Decompression, fusion, and instrumentation surgery for complex lumbar spinal stenosis

Between 1990 and 1993, 54 consecutive patients were treated with decompression, fusion and instrumentation surgery for complex lumbar spinal stenosis. The mean age of the patients was 60 years. The average followup was 39 months. Clinically, there was one deep wound infection, and three mechanical failures. There were two staged operations. There were three revision surgeries performed for mechanical reasons. Of the 47 patients who completed the questionnaire, 96% of patients were very satisfied or somewhat satisfied with the operation, 98% were satisfied with relief of pain, 94% were satisfied with their ability to walk, 89% were satisfied with their strength, and 94% were satisfied with balance. Survivorship analysis (failure endpoint was revision surgery) revealed that at the end of 4 years, the patient had a 92% chance of not undergoing revision surgery for any reason (mechanical and infectious), and a 94% chance of not undergoing revision surgery for mechanical reasons. Lumbar decompression, fusion, and instrumentation surgery seems to be efficacious in patients with complex lumbar spinal stenosis (associated previous lumbar spine operations with evidence of radiographic instability, radiographic evidence of junctional stenosis after surgery, radiographic evidence of instability, degenerative spondylolisthesis greater than Grade I with instability, if present, and degenerative scoliosis with a curve greater than 20 degrees).

Decompressive surgery for typical lumbar spinal stenosis

Between 1991 and 1992, 103 consecutive patients (average age, 65 years) underwent decompressive surgery for treatment of typical lumbar spinal stenosis. Clinical results at 1-year followup revealed that four patients had revision surgery. At 2- to 5-years followup, there were no additional revision surgeries. Two patients underwent revision surgery for a deep infection, and two underwent revision surgery for a superficial infection. Outcome results showed that 77 patients completed the questionnaire, 15 were lost to followup and 11 died. Postoperative results showed that 64 of 77 patients had no or mild pain, 72 of 77 patients stated that they were satisfied or somewhat satisfied with their overall results of surgery, and 73 of 77 were satisfied with pain relief. Younger patients had greater improvement in function and a greater reduction in severity scores. However, satisfaction was similar in both groups. Survivorship results (failure was revision surgery) showed at the end of 4 years, a patient had a 95% chance of not having revision surgery. Statistically, there was no association between outcome and cofactors such as scoliosis, spondylolisthesis, number of levels decompressed, discectomy, or smoking. Satisfaction rates for older patients were similar to patients younger than 65 years although physical function scores and severity scores were less.

Fetal diagnosis and management of congenital heart disease

Fetal echocardiography has had a significant impact on the diagnosis and management of congenital heart disease. Although the fetal circulation is quite forgiving for many heart lesions, other flow abnormalities gravely affect fetal physiology. Serial studies have given us a window to observe the natural history of many lesions that progress during gestation. Although fetal cardiac surgery is not yet a viable alternative to neonatal repair, fetal intervention on noncardiac disorders has had limited success and the field is growing. Fetal diagnosis remains an integral part of the management of children with cardiac lesions.

The collateral ligaments of the elbow: anatomy and clinical correlation

Stability of the elbow is provided by the congruous nature of the bony articulations and the medial and lateral collateral ligament complexes. The medial ligament provides additional support to valgus stress. The lateral ligament prevents rotational instability between the distal humerus and the proximal radius and ulna. Collateral ligament insufficiency typically is posttraumatic and can occur on either side of the joint. An understanding of the normal anatomy is required to make the correct diagnosis and complete a successful surgical reconstruction.

Closed reduction and percutaneous pinning of fractures of the proximal phalanx

This study reports the results of 12 unstable extraarticular fractures of the proximal phalanx treated with transarticular intramedullary Kirschner wires. Early proximal interphalangeal joint motion was allowed and all patients achieved uneventful union, with an average total active motion of 265 degrees. Objective physical assessment revealed one significant flexion contracture, one flexor tendon adhesion and one significant rotational deformity. Excellent results were observed in ten of the 12 patients.

Adequacy of fellowship training: results of a survey of recently graduated fellows

The adequacy of fellowship training in the field of infectious diseases was assessed by means of a survey of recently graduated fellows. Surveys were mailed to all individuals who had passed the American Board of Internal Medicine's board certification examination in infectious diseases since 1992. A total of 666 completed surveys were returned by the deadline (response rate, 36%). Although most recent graduates thought that training in the standard components of clinical infectious diseases was adequate, only 50% thought that training in infection control was adequate. Fewer than 1 in 3 believed that they had received adequate training in the business aspects of infectious diseases practice. The adequacy and duration of research training were linked to ultimate career choice. These results form the basis for the Infectious Diseases Society of America's new initiatives to assist with more-diversified and relevant fellowship training.

Syndromic treatment of gonococcal and chlamydial infections in women seeking primary care for the genital discharge syndrome: decision-making

The syndromic treatment of gonococcal and chlamydial infections in women seeking primary care in clinics where resources are scarce, as recommended by WHO and implemented in many developing countries, necessitates a balance to be struck between overtreatment and undertreatment. The present paper identifies factors that are relevant to the selection of specific strategies for syndromic treatment in the above circumstances. Among them are the general aspects of decision-making and caveats concerning the rational decision-making approach. The positive and negative implications are outlined of providing or withholding treatment following a specific algorithm with a given accuracy to detect infection, i.e. sensitivity, specificity and predictive values. Other decision-making considerations that are identified are related to implementation and include the stability of risk factors with regard to time, space and the implementer, acceptability by stakeholders, and environmental constraints. There is a need to consider empirically developed treatment algorithms as a basis for policy discourse, to be evaluated together with the evidence, alternatives and arguments by the stakeholders.

Structure-function correlation of laminar vascularity in human rectus extraocular muscles

PURPOSE

Orbital and global layers of rectus extraocular muscles (EOMs) are believed to serve different functions. This study sought anatomic and functional evidence of differing blood flow in the two layers of rectus EOMs.

METHODS

Four human orbits ranging in age from 17 months to 93 years were serially sectioned and stained for muscle fibers with Masson's trichrome and for vascular smooth muscle with monoclonal antibody to smooth muscle alpha-actin. Digitally assisted microscopy was used to obtain measurements of luminal cross sections and counts of muscular blood vessels, as well as measurements of muscle fiber number and cross-sectional areas of the two layers. Findings were correlated with first-pass gadodiamide contrast magnetic resonance imaging (MRI) in two living humans to demonstrate relative perfusion of EOMs.

RESULTS

In all rectus EOMs, the orbital layer had significantly more vessels per unit area, more vessels per fiber, and more total vascular luminal area, than the global layer (P: < 0.05). Vascularity of EOMs was greatest in the youngest specimen. First-pass contrast MRI was consistent with perfusion of the orbital layer earlier than the global layer of living human rectus EOMs.

CONCLUSIONS

Orbital layers of human rectus EOMs have significantly more muscular vessels than the global layers and stain earlier after intravenous bolus injection of paramagnetic MRI contrast. These findings suggest higher and even more rapid blood flow in the orbital layers that may correlate with greater metabolic activity. Greater blood flow is consistent with more sustained mechanical loading of the orbital than the global layer.

Degenerative arthritis of the wrist: proximal row carpectomy versus scaphoid excision and four-corner arthrodesis

Two cohort populations of 19 patients from separate institutions performing exclusively either a scaphoid excision and 4-corner arthrodesis (lunate, capitate, hamate, and triquetrum) or proximal row carpectomy (PRC) for scapholunate advanced collapse arthritis were compared. There were no preoperative differences with respect to age, gender, dominance, stage of arthritis, or preoperative measures of pain and function. The length of the follow-up period averaged 28 months for the 4-corner arthrodesis group compared with 19 months for the PRC patients. At the follow-up examination wrist motion revealed no significant differences in the flexion-extension arc, averaging 81 degrees in the PRC patients and 80 degrees following 4-corner arthrodesis, which was 62% and 58%, respectively, of the opposite wrist. The 4-corner arthrodesis patients maintained greater radial deviation and total percent radial-ulnar deviation of the wrist. Grip strength averaged 71% for the PRC group compared with 79% for the 4-corner arthrodesis patients. Pain relief was similar using a variety of measures and patient satisfaction was equivalent. Function was similar except that the 4-corner arthrodesis patients scored significantly higher on the mental health component of the short form-36 health status survey. No differences were seen on the physical health component or an outcome scale specifically designed for the wrist. Both PRC and scaphoid excision and 4-corner arthrodesis are motion-preserving options for the treatment of scapholunate advanced collapse arthritis with minimal subjective or objective differences in short-term follow-up evaluations.

Bone graft harvesting from the distal radius, olecranon, and iliac crest: a quantitative analysis

The purpose of this study was to quantify the volume and density of cancellous bone available from 3 commonly used bone graft sites in upper extremity surgery: the distal radius, olecranon process, and anterior iliac crest. Sixteen cadavers (age range, 59-98 years) with no prior history of bone harvest or metabolic conditions affecting bone were used. Cancellous graft was obtained using standardized techniques designed to simulate the clinical setting. Packed cancellous bone volume was determined as the volume occupied by the harvested bone after compression packing with a uniform load. Defect volume was determined by measuring the volume of the site from which bone was harvested. The distal radius and olecranon provided similar volumes of packed cancellous bone (2.7 and 2.8 cc, respectively). The anterior iliac crest provided approximately twice this amount (5.3 cc). The packed cancellous bone volume/defect volume ratio was not different between the 3 sites studied. Male gender was associated with a significantly greater amount of packed cancellous bone volume for all sites. We believe the olecranon to be an alternative to the distal radius as a source of bone graft for upper extremity procedures. We suggest using the anterior iliac crest when a large volume of cancellous bone is required.

Biologic approaches to the prevention of sexual transmission of human immunodeficiency virus

HIV prevention science has made progress, especially in Thailand and some sub-Saharan African countries. New cases of HIV in the United States, however, have not diminished and explosive epidemics in India and the People's Republic of China seem inevitable. Therefore, HIV prevention activities must move forward in parallel. Funding for biologic and behavioral research efforts must be balanced. Behavioral research must inform biologic strategies. In addition, HIV prevention efforts have been distorted by forces that require further consideration. First, the stigmatization associated with a diagnosis of HIV infection led to prevention efforts that virtually ignore the index case. Focusing entirely on the susceptible population puts intense and unrealistic pressure on behavior change and vaccine development. Although development of an HIV vaccine is desirable, there is no evidence that this goal can be achieved in the near future. Blind faith in vaccine technology detracts from pursuit of alternative aspects of prevention science. Vaccine development is but one of several key components to a broad-based prevention strategy. The history of control of infectious diseases has shown the need for targeting index cases. This certainly will prove important in HIV over the next few years. In developed countries, antiretroviral therapy for established HIV infection has become the standard of care. Increased knowledge of the biology of transmission of HIV suggests use of ART to prevent transmission. Such intervention must be accompanied by safer sex behavior in the index cases, and ultimately could lead to some form of monitoring and directly observed therapy. At this time, the latter approach seems unrealistic in developing countries, where the expense of drugs renders them unavailable. But there is every reason to believe that cheaper, more appropriate drugs will be developed before an effective vaccine. Furthermore, targeted use of ART might have disproportionate benefits in some countries. Women are the fastest growing HIV risk group. Several issues, both biologic and social, make this trend a concern. Increases in the number of HIV-infected women will lead to greater vertical transmission. Women possibly have different risk factors for acquisition and transmission than men. Information about the effects of vaginal ecology, specifically, the role of bacterial vaginosis, in the acquisition of HIV is essential because bacterial vaginosis can be reversed, at least transiently. To allow women to take an active role in HIV prevention methods, development of a topical microbicide is vital and may prove easier than a vaccine. Finally, HIV prevention efforts require knowledgeable, central leadership. All prevention efforts should be developed and implemented in parallel, to gain a synergistic result. Few vaccine experts are enthusiastic about microbicides, and HIV caregivers only rarely focus on the public health considerations of their patients. Stopping the spread of HIV requires a coordinated, concerted efforts using "all the tools in the toolbox."

Echocardiographic evaluation of the fetus with congenital cystic adenomatoid malformation

OBJECTIVES

The development of nonimmune hydrops is a known complication of congenital cystic adenomatoid malformation (CCAM) in the fetus. The aim of this study was to investigate the impact of CCAM on hemodynamics in the fetus and to determine whether cardiac dysfunction contributes to the development of hydrops in this patient population.

METHODS

The echocardiographic data from 41 consecutive fetuses diagnosed prenatally with CCAM were reviewed. The presence or absence of hydrops was noted in each patient. Two-dimensional ultrasonographic and Doppler data were compared between the two groups (with or without hydrops).

RESULTS

The mean gestational age for the study group at the time of imaging was 23.2 +/- 3.0 weeks. Hydrops was noted in 15 of 41 fetuses (36.5%). The fetuses that developed hydrops had a lower cardiac/thoracic ratio than those which did not develop hydrops (0.18 vs. 0.23, P = 0.001). The fetuses with hydrops also demonstrated an increase in early ventricular filling. The ratio of early ventricular filling to atrial contraction (E/A ratio) at both the tricuspid and mitral valves was significantly higher in the fetuses with hydrops (P = 0.005 and P = 0.03, respectively). Doppler interrogation of the inferior vena cava demonstrated a greater degree of reversal with atrial contraction in the hydrops group (29.7% vs. 15.1%, P = 0.003). The development of significant atrioventricular valve insufficiency was rare in the fetuses with hydrops (one of 15 cases).

CONCLUSIONS

Cystic adenomatoid malformation can result in significant cardiac compression in the fetus. This alters hemodynamics and may result in hydrops on the basis of elevated central venous pressure.

A data compression method for image time series

Image time series for functional studies frequently vary relatively little from one time point to the next. We describe here a method of lossless file compression that calculates the change in signal intensity as a char (one byte), as opposed to a short or long integer (usually two or four bytes), thus resulting in a compressed file size just over half the size of the original (a 2:1 compression ratio). The calculations and format are exceedingly simple; the compression time is comparable to the time required for a file copy, and is thus transparent to most users. The approach works equally well on any integer-based scanning modality, such as PET, CT, or DSA. Our purpose in this communication is to advocate it as a potential standard, to promote free interchange of scan data.

Acquiring simultaneous EEG and functional MRI

OBJECTIVE

Electroencephalography (EEG) is a challenge to record simultaneously with functional MRI (fMRI), for it is prone to large artifacts induced by both the static and the time-variant fields of the MR scanner. However, truly concurrent EEG/fMRI recording has great potential for clinical and scientific neurological applications. We have devised a method for acquiring EEG simultaneously with fMRI that minimizes contamination of the EEG signals.

METHODS

We recorded EEG differentially during fMRI using special twisted dual-lead electrodes in a bipolar montage, and a combination of analog pre-processing and digital post-processing of the EEG data. We implemented a functional scan protocol that typically yields artifact-free EEG over 87% of the MR scanning period.

RESULTS

Our approach greatly reduced gradient, radio frequency, motion and ballistocardiographic artifact in the EEG, and allowed continuous monitoring of the EEG during functional scanning. To illustrate the quality of the EEG following post-processing, we demonstrated that EEG recorded during fMRI retains useful spectral information.

CONCLUSIONS

Quality EEG may be recorded simultaneously with fMRI. With this union, activation maps could be made of any relevant changes in the EEG, such as inter-ictal spikes or spectral variations, or of evoked response potentials (ERPs).

Effects of genital tract inflammation on human immunodeficiency virus type 1 V3 populations in blood and semen

We have examined cell-free viral populations in the blood plasma and seminal plasma compartments of men infected with subtype C human immunodeficiency virus type 1 (HIV-1) using the V3-specific heteroduplex tracking assay (V3-HTA). We studied two cohorts of subjects who had visited either a sexually transmitted disease (STD) clinic for genital tract inflammation in the form of urethritis (n = 43) or a dermatology clinic (controls, n = 14) in Malawi. We have previously shown that the presence of urethritis is associated with an eightfold increase in virus load in the seminal plasma compartment (M. S. Cohen et al., Lancet 349:1868-1873, 1997). The purpose of this study was to determine whether genital tract inflammation and its treatment caused genetic instability in cell-free HIV-1 populations. In a cross-sectional analysis at study entry, three-fourths of the STD and control subjects had multiple V3 populations in their blood while 60% of the STD subjects and 79% of the control subjects had multiple V3 populations in their semen. Overall, one-fourth of all of the subjects showed discordance between results with blood and semen specimens when samples were compared for the presence and absence of subpopulations. When differences in the relative levels of abundance of bands were also taken into account, two-fifths of all of the subjects showed discordance between the compartments. Among the subset of subjects in whom multiple virus populations could be detected, half showed discordance between the compartments. There were no differences between STD and control cohorts for these comparisons of the compartments in this cross-sectional analysis at study entry. Longitudinal analysis of the viral populations from two separate clinic visits over 1 to 4 weeks showed that the complexity of each V3 population as measured by Shannon entropy was different in blood and semen at the two time points, indicating that the blood and semen constitute different compartments for HIV-1. The seminal plasma compartment was more dynamic than the blood plasma compartment for the STD subjects who were treated for urethritis, with changes being noted in the presence or absence of V3-HTA bands in the semen of 29% of these subjects but in the blood of only 9% of these subjects. However, the changes were generally small. Overall, our results suggest that 40% of male subjects show discordance between seminal and blood viral populations and that the complexity of each V3 population was different between the two compartments. Both of these results point to the partial independence of the seminal compartment as a viral niche within the body.

Breakthrough pneumococcal bacteremia in patients being treated with azithromycin and clarithromycin

Streptococcus pneumoniae strains have exhibited decreasing susceptibility to penicillins and macrolides during the past several years. We reviewed the medical charts of all patients with pneumococcal bacteremia who were admitted to a university hospital over a period of 1 year, to identify failures of outpatient therapy. Of 41 patients admitted with pneumococcal bacteremia, 4 had previously taken either azithromycin or clarithromycin for 3-5 days. All 4 had pneumococcal strains that exhibited low-level resistance to macrolide antibiotics. Among pneumococci, low-level resistance to macrolides can lead to clinical failure, and resistance to macrolides should be considered during the selection of empiric therapy for patients with presumed pneumococcal infections.

Patterns of brain activation in people at risk for Alzheimer's disease

BACKGROUND

The epsilon4 allele of the apolipoprotein E gene (APOE) is the chief known genetic risk factor for Alzheimer's disease, the most common cause of dementia late in life. To determine the relation between brain responses to tasks requiring memory and the genetic risk of Alzheimer's disease, we performed APOE genotyping and functional magnetic resonance imaging (MRI) of the brain in older persons with intact cognition.

METHODS

We studied 30 subjects (age, 47 to 82 years) who were neurologically normal, of whom 16 were carriers of the APOE epsilon4 allele and 14 were homozygous for the APOE epsilon3 allele. The mean age and level of education were similar in the two groups. Patterns of brain activation during functional MRI scanning were determined while subjects memorized and recalled unrelated pairs of words and while subjects rested between such periods. Memory was reassessed in 14 subjects two years later.

RESULTS

Both the magnitude and the extent of brain activation during memory-activation tasks in regions affected by Alzheimer's disease, including the left hippocampal, parietal, and prefrontal regions, were greater among the carriers of the APOE epsilon4 allele than among the carriers of the APOE epsilon3 allele. During periods of recall, the carriers of the APOE epsilon4 allele had a greater average increase in signal intensity in the hippocampal region (1.03 percent vs. 0.62 percent, P<0.001) and a greater mean (+/-SD) number of activated regions throughout the brain (15.9+/-6.2 vs. 9.4+/-5.5, P=0.005) than did carriers of the APOE epsilon3 allele. Longitudinal assessment after two years indicated that the degree of base-line brain activation correlated with degree of decline in memory.

CONCLUSIONS

Patterns of brain activation during tasks requiring memory differ depending on the genetic risk of Alzheimer's disease and may predict a subsequent decline in memory.

Rapid and effective correction of RF inhomogeneity for high field magnetic resonance imaging

The well-known variability in the distribution of high frequency electromagnetic fields in the human body causes problems in the analysis of structural information in high field magnetic resonance images. We describe a method of compensating for the purely intensity-based effects. In our simple and rapid correction algorithm, we first use statistical means to determine the background image noise level and the edges of the image features. We next populate all "noise" pixels with the mean signal intensity of the image features. These data are then smoothed by convolution with a gaussian filter using Fourier methods. Finally, the original data that are above the noise level are normalized to the smoothed images, thereby eliminating the lowest spatial frequencies in the final, corrected data. Processing of a 124 slice, 256 x 256 volume dataset requires under 70 sec on a laptop personal computer. Overall, the method is less prone to artifacts from edges or from sensitivity to absolute head position than are other correction techniques. Following intensity correction, the images demonstrated obvious qualitative improvement and, when subjected to automated segmentation tools, the accuracy of segmentation improved, in one example, from 35.3% to 84.7% correct, as compared to a manually-constructed gold standard.

Rapid and effective correction of RF inhomogeneity for high field magnetic resonance imaging

The well-known variability in the distribution of high frequency electromagnetic fields in the human body causes problems in the analysis of structural information in high field magnetic resonance images. We describe a method of compensating for the purely intensity-based effects. In our simple and rapid correction algorithm, we first use statistical means to determine the background image noise level and the edges of the image features. We next populate all "noise" pixels with the mean signal intensity of the image features. These data are then smoothed by convolution with a gaussian filter using Fourier methods. Finally, the original data that are above the noise level are normalized to the smoothed images, thereby eliminating the lowest spatial frequencies in the final, corrected data. Processing of a 124 slice, 256 x 256 volume dataset requires under 70 sec on a laptop personal computer. Overall, the method is less prone to artifacts from edges or from sensitivity to absolute head position than are other correction techniques. Following intensity correction, the images demonstrated obvious qualitative improvement and, when subjected to automated segmentation tools, the accuracy of segmentation improved, in one example, from 35.3% to 84.7% correct, as compared to a manually-constructed gold standard.

Spatiotopic organization in human superior colliculus observed with fMRI

Spatiotopy is a fundamental organizing principle of the visual brain. Using functional magnetic resonance imaging, we have demonstrated reliable data, consistent with spatiotopic organization in the human superior colliculi. Five subjects underwent cardiac-triggered echo-planar image acquisition, during which they viewed alternating left and right visual hemifield stimulation. Intensity variations from the variable TR were removed, and the data were evaluated for correlation with the lateralized stimulus. The data indicate a strongly preferential response of the left superior colliculus to the right side of visual space, and vice versa. This is consistent with previous findings in animal systems and confirms the existence of spatiotopy in the human superior colliculus.

Simultaneous determination of lamivudine and zidovudine concentrations in human seminal plasma using high-performance liquid chromatography and tandem mass spectrometry

A HPLC-MS-MS method was developed and validated to measure lamivudine and zidovudine simultaneously in small volumes of human seminal plasma. Sample preparation was simple and rapid, requiring 25 microl of sample, the use of isotopically labeled lamivudine and zidovudine as internal standards and ultrafiltration through a molecular mass cut-off membrane. Lamivudine and its internal standard were separated from zidovudine and its internal standard with isocratic HPLC. Detection was carried out using tandem mass spectrometry. This validated method was used to analyze seminal samples obtained from six HIV-positive patients prescribed lamivudine and zidovudine.

Trends of gonorrhea and chlamydial infection during 1985-1996 among active-duty soldiers at a United States Army installation

High rates of sexually transmitted diseases (STDs) have been reported in military populations. However, it remains uncertain whether the incidence of STDs is higher among military personnel than in the civilian population. The annual incidence of gonorrhea and chlamydia from 1985 through 1996 at Fort Bragg, North Carolina, was determined by use of a clinic database and demographic information for the entire installation. A direct standardization for age, sex, and race/ethnicity was performed, and the adjusted annual rates among active duty soldiers were compared with rates among men and women in North Carolina and the United States. Results showed that the adjusted incidence of gonorrhea and chlamydia among Fort Bragg soldiers remained higher overall than comparable state and national rates during the period of analyses. The 1996 adjusted chlamydia rates for male and female active duty soldiers were 3-fold to 6-fold higher than rates for males and females in North Carolina and in the United States as a whole. STDs continue to lead to significant morbidity in this representative military population.

Quantitation of human immunodeficiency virus type 1 RNA in different biological compartments

Little information is available describing viral loads in body fluids other than blood. In addition, the suitability of commercially available assays for human immunodeficiency virus type 1 (HIV-1) RNA quantitation has not been evaluated in most nonblood fluids. We compared Organon Teknika's nucleic acid sequence-based amplification method (NASBA) and Roche's Amplicor HIV-1 Monitor (reverse transcriptase PCR [RT-PCR]) for quantitating HIV-1 RNA in cerebrospinal fluid (CSF), saliva, breast milk, seminal plasma, and cervical-vaginal lavage fluid (CVL). Saliva and breast milk frequently demonstrated some inhibition in the RT-PCR assay, similar to the inhibition previously described in seminal plasma. Inhibition of the RT-PCR assay was not observed with CSF or CVL, nor in any of the NASBA assays. When fluids from HIV-infected individuals were tested by RT-PCR and NASBA, 73 and 27% of CSF samples and 60 and 40% of breast milk specimens had detectable RNA, respectively. These differences were not statistically significant. In cross-sectional studies using RT-PCR to measure viral RNA in paired blood plasma and CSF samples, 71% of blood plasma samples and 42% of CSF samples were positive. A similar analysis using NASBA with paired blood plasma and CVL, saliva, or seminal plasma samples revealed 91% were blood plasma positive and 55% were CVL positive, 76% were blood plasma positive and 46% were saliva positive, and 83% were blood plasma positive and 63% were seminal plasma positive. NASBA worked fairly well to quantitate HIV-1 RNA from all fluids without apparent inhibition. RT-PCR performed well on CVL and CSF, frequently with greater sensitivity, although its use in other fluids appears limited due to the presence of inhibitors. These studies demonstrate that viral loads in nonblood fluids were generally lower than in blood.

Features of urethritis in a cohort of male soldiers

Of 400 cases of urethritis in male soldiers enrolled in a behavioral intervention project, the etiology of 69% was defined at study enrollment, as well as the etiology of 72% of 25 repeated episodes involving 21 men during the first 78 days of active follow-up (5% of the cohort). Chlamydia trachomatis (36%), Neisseria gonorrhoeae (34%), and Ureaplasma urealyticum (19%) were the most common causes of infection identified at enrollment and during subsequent visits (44%, 28%, and 12%, respectively). By univariate analysis, patients with repeated infection ("repeaters") were significantly more likely to report a history of sexually transmitted disease (STD; relative risk [RR], 3) and sex with sex workers (RR, 4) than were nonrepeaters. By multivariate analysis, only STD history was significant (RR, 2.8). Characteristics of repeaters in this cohort suggest that specific patterns may be used to establish screening "profiles" of potential repeaters, by which such individuals might be targeted for aggressive intervention at the time of the initial diagnosis.