The Growth Hormone Releasing Hormone Analogue, Tesamorelin, Decreases Muscle Fat and Increases Muscle Area in Adults with HIV

BACKGROUND

Tesamorelin, a growth hormone-releasing hormone analogue, decreases visceral adipose tissue in people living with HIV, however, the effects on skeletal muscle fat and area are unknown.

OBJECTIVES

The goals of this exploratory secondary analysis were to determine the effects of tesamorelin on muscle quality (density) and quantity (area).

DESIGN

Secondary, exploratory analysis of two previously completed randomized (2:1), clinical trials.

SETTING

U.S. and Canadian sites.

PARTICIPANTS

People living with HIV and with abdominal obesity. Tesamorelin participants were restricted to responders (visceral adipose tissue decrease ≥8%).

INTERVENTION

Tesamorelin or placebo.

MEASUREMENTS

Computed tomography scans (at L4-L5) were used to quantify total and lean density (Hounsfield Units, HU) and area (centimeters2) of four trunk muscle groups using a semi-automatic segmentation image analysis program. Differences between muscle area and density before and after 26 weeks of tesamorelin or placebo treatment were compared and linear regression models were adjusted for baseline and treatment arm.

RESULTS

Tesamorelin responders (n=193) and placebo (n=148) participants with available images were similar at baseline; most were Caucasian (83%) and male (87%). In models adjusted for baseline differences and treatment arm, tesamorelin was associated with significantly greater increases in density of four truncal muscle groups (coefficient 1.56-4.86 Hounsfield units; all p<0.005), and the lean anterolateral/abdominal and rectus muscles (1.39 and 1.78 Hounsfield units; both p<0.005) compared to placebo. Significant increases were also seen in total area of the rectus and psoas muscles (0.44 and 0.46 centimeters2; p<0.005), and in the lean muscle area of all four truncal muscle groups (0.64-1.08 centimeters2; p<0.005).

CONCLUSIONS

Among those with clinically significant decrease in visceral adipose tissue on treatment, tesamorelin was effective in increasing skeletal muscle area and density. Long term effectiveness of tesamorelin among people with and without HIV, and the impact of these changes in daily life should be further studied.

Isoniazid therapy for Mycobacterium tuberculosis infection in HIV clinics, Los Angeles, California

SETTING

Publicly funded human immunodeficiency virus (HIV) clinics in Los Angeles County, California, USA.

BACKGROUND

HIV-infected persons are a high priority group for targeted testing and treatment for Mycobacterium tuberculosis infection in the United States.

OBJECTIVE

To describe rates of isoniazid (INH) initiation and completion among HIV-1 and M. tuberculosis co-infected persons in Los Angeles County.

DESIGN

We conducted a cross-sectional study using routinely collected surveillance data from publicly funded HIV clinics. We examined differences in INH treatment initiation and completion between four clinic categories: the three largest clinics (Clinics A, B, and C) and 'Other' clinics (pooled data for the remaining 10 clinics).

RESULTS

During 2010-2013, 802 (5.3%) of 15 029 HIV-1-infected persons tested positive for M. tuberculosis infection. INH was initiated in 581 (72.4%) persons, of whom 457 (78.7%) completed treatment. We found significant differences between clinics in terms of treatment initiation (range 59.1-93.4%) and completion (range 58.8-82.3%). Overall, 57% (457/802) of HIV and M. tuberculosis co-infected persons completed the recommended treatment (range across clinics 34.8-76.3%).

CONCLUSION

We identified significant gaps in the treatment for M. tuberculosis infection among HIV-infected persons in Los Angeles County. Interventions are needed to improve initiation and completion of treatment for M. tuberculosis infection in this population.

Methylomic changes during conversion to psychosis

The onset of psychosis is the consequence of complex interactions between genetic vulnerability to psychosis and response to environmental and/or maturational changes. Epigenetics is hypothesized to mediate the interplay between genes and environment leading to the onset of psychosis. We believe we performed the first longitudinal prospective study of genomic DNA methylation during psychotic transition in help-seeking young individuals referred to a specialized outpatient unit for early detection of psychosis and enrolled in a 1-year follow-up. We used Infinium HumanMethylation450 BeadChip array after bisulfite conversion and analyzed longitudinal variations in methylation at 411 947 cytosine-phosphate-guanine (CpG) sites. Conversion to psychosis was associated with specific methylation changes. Changes in DNA methylation were significantly different between converters and non-converters in two regions: one located in 1q21.1 and a cluster of six CpG located in GSTM5 gene promoter. Methylation data were confirmed by pyrosequencing in the same population. The 100 top CpGs associated with conversion to psychosis were subjected to exploratory analyses regarding the related gene networks and their capacity to distinguish between converters and non-converters. Cluster analysis showed that the top CpG sites correctly distinguished between converters and non-converters. In this first study of methylation during conversion to psychosis, we found that alterations preferentially occurred in gene promoters and pathways relevant for psychosis, including oxidative stress regulation, axon guidance and inflammatory pathways. Although independent replications are warranted to reach definitive conclusions, these results already support that longitudinal variations in DNA methylation may reflect the biological mechanisms that precipitate some prodromal individuals into full-blown psychosis, under the influence of environmental factors and maturational processes at adolescence.

Cuckoo search epistasis: a new method for exploring significant genetic interactions

The advent of high-throughput sequencing technology has resulted in the ability to measure millions of single-nucleotide polymorphisms (SNPs) from thousands of individuals. Although these high-dimensional data have paved the way for better understanding of the genetic architecture of common diseases, they have also given rise to challenges in developing computational methods for learning epistatic relationships among genetic markers. We propose a new method, named cuckoo search epistasis (CSE) for identifying significant epistatic interactions in population-based association studies with a case-control design. This method combines a computationally efficient Bayesian scoring function with an evolutionary-based heuristic search algorithm, and can be efficiently applied to high-dimensional genome-wide SNP data. The experimental results from synthetic data sets show that CSE outperforms existing methods including multifactorial dimensionality reduction and Bayesian epistasis association mapping. In addition, on a real genome-wide data set related to Alzheimer's disease, CSE identified SNPs that are consistent with previously reported results, and show the utility of CSE for application to genome-wide data.

Replication of TPMT and ABCC3 genetic variants highly associated with cisplatin-induced hearing loss in children

Cisplatin is a widely used chemotherapeutic agent for the treatment of solid tumors. A serious complication of cisplatin treatment is permanent hearing loss. The aim of this study was to replicate previous genetic findings in an independent cohort of 155 pediatric patients. Associations were replicated for genetic variants in TPMT (rs12201199, P = 0.0013, odds ratio (OR) 6.1) and ABCC3 (rs1051640, P = 0.036, OR 1.8). A predictive model combining variants in TPMT, ABCC3, and COMT with clinical variables (patient age, vincristine treatment, germ-cell tumor, and cranial irradiation) significantly improved the prediction of hearing-loss development as compared with using clinical risk factors alone (area under the curve (AUC) 0.786 vs. 0.708, P = 0.00048). The novel combination of genetic and clinical factors predicted the risk of hearing loss with a sensitivity of 50.3% and a specificity of 92.7%. These findings provide evidence to support the importance of TPMT, COMT, and ABCC3 in the prediction of cisplatin-induced hearing loss in children.

Syringomyelia in cavalier King Charles spaniels: the relationship between syrinx dimensions and pain

OBJECTIVES

This study was designed to test the hypothesis that pain associated with syringomyelia in dogs is dependent upon size and involvement of the dorsal part of the spinal cord.

METHODS

Masked observers determined syrinx dimensions and precise location within the spinal cord on magnetic resonance images of 55 cavalier King Charles spaniels with syringomyelia. After removal of masking, syrinx size and location were compared between the cohorts of dogs that exhibited pain with those that did not.

RESULTS

Maximum syrinx width was the strongest predictor of pain, scratching behaviour and scoliosis in dogs with syringomyelia. Both pain and syrinx size were positively correlated with syrinxes located in the dorsal half of the spinal cord.

CLINICAL SIGNIFICANCE

Large syrinxes associated with damage to the dorsal part of the spinal cord are associated with persistent pain suggesting that the pain behaviour expressed by this group of patients is likely to be "neuropathic pain," resulting from disordered neural processing in the damaged dorsal horn. As such it is likely that conventional analgesic medication may be ineffective.

A novel autosomal dominant restless legs syndrome locus maps to chromosome 20p13

The authors investigated genetic factors contributing to restless legs syndrome (RLS) by performing a 10-cM genome-wide scan in a large French-Canadian pedigree. They detected an autosomal-dominant locus mapping to chromosome 20p13, with a maximum multipoint lod score of 3.86 at marker D20S849. This is the third reported autosomal-dominant locus for RLS and the first autosomal-dominant RLS locus in the French-Canadian population.

A new locus for autosomal dominant intracranial aneurysm, ANIB4, maps to chromosome 5p15.2-14.3

BACKGROUND

Intracranial aneurysms (IA) are dilatations of intracranial arteries that occur most commonly at arterial bifurcations. Unruptured IA are present in approximately 1-2% of the population aged over 30 years of age. Aneurysms are only rarely symptomatic unless they rupture, which typically results in a subarachnoid haemorrhage associated with high morbidity and mortality.

METHODS

A large French Canadian (FC) family (Aneu60) was identified which contained 12 affected individuals with intracranial aneurysms. Nine of the affected patients and three unaffected individuals were sent for an 8 cM genome-wide scan. Multipoint and two-point methods were used to analyse the scan data by using a dominant parametric model.

RESULTS

We identified an IA susceptibility locus (ANIB4) located on chromosome 5p15.2-14.3. The locus was found by genome-wide linkage analysis and follow up analyses provided a maximum multipoint LOD score of 3.57 over the region. An identical haplotype segment of 7.2 Mb was found in a second FC pedigree and contributes to the refinement of the candidate gene interval.

CONCLUSIONS

Our results indicate that there is a major gene locus on chromosome 5p.

Autism spectrum disorders associated with X chromosome markers in French-Canadian males

It is now well established that genetic factors play an important role in the pathogenesis of autism disorder and converging lines of evidence suggest the implication of the X chromosome. Using a sample of subjects diagnosed with autism spectrum disorders, exclusively composed of males from French-Canadian (FC) origin, we tested markers covering the entire X chromosome using a family-based association study. Our initial analysis revealed the presence of association at two loci: DXS6789 (P=0.026) and DXS8043 (P=0.0101). In a second step, we added support to the association at DXS8043 using additional markers, additional subjects and a haplotype-based analysis (best obtained P-value=0.00001). These results provide support for the existence of a locus on the X chromosome that predisposes the FC to autism spectrum disorders.

Prevalence of proteinuria and the development of chronic kidney disease in HIV-infected patients

AIMS

HIV-related renal diseases are increasingly prevalent and are associated with proteinuria and rapid progression to end-stage renal failure. Early treatment with highly active antiretroviral therapy (HAART) and ACE inhibition may prevent the development of chronic kidney disease (CKD), but studies evaluating the epidemiology of proteinuria and early CKD in HIV-infected patients are lacking.

METHODS

All consecutive patients at Wishard Memorial Hospital (Indiana University) whose initial HIV documentation occurred from 1990 to 1998, were retrospectively studied using a computerized medical record system. Clinical data were abstracted from time of first HIV documentation through 12/31/2000. The proportions of patients who developed CKD (doubling of serum creatinine from an initial level < or = 1.5 mg/dl) and who had proteinuria (> or = 1+ protein on the first urine dipstick after HIV documentation) were calculated. Case mix and laboratory variables at the time of HIV documentation were compared between those who did and did not develop CKD and between those who had and did not have initial proteinuria.

RESULTS

Of 487 subjects with initially normal renal function, 10 (2% (95% CI, 1-4%)) developed CKD. In univariable analysis, black race, a diagnosis of diabetes or hypertension and proteinuria were all significantly associated with the development of CKD; 89 (29% (95% CI, 24-35%)) of 289 evaluable subjects had > or = 1+ proteinuria on urine analysis. Multivariable regression revealed only older age (OR 1.08 per year increase; 95% CI, 1.03-1.14) to be associated with proteinuria.

CONCLUSIONS

A small, but potentially clinically meaningful proportion of HIV-infected patients develop CKD, and there appears to be a high prevalence of proteinuria on the first urine analysis obtained after HIV documentation.

Progesterone receptor variant increases ovarian cancer risk in BRCA1 and BRCA2 mutation carriers who were never exposed to oral contraceptives

Oral contraceptives have been shown to be protective against hereditary ovarian cancer. The variant progesterone receptor allele named PROGINS is characterized by an Alu insertion into intron G and two additional mutations in exons 4 and 5. The PROGINS allele codes for a progesterone receptor with increased stability and increased hormone-induced transcriptional activity. We studied the role of the PROGINS allele as a modifying gene in hereditary breast and ovarian cancer. The study included 195 BRCA1 and BRCA2 carriers with a prior diagnosis of ovarian cancer, 392 carriers with a diagnosis of breast cancer and 249 carriers with neither cancer. Fifty-eight women had both forms of cancer. Five hundred and ninety-five women had a BRCA1 mutation and 183 women had a BRCA2 mutation. Overall, there was no association between disease status and the presence of the PROGINS allele. Information on oral contraception use was available for 663 of the 778 carriers of BRCA1 or BRCA2 mutations. Among the 449 subjects with a history of oral contraceptive use (74 cases and 365 controls), no modifying effect of PROGINS was observed [odds ratio (OR) 0.8; 95% confidence interval (CI) 0.5-1.3]. Among the 214 carriers with no past exposure to oral contraceptives, the presence of one or more PROGINS alleles was associated with an OR of 2.4 for ovarian cancer, compared to women without ovarian cancer and with no PROGINS allele (P = 0.004; 95% CI 1.4-4.3). The association was present after adjustment for ethnic group and for year of birth.

A randomized study of the utility of human immunodeficiency virus RNA measurement for the management of antiretroviral therapy

To compare frequent measurement with infrequent measurement of human immunodeficiency virus (HIV) RNA levels in the management of antiretroviral therapy, we conducted a clinical strategy study of 206 HIV-infected patients who had <500 CD4 cells/mm(3). Patients were randomized (1.5:1) to undergo frequent monitoring (at baseline and every 2 months) or infrequent monitoring (at baseline and twice yearly), with CD4 cell counts determined every 2 months. Patients received unrestricted antiretroviral therapy. In the primary analysis (at month 6), the frequent group had a mean HIV RNA reduction (+/- standard deviation) of 0.93+/-0.79 log(10) copies/mL, versus 0.48+/-0.83 log(10) copies/mL for the infrequent group (P=.0002). A trend (P=.1) toward improved survival was seen in the frequent group. Given this improved virological response, more frequent HIV RNA measurement than is recommended in published guidelines (every 3-4 months) may be appropriate.

Prospective evaluation of the effect of initiating indinavir-based therapy on insulin sensitivity and B-cell function in HIV-infected patients

OBJECTIVE

To determine whether initiation of antiretroviral therapy that includes the protease inhibitor indinavir causes insulin resistance or abnormal B-cell function in study subjects with HIV infection.

METHODS

Nonwasted, HIV-infected study subjects who did not have concurrent diabetes were prospectively evaluated by oral and intravenous glucose tolerance testing at baseline, at 2 weeks after starting indinavir monotherapy, and at another 6 weeks after initiating indinavir-based triple-therapy.

RESULTS

Mean CD4 count at entry was 282 cells/microl and median HIV RNA was 33,000 copies/ml; all experienced a virologic response. Fasting glucose increased from 83.2 +/- 3.7 mg/dl at baseline to 86.8 +/- 3.2 at week 2 and 91.7 +/- 3.5 at week 8 (p =.003). Insulin sensitivity by minimal model analysis decreased by 30.5% over 8 weeks, from 3.83 +/- 0.63 min-1 per microU/ml x 10-4 to 3.09 +/- 0.53 at week 2 and 2.66 +/- 0.35 at week 8 (p =.01). Insulin secretion by the acute insulin response to intravenous glucose did not change (baseline 822 +/- 283 microU/ml x min, week 8 880 +/- 289; p = 0.4), and the insulin response to oral glucose (30 minute insulin:glucose ratio) fell from 1.69 +/- 0.54 microU/ml per mg/dl at baseline to 1.18 +/- 0.34 at week 8 (p =.05).

CONCLUSION

During 8 weeks of indinavir-based therapy, fasting glucose increased and insulin sensitivity decreased, without a compensatory increase in insulin release. This combination of insulin resistance without augmented B-cell response may explain the hyperglycemia and other metabolic abnormalities seen in some protease inhibitor-treated patients.

Sequencing of protease inhibitor therapy: insights from an analysis of HIV phenotypic resistance in patients failing protease inhibitors

OBJECTIVE

To characterize the pattern of HIV-1 susceptibility to protease inhibitors in patients failing an initial protease inhibitor-containing regimen.

DESIGN

A cross-sectional analysis of antiretroviral susceptibility.

SETTING

HIV clinics in six metropolitan areas.

PATIENTS

Eighty-eight HIV-infected adults with HIV RNA > 400 copies/ml after > or = 6 months of antiretroviral therapy, including the use of one protease inhibitor for > or = 3 months.

MEASUREMENTS

The frequency and magnitude of decreased susceptibility, measured with a phenotypic assay using recombinant constructs, to five protease inhibitors. Decreased susceptibility was defined as > 2.5-fold increase in the 50% inhibitory concentration (IC50) compared with drug sensitive control virus.

RESULTS

At study entry, patients were being treated with nelfinavir (63%), indinavir (25%), or another protease inhibitor (11%). HIV isolates from these patients were susceptible (fold change < 2.5) to all five protease inhibitors in 18% of patients and to none in 8%. Isolates from patients receiving nelfinavir were less likely to have reduced susceptibility to other protease inhibitors than isolates from patients treated with indinavir (P < 0.001) or one of the other three agents (P < 0.001), even after adjustment for the duration of prior protease inhibitor use. Reduced susceptibility to saquinavir and amprenavir was observed significantly less frequently than for the other protease inhibitors.

CONCLUSION

The frequency of protease inhibitor cross-resistance and the magnitude of changes in susceptibility varied according to the initial protease inhibitor used in the failing treatment regimen. Significantly less protease inhibitor cross-resistance was demonstrated for isolates from patients failing a nelfinavir-containing regimen compared with those from patients receiving other protease inhibitors.

Disorders of glucose metabolism in patients infected with human immunodeficiency virus

New-onset diabetes mellitus, clinically similar to type 2 diabetes, will affect a small proportion (1%-6%) of patients infected with human immunodeficiency virus (HIV) who are treated with HIV-1 protease inhibitors (PIs). However, insulin resistance and impaired glucose tolerance will develop during PI treatment in a considerable proportion of patients. Dyslipidemia, abdominal obesity, and loss of peripheral fat frequently coexist with insulin resistance, but it is not clear whether all of these result from a common pathogenic mechanism. Recent data suggest that insulin resistance may also be associated with HIV infection in patients not receiving PI therapy. The long-term consequences of insulin resistance in this population are not known. The effect of switching to other antiretroviral therapies has not been fully determined. Treatment of established diabetes mellitus should generally follow existing guidelines. There is no clinically useful screening test that will determine the existence and degree of insulin resistance in individual patients. It is therefore reasonable to recommend general measures to increase insulin sensitivity in all patients infected with HIV, such as weight reduction for obese persons and regular aerobic exercise.

Preliminary guidelines for the evaluation and management of dyslipidemia in adults infected with human immunodeficiency virus and receiving antiretroviral therapy: Recommendations of the Adult AIDS Clinical Trial Group Cardiovascular Disease Focus Group

Dyslipidemia is a prevalent condition that affects patients infected with human immunodeficiency virus (HIV) who are receiving antiretroviral therapy. These preliminary recommendations summarize the current understanding in this area and propose guidelines for management. Existing guidelines for the management of dyslipidemia in the general population formed the general basis for our recommendations. Data on the prevalence and treatment of dyslipidemia of HIV-infected patients, implications of treatment-related dyslipidemia in other chronically ill populations, and pharmacokinetic profiles for the available hypolipidemic agents in non-HIV populations were considered. Although the implications of dyslipidemia in this population are not fully known, the frequency, type, and magnitude of lipid alterations in HIV-infected people are expected to result in increased cardiovascular morbidity. We propose that these patients undergo evaluation and treatment on the basis of existing guidelines for dyslipidemia, with the caveat that avoidance of interactions with antiretroviral agents is paramount.

Clouston hidrotic ectodermal dysplasia (HED): genetic homogeneity, presence of a founder effect in the French Canadian population and fine genetic mapping

HED is an autosomal dominant skin disorder that is particularly common in the French Canadian population of south-west Quebec. We previously mapped the HED gene to the pericentromeric region of chromosome 13q using linkage analysis in eight French Canadian families. In this study, we extend our genetic analysis to include a multiethnic group of 29 families with 10 polymorphic markers spanning 5.1 cM in the candidate region. Two-point linkage analysis strongly suggests absence of genetic heterogeneity in HED in four families of French, Spanish, African and Malaysian origins. Multipoint linkage analysis in all 29 families generated a peak lod score of 53.5 at D13S1835 with a 1 lod unit support interval spanning 1.8 cM. Recombination mapping placed the HED gene in a 2.4 cM region flanked by D13S1828 proximally and D13S1830 distally. We next show evidence for a strong founder effect in families of French Canadian origin thereby representing the first example of a founder disease in the south-west part of the province of Quebec. Significant association was found between HED in these families and all markers analysed (Fisher's exact test, P < 0.001). Complete allelic association was detected at D13S1828, D13S1827, D13S1835, D13S141 and D13S175 (P(excess) = 1) spanning 1.3 cM. A major haplotype including all 10 associated alleles was present on 65% of affected chromosomes. This haplotype most likely represents the founder haplotype that introduced the HED mutation into the French Canadian population. Luria-Delbrück equations and multipoint likelihood linkage disequilibrium analysis positioned the gene at the D13S1828 locus (likely range estimate: 1.75 cM) and 0.58 cM telomeric to this marker (support interval: 3.27 cM) respectively.

Efficacy of azithromycin in prevention of Pneumocystis carinii pneumonia: a randomised trial. California Collaborative Treatment Group

BACKGROUND

Azithromycin in combination with sulphonamides is active against Pneumocystis carinii pneumonia (PCP) in animals. We assessed the clinical efficacy of azithromycin for PCP prophylaxis in human beings.

METHODS

We identified HIV-1-infected patients with PCP during a prospective randomised trial comparing azithromycin, rifabutin, and the two drugs in combination for prevention of disseminated Mycobacterim avium infection. Patients had CD4-cell counts less than 100/microL at entry and received PCP prophylaxis according to the standard practice of their clinician. Analysis was by intention to treat.

FINDINGS

Patients receiving azithromycin, either alone (n=233) or in combination with rifabutin (n=224), had a 45% lower risk of developing PCP than those receiving rifabutin alone (n=236; p=0.008). Compared with rifabutin alone, hazard ratio for azithromycin was 0.54 (95% CI 0.32-0.94), for azithromycin plus rifabutin was 0.55 (0.32-0.94), and for regimens containing azithromycin was 0.55 (0.35-0.86). The most common side-effects involved the gastrointestinal tract with dose-limiting toxicities, and were mainly seen in patients receiving combination therapy.

INTERPRETATION

Azithromycin as prophylaxis for M. avium complex disease provides additional protection against P. carinii over and above that of standard PCP prophylaxis. Use of azithromycin is beneficial only as primary prophylaxis.

The value of patient-reported adherence to antiretroviral therapy in predicting virologic and immunologic response. California Collaborative Treatment Group

OBJECTIVE

To correlate self-reported antiretroviral adherence with virologic suppression.

DESIGN

Prospective observational study of adherence to therapy nested in a randomized comparative trial of frequent versus infrequent monitoring of plasma HIV RNA.

SETTING

Five university-affiliated HIV clinics.

PATIENTS

A group of 173 HIV-infected patients with a mean baseline CD4 count of 142 x 10(6) cells/l (range 3-515) of whom 164 and 119 completed adherence questionnaires at 2 and 6 months, respectively.

INTERVENTION

Individualized, unrestricted antiretroviral therapy.

MEASUREMENTS

Patients were classified into four groups by adherence to therapy in the previous 4 weeks (< 80%, 80-95%, 95-99%, 100%). Plasma HIV RNA levels and CD4 lymphocyte counts were measured bimonthly.

RESULTS

Recreational drug or alcohol use was associated with decreased adherence, whereas frequency of HIV RNA monitoring, demographic variables, (age, gender, education, and risk group) and stage of disease had no effect. Greater HIV suppression at 6 months was seen across four categories of increasing adherence (P = 0.009 for linear trend). Patients reporting < 80% adherence at 6 months had a 0.2 log10 copies/ml increase in HIV RNA and a loss of 19 x 10(6) CD4 cells/l compared with a 1.1 log10 copies/ml decrease in HIV RNA and an increase of 72 x 10(6) CD4 cells/l in those reporting 100% adherence (P = 0.02).

CONCLUSION

Self-reported poor adherence (< 80%) and drug or alcohol use predicted non-response of HIV RNA at 6 months of antiretroviral therapy.

Pharmacokinetics of trimetrexate and dapsone in AIDS patients with Pneumocystis carinii pneumonia

The objective of this study was to determine the pharmacokinetics of trimetrexate and dapsone in AIDS patients with moderate to severe pneumocystis pneumonia. Trimetrexate, leucovorin, and dapsone were administered for 21 +/- 3 days in the following doses: trimetrexate glucuronate, 45 mg/m2; leucovorin, 20 mg/m2; and dapsone, 100 mg daily. The pharmacokinetics of trimetrexate, dapsone, and dapsone's metabolite, monoacetyldapsone, were determined at three separate periods over the course of treatment. Serial blood samples were obtained over 24 hours after dosing and analyzed for trimetrexate, dapsone, and monoacetyldapsone, and pharmacokinetic parameters were determined. The mean parameters obtained for the early, mid-, and late collection periods were the following: trimetrexate: t1/2 = 8.29, 9.15, 10.00 hr; AUC = 16.85, 22.38, 24.49 mg.hr/l; CI = 5.58, 4.14, 3.96 l/hr, respectively. DDS: t1/2 = 14.99, 16.59, 15.13 hr; AUC = 30.60, 35.29, 36.08 mg.hr/l; CI = 3.82, 3.49, 3.01 l/hr, respectively. Monoacetyldapsone: t1/2 = 20.25, 18.66, 16.32 hr; AUC = 24.05, 24.06, 23.86 mg.hr/l, respectively. No statistically significant changes in pharmacokinetics for trimetrexate or dapsone were observed over the 21 +/- 3 day course of treatment. The results suggest that there are no major interactions between trimetrexate and dapsone when administered together in acutely ill patients.

Successful short-term suppression of clarithromycin-resistant Mycobacterium avium complex bacteremia in AIDS. California Collaborative Treatment Group

During a randomized study of clarithromycin plus clofazimine with or without ethambutol in patients with AIDS and Mycobacterium avium complex (MAC) bacteremia, eight participants received additional antimycobacterial drugs following the detection of a clarithromycin-resistant isolate (MIC, > 8 micrograms/mL). A macrolide (seven received clarithromycin, one azithromycin) and clofazimine were continued; additional treatment included various combinations of ethambutol, ciprofloxacin, amikacin, and rifabutin. After the detection of a resistant isolate and before receipt of additional antimycobacterials, the median peak MAC colony count in blood was 105 cfu/mL (range, 8-81,500 cfu/mL). After additional antimycobacterials, the median nadir MAC colony count was 5 cfu/mL (range, 0-110 cfu/mL). Five (63%) of eight patients had a > or = 1 log10 decrease, including two who achieved negative blood cultures; all of these responses occurred in patients originally assigned to clarithromycin plus clofazimine. Treatment of clarithromycin-resistant MAC bacteremia that emerges during clarithromycin-based treatment can decrease levels of bacteremia and transiently sterilize blood cultures.

Prophylaxis with weekly versus daily fluconazole for fungal infections in patients with AIDS

We compared the efficacy of a 400-mg once-weekly dosage versus a 200-mg daily dosage of fluconazole for the prevention of deep fungal infections in a multicenter, randomized, double-blind trial of 636 human immunodeficiency virus-infected patients to determine if a less intensive fluconazole regimen could prevent these serious but relatively infrequent complications of AIDS. In the intent-to-treat analysis, a deep fungal infection developed in 17 subjects (5.5%) randomly assigned to daily fluconazole treatment and in 24 (7.7%) given weekly fluconazole during 74 weeks of follow-up (risk difference, 2.2%; 95% confidence interval [CI], -1.7% to 6.1%). Thrush occurred twice as frequently in the weekly versus daily fluconazole recipients (hazard ratio, 0.59; 95% CI, 0.40-0.89), and in a subset of patients evaluated, fluconazole resistance was infrequent. Fluconazole administered once weekly is effective in reducing deep fungal infections in patients with AIDS, but this dosage is less effective than the 200-mg-daily dosage in preventing thrush.

A randomized evaluation of ethambutol for prevention of relapse and drug resistance during treatment of Mycobacterium avium complex bacteremia with clarithromycin-based combination therapy. California Collaborative Treatment Group

Patients with AIDS and Mycobacterium avium complex (MAC) bacteremia are at high risk for relapse and emergence of resistant isolates during monotherapy with clarithromycin. Ninety-five AIDS patients with MAC bacteremia received clarithromycin plus clofazimine, with or without ethambutol, in a prospective, multicenter, randomized open-label trial. Of 80 patients with positive baseline cultures, sterilization or a 2 log10 reduction in colony-forming units of MAC in two consecutive blood cultures occurred in 69% of both groups. There were nine relapses in the two-drug arm and three in the three-drug arm. Kaplan-Meier estimates of risk of relapse at 36 weeks were 68% and 12%, respectively (P = .004). All relapse isolates were resistant to clarithromycin. Median time to clarithromycin resistance was 16 weeks with two drugs and 40 weeks with three drugs (P = .004). Ethambutol reduced relapses and emergence of clarithromycin resistance and should be considered an essential component of clarithromycin-based therapies for MAC bacteremia.

Genomic structure of the human GT334 (EHOC-1) gene mapping to 21q22.3

Several inherited diseases have been mapped to the distal tip of human chromosome 21. In our recent efforts to clone candidate genes for some of these disorders, we have assembled a cosmid and BAC contig spanning 770 kb. We have identified expressed sequences from this contig by means of a cDNA hybrid selection scheme. We present here the isolation, cDNA sequence, genomic organization, and polymorphisms analysis of one such expressed sequence, GT334, which had been identified independently and designated EHOC-1. GT334 is split into 23 exons, and spans an estimated 95 kb of genomic DNA. A pseudogene of the histone H2AZ gene has been identified, and maps within the third intron. We have identified an ORF potentially encoding a protein 1259 amino acids in length, longer than that described in the EHOC-1 gene. The GT334 gene was screened for single base pair changes using single-strand conformation polymorphism (SSCP) analysis and we have identified seven sequence variations within this gene. These polymorphisms can be used as markers in the genetic mapping of other diseases localized to this region.

Hereditary spastic paraplegia: LOD-score considerations for confirmation of linkage in a heterogeneous trait

Hereditary spastic paraplegia (HSP) is a degenerative disorder of the motor system, defined by progressive weakness and spasticity of the lower limbs. HSP may be inherited as an autosomal dominant (AD), autosomal recessive, or an X-linked trait. AD HSP is genetically heterogeneous, and three loci have been identified so far: SPG3 maps to chromosome 14q, SPG4 to 2p, and SPG4a to 15q. We have undertaken linkage analysis with 21 uncomplicated AD families to the three AD HSP loci. We report significant linkage for three of our families to the SPG4 locus and exclude several families by multipoint linkage. We used linkage information from several different research teams to evaluate the statistical probability of linkage to the SPG4 locus for uncomplicated AD HSP families and established the critical LOD-score value necessary for confirmation of linkage to the SPG4 locus from Bayesian statistics. In addition, we calculated the empirical P-values for the LOD scores obtained with all families with computer simulation methods. Power to detect significant linkage, as well as type I error probabilities, were evaluated. This combined analytical approach permitted conclusive linkage analyses on small to medium-size families, under the restrictions of genetic heterogeneity.

Pneumocystis carinii pneumonia masquerading as tuberculosis

Recent laboratory studies indicate that genetic diversity exists in human strains of Pneumocystis carinii. Structural and functional variability in infecting strains could result in differences in host-parasite interactions and the natural history of P carinii pneumonia. We report 5 unusual cases in which the clinical presentation mimicked tuberculosis. All patients were cared for at a university-based public hospital clinic in Los Angeles, Calif, during a 2-year period. These patients were chronically ill, had lost weight, and each had cavities or cystic spaces as the primary radiographic findings. None were receiving aerosol pentamidine and only one had a history of smoking. Four patients were initially treated for tuberculosis and the fifth for disseminated Mycobacterium avium complex. Pneumocystis carinii was the only pathogen identified in each case. The unusual clinical presentations delayed the diagnosis of P carinii in all 5 cases. Practitioners must be aware of the variable presentations of P carinii pneumonia.

Prophylaxis against disseminated Mycobacterium avium complex with weekly azithromycin, daily rifabutin, or both. California Collaborative Treatment Group

BACKGROUND

Azithromycin is active in treating Mycobacterium avium complex disease, but it has not been evaluated as primary prophylaxis in patients with human immunodeficiency virus (HIV) infection. Because the drug is concentrated in macrophages and has a long half-life in tissue, there is a rationale for once-weekly dosing.

METHODS

We compared three prophylactic regimens in a multicenter, double-blind, randomized trial involving 693 HIV-infected patients with fewer than 100 CD4 cells per cubic millimeter. The patients were assigned to receive rifabutin (300 mg daily), azithromycin (1200 mg weekly), or both drugs. They were monitored monthly with blood cultures for M. avium complex.

RESULTS

In an intention-to-treat analysis, the incidence of disseminated M. avium complex infection at one year was 15.3 percent with rifabutin, 7.6 percent with azithromycin, and 2.8 percent with both drugs. The risk of the infection in the azithromycin group was half that in the rifabutin group (hazard ratio, 0.53; P = 0.008). The risk was even lower when two-drug prophylaxis was compared with rifabutin alone (hazard ratio, 0.28; P<0.001) or azithromycin alone (hazard ratio, 0.53; P = 0.03). Among the patients in whom azithromycin prophylaxis was not successful, 11 percent of M. avium complex isolates were resistant to azithromycin. Dose-limiting toxic effects were more common with the two-drug combination than with azithromycin alone (hazard ratio, 1.67; P=0.03). Survival was similar in all three groups.

CONCLUSIONS

For protection against disseminated M. avium complex infection, once-weekly azithromycin is more effective than daily rifabutin and infrequently selects for resistant isolates. Rifabutin plus azithromycin is even more effective but is not as well tolerated.

