The detection of HIV-1 proviral DNA by PCR in clotted blood specimens

Six hundred and ninety-two specimens, each consisting of a suspension of the residual free cells in samples of clotted blood (but not the clots themselves) from 680 patients at high risk for exposure to human immunodeficiency virus (HIV), were tested by a nested polymerase chain reaction (PCR) procedure which had been optimized to give a sensitivity of detection of one copy of HIV-1 proviral plasmid DNA, and the results were compared to those of testing for antibody to HIV on the same specimens. Fifty-one of the specimens were positive for antibody to HIV and 49 of these were also positive by the PCR; the two samples which gave discordant results were found to be PCR-positive when the test was repeated on DNA extracted from the clots themselves. Two specimens were found to be negative for antibody to HIV but were positive by the PCR (53 positive specimens in all). Direct sequencing of the PCR DNA products confirmