/day reduced fungal colony counts and antigen levels in spleens but not in lungs. This study shows posaconazole activity for the treatment of histoplasmosis in immunosuppressed animals.

Comparison of the echinocandin caspofungin with amphotericin B for treatment of histoplasmosis following pulmonary challenge in a murine model

Twenty clinical isolates of Histoplasma capsulatum were tested for their in vitro susceptibilities to caspofungin in comparison to those to amphotericin B by following National Committee for Clinical Laboratory Standards guidelines for yeasts. The mean MICs were 16.6 microgram/ml (range, 8 to 32 microgram/ml) for caspofungin and 0.56 microgram/ml (range, 0.5 to 1.0 microgram/ml) for amphotericin B. Survival experiments used a 10(5) dose in a pulmonary challenge model with B6C3F(1) mice. All mice that received amphotericin B at 2 mg/kg of body weight every other day (q.o.d.), 30% of mice that received caspofungin at 8 mg/kg/day, and 20% of mice that received caspofungin at 4 mg/kg/day survived to day 15, while mice that received caspofungin at 2 mg/kg/day and all control mice that received the vehicle died by day 14. Amphotericin B at 2 mg/kg q.o.d. markedly reduced the fungal burden in the lungs and spleens, as measured by Histoplasma antigen detection techniques and quantitative cultures, for each comparison. Caspofungin at 10 mg/kg twice a day (b.i.d.) did not reduce the fungal burden, as measured by antigen detection techniques, but slightly reduced the levels of fungi in both the lungs and spleens, as determined by quantitative cultures. Caspofungin at 5 mg/kg b.i.d. did not affect fungal burden. Overall, caspofungin had only a slight effect on survival or fungal burden.

Comparison of nikkomycin Z with amphotericin B and itraconazole for treatment of histoplasmosis in a murine model

Nikkomycin Z was tested both in vitro and in vivo for efficacy against Histoplasma capsulatum. Twenty clinical isolates were tested for susceptibility to nikkomycin Z in comparison to amphotericin B and itraconazole. The median MIC was 8 microg/ml with a range of 4 to 64 microg/ml for nikkomycin Z, 0.56 microg/ml with a range of 0.5 to 1.0 microg/ml for amphotericin B, and < or =0.019 microg/ml for itraconazole. Primary studies were carried out by using a clinical isolate of H. capsulatum for which the MIC of nikkomycin Z was greater than or equal to 64 microg/ml. In survival experiments, mice treated with amphotericin B at 2.0 mg/kg/dose every other day (QOD) itraconazole at 75 mg/kg/dose twice daily (BID), and nikkomycin Z at 100 mg/kg/dose BID survived to day 14, while 70% of mice receiving nikkomycin Z at 20 mg/kg/dose BID and none of the mice receiving nikkomycin Z at 5 mg/kg/dose BID survived to day 14. All vehicle control mice died by day 12. Fungal burden was assessed on survivors. Mice treated with nikkomycin Z at 20 and 100 mg/kg/dose BID had significantly higher CFUs per gram of organ weight in quantitative cultures and higher levels of Histoplasma antigen in lung and spleen homogenates than mice treated with amphotericin B at 2.0 mg/kg/dose QOD or itraconazole at 75 mg/kg/dose BID. Studies also were carried out with a clinical isolate for which the MIC of nikkomycin Z was 4 microg/ml. All mice treated with amphotericin B at 2.0 mg/kg/dose QOD; itraconazole at 75 mg/kg/dose BID; and nikkomycin Z at 100, 20, and 5 mg/kg/dose BID survived until the end of the study at day 17 postinfection, while 30% of the untreated vehicle control mice survived. Fungal burden assessed on survivors showed similar levels of Histoplasma antigen in lung and spleen homogenates of mice treated with amphotericin B at 2.0 mg/kg/dose QOD; itraconazole at 75 mg/kg/dose BID; and nikkomycin Z at 100, 20, and 5 mg/kg/dose BID. The three surviving vehicle control mice had significantly higher antigen levels in lung and spleen than other groups (P<0.05). The efficacy of nikkomycin Z at preventing mortality and reducing fungal burden correlates with in vitro susceptibility.

Dental fluorosis in children residing in communities with different water fluoride levels: 33-month follow-up

PURPOSE

The purpose of these examinations was to monitor changes, in the prevalence of dental fluorosis.

METHODS

In February 1992 and December 1994, children who were residents of one of three communities with varying levels of fluoride in their communal water supply were examined for dental fluorosis. Since some children were available at both examination periods, it was also possible to determine changes in the incidence of dental fluorosis.

RESULTS

The prevalence of fluorosis increased by approximately 14%, 20%, and 6% in the negligibly, optimally, and 4X optimally fluoridated communities, respectively. In the negligibly and optimally fluoridated communities, the incidence of dental fluorosis increased by 12% and 7%, respectively. In the 4X optimally fluoridated community, all the children examined had evidence of fluorosis at both examinations.

CONCLUSION

Fluoride continues to be the primary therapeutic agent for the prevention of dental caries in adults and children. With the downward adjustment in the fluoride supplement schedule, continued monitoring of the prevalence of dental fluorosis in young children is needed to determine if any additional steps are even necessary to restrict fluoride intake during the years that enamel formation is occurring.

Comparison of a new triazole antifungal agent, Schering 56592, with itraconazole and amphotericin B for treatment of histoplasmosis in immunocompetent mice

A murine model of intratracheally induced histoplasmosis was used to evaluate a new triazole antifungal agent, Schering (SCH) 56592, for treatment of histoplasmosis. MICs were determined for SCH 56592, amphotericin B, and itraconazole by testing yeast-phase isolates from 20 patients by a macrobroth dilution method. The MICs at which 90% of the isolates are inhibited were for 0.019 microgram/ml for SCH 56592, 0.5 microgram/ml for amphotericin B, and < or = 0.019 microgram/ml for itraconazole. Survival studies were done on groups of 10 B6C3F1 mice with a lethal inoculum of 10(5). All mice receiving 5, 1, or 0.25 mg of SCH 56592 per kg of body weight per day, 2.5 mg of amphotericin B per kg every other day (qod), or 75 mg of itraconazole per kg per day survived to day 29. Only 44% of mice receiving 5 mg of itraconazole/kg/day survived to day 29. Fungal burden studies done in similar groups of mice with a sublethal inoculum of 10(4) showed a reduction in CFUs and Histoplasma antigen levels in lung and spleen tissue in animals treated with 2 mg of amphotericin B/kg qod, 1 mg of SCH 56592/kg/day, and 75 mg of itraconazole/kg/day, but not in those treated with lower doses of the study drugs (0.2 mg of amphotericin B/kg qod, 0.1 mg of SCH 56592/kg/day, or 10 mg of itraconazole/kg/day). Serum drug concentrations were measured 3 and 24 h after the last dose in mice (groups of five to seven mice), each treated for 7 days with SCH 56592 (10 and 1 mg/kg/day) and itraconazole (75 and 10 mg/kg/day). Mean levels measured by bioassay were as follows: SCH 56592, 10 mg/kg/day (2.15 micrograms/ml at 3 h and 0.35 microgram/ml at 24 h); SCH 56592, 1 mg/kg/day (0.54 microgram/ml at 3 h and none detected at 24 h); itraconazole, 75 mg/kg/day (22.53 micrograms/ml at 3 h and none detected at 24 h); itraconazole, 10 mg/kg/day (1.33 micrograms/ml at 3 h and none detected at 24 h). Confirmatory results were obtained by high-pressure liquid chromatography assay. These studies show SCH 56592 to be a promising candidate for studies of treatment of histoplasmosis in humans.

The effect of mitomycin C on Molteno implant surgery: a 1-year randomized, masked, prospective study

PURPOSE

The authors assess whether adjunctive mitomycin C improves Molteno tube shunt surgery in terms of intraocular pressure (IOP), visual acuity, and complication rates.