DNA fingerprinting of Candida rugosa via repetitive sequence-based PCR

A repetitive sequence-based PCR (rep-PCR) technique was developed to characterize the genotypic relatedness among Candida rugosa isolates. Two repetitive sequences, viz., Care-2 and Com29 from Candida albicans, were used to design primers Ca-21, Ca-22, and Com-21, respectively. When used alone or in combination, these primers generated discriminatory fingerprints by amplifying the adjacent variable regions of the genome. Twenty-three isolates from burn patients, eight from other human sources, and four C. rugosa isolates pathogenic in animals were placed into nine fingerprinting groups. Different primers placed these isolates into identical groups, indicating that rep-PCR is a specific and reproducible technique for molecular characterization of C. rugosa. Moreover, these primers unequivocally discriminated among other important Candida species such as C. albicans, C. glabrata, C. tropicalis, C. krusei, C. parapsilosis, C. kefyr, and C. lusitaniae. These data confirm the conservation of repetitive sequences in Candida species. Because of its ease and sensitivity, rep-PCR offers a relatively rapid and discriminatory method for molecular typing of C. rugosa in outbreaks.

Hereditary spastic paraplegia: advances in genetic research. Hereditary Spastic Paraplegia Working group

Hereditary spastic paraplegia (HSP) is a diverse group of inherited disorders characterized by progressive lower-extremity spasticity and weakness. Insight into the genetic basis of these disorders is expanding rapidly. Uncomplicated autosomal dominant, autosomal recessive, and X-linked HSP are genetically heterogeneous: different genes cause clinically indistinguishable disorders. A locus for autosomal recessive HSP is on chromosome 8q. Loci for autosomal dominant HSP have been identified on chromosomes 2p, 14q, and 15q. One locus (Xq22) has been identified for X-linked, uncomplicated HSP and shown to be due to a proteolipoprotein gene mutation in one family. The existence of HSP families for whom these loci are excluded indicates the existence of additional, as yet unidentified HSP loci. There is marked clinical similarity among HSP families linked to each of these loci, suggesting that gene products from HSP loci may participate in a common biochemical cascade, which, if disturbed, results in axonal degeneration that is maximal at the ends of the longest CNS axons. Identifying the single gene defects that cause HSPs distal axonopathy may provide insight into factors responsible for development and maintenance of axonal integrity. We review clinical, genetic, and pathologic features of HSP and present differential diagnosis and diagnostic criteria of this important group of disorders. We discuss polymorphic microsatellite markers useful for genetic linkage analysis and genetic counseling in HSP.

Fungemia and colonization with nystatin-resistant Candida rugosa in a burn unit

Yeast isolates from burned patients were analyzed retrospectively for a 7-year period (1984-1991). Topical nystatin was used routinely in the burn wound dressing as antifungal therapy beginning in July 1986. Nystatin used was associated with a significant decrease in overall yeast acquisitions in burn wounds; yeasts were isolated from 15.5% of admitted patients before the use of nystatin vs. 10.5% with use of nystatin (odds ratio [OR] = 0.64; 95% confidence interval [CI], 0.48-0.86). New acquisitions of Candida rugosa in burn wounds increased from 0.36% of admissions during the period July 1984 to June 1986 (before nystatin use) to 5.25% in the period July 1986 to June 1991 (during use of nystatin) (OR = 15.3; 95% CI, 4.1-128). The incidence of fungemia decreased from 3.25% of admissions in the pre-nystatin period to 1.43% in the postnystatin period (OR = 0.43; 95% CI, 0.22-0.87). C. rugosa caused none of 18 fungemias in the former period and 15 of 21 in the latter period (P = .002). Susceptibility testing of recent C. rugosa isolates demonstrated resistance to nystatin and moderate susceptibility to amphotericin B and fluconazole. Topical nystatin use was associated with a decrease in fungemias and acquisition of yeasts in burn wounds but with an increase in colonization and fungemias caused by nystatin-resistant, amphotericin B-susceptible C. rugosa.

Tuberculous meningitis in patients with and without human immunodeficiency virus infection

OBJECTIVE

To characterize the symptoms, signs, laboratory findings, and outcome of culture-proven meningitis due to Mycobacterium tuberculosis in patients with and without human immunodeficiency virus (HIV) infection.

DESIGN

Retrospective chart review.

SETTING

Urban public general hospital in the United States.

PATIENTS

Fifteen patients with and 16 without HIV infection.

MEASUREMENTS

Demographics, symptoms, physical exam findings, serum sodium, complete blood cell count, CD4+ cell count, cerebrospinal fluid findings, imaging data, and in-hospital mortality.

MAIN RESULTS

Symptoms, signs, chest radiograph appearance, cerebrospinal fluid cell counts and chemistries, and mortality were similar in both groups (p = NS). Median CD4+ cell counts were lower in HIV-infected patients (median 99/mm3, range 7 to 251, versus 384/mm3, range 171 to 724 in those without HIV infection, p = 0.007). Intracerebral mass lesions were more common in the HIV-infected group (60% versus 14% in the uninfected group, p = 0.01), although the presence of a mass did not correlate with focal neurologic deficits, altered level of consciousness, or mortality.

CONCLUSION

With the exception of an increased incidence of intracerebral mass lesions in HIV-infected individuals, HIV infection appears to have little impact on the findings and in-hospital mortality of tuberculous meningitis.