PATIENTS AND METHODS

Twenty-five eyes of twenty-five consecutive patients undergoing double-plate Molteno implant surgery were randomized to receive either mitomycin C (MMC) 0.4 mg/mL for 2 minutes or a control balanced salt solution in a masked, prospective study. Intraocular pressure, visual acuity, and complications were recorded 1 week and 1, 3, 6, and 12 months after surgery. A repeated measures analysis of variance (ANOVA) model was used to test the overall effect of the drug on IOP and percent change from preoperative IOP.

RESULTS

Thirteen eyes received balanced salt solution and 12 eyes received MMC. There was no difference between the groups with respect to age, preoperative IOP, log mean angle of resolution (LogMar) visual acuity, or number of preoperative medications. Except for week 1, there were no differences between the groups at any of the clinic visits with respect to IOP and percent change from baseline IOP. Analysis of the visual acuity (LogMar) showed reduction in vision for both groups. Complications were similar in each group, as were number of postoperative hypotensive agents required.

CONCLUSIONS

Adjunct MMC does not demonstrate a significant difference in outcomes compared with placebo in pressure-ridged Molteno implant surgery. Results of this study are limited by a small number of patients in each group and a fixed dose of MMC.

Methadone maintenance in pregnancy: a reappraisal

OBJECTIVE

The purpose of this study is to evaluate women receiving methadone maintenance during pregnancy.

STUDY DESIGN

Thirty-two pregnancies in women receiving methadone maintenance were matched by gestational age to women with a positive urine screen for cocaine at delivery and to drug-free controls. Pregnancy outcome variables were compared, including birth weight and neonatal morbidity. Analysis was by chi2 and t test with significance set at .05.

RESULTS

Birth weight of methadone-exposed infants was 2748 g versus 2925 g for cocaine and 3032 g for controls, P = not significant. Birth weight comparison with a 50-mg maternal methadone cutoff dose was not different. A head circumference for methadone infants of 32.4 +/- 4.7 cm was significantly less than controls, 33.5 +/- 4.0 cm, P < .04, but not different from infants of cocaine users, 32.8 +/- 3.1 cm. Women using cocaine had a significantly higher incidence of meconium in labor compared with methadone and controls. Of women taking methadone 27 of 32 (84.3%) were positive for other drugs of abuse in the last screen before or at delivery. Cocaine 12 of 32 (37.5%), other opiates 13 of 32 (40.6%), and marijuana 14 of 32 (43.7%) were the most prevalent. Neonatal withdrawal occurred in 23 of 32 (72%) women taking methadone. The neonates of women using < 50 mg of methadone were as likely to withdraw as those women using > or = 50 mg, 61.5% versus 79.0%, P not significant. Three neonates in the methadone group (9.3%) had major congenital anomalies, with 2 of the 3 (66.6%) resulting in mortality.

CONCLUSIONS

Birth outcome is not significantly different between methadone and cocaine users. Women receiving methadone maintenance are likely to abuse other illicit drugs.

The effect of fluoride therapy on blood chemistry parameters in osteoporotic females

To determine the potential adverse effects, if any, of long-term fluoride ingestion in humans, samples were collected from 25 adult females taking daily doses of fluoride (mean, 23 mg elemental F) for the treatment of osteoporosis and from 38 osteoporotic female controls. Patients in the fluoride group had been receiving therapy for approximately 18 months with a mean duration of 4.2 years and had serum fluoride values of at least 10 mumol/l. Laboratory analyses for fluoride were conducted on plasma, urine and drinking water samples collected from each panelist. Blood was also collected for blood chemistry analyses and plasma lymphocytes were examined for the frequency of sister chromatid exchange (SCE). Plasma and urine fluoride levels were significantly different between the two groups, while water fluoride was not. The SCE frequency, a measurement of potential genotoxicity, did not differ between the two groups. Of the blood chemistry parameters measured, albumin, alkaline phosphatase, sodium, chloride, the albumin/globulin (A/G) ratio, indirect bilirubin, lactate dehydrogenase (LDH), and gamma-glutamyl transferase (GGT) were found to be significantly different between the two groups (P < or = 0.05). However, none of the mean group values were outside stated normal ranges for any of these parameters. We conclude that the risk of developing adverse systemic effects from the ingestion of fluoride, at dosages and for a duration comparable with that of our panel, is minimal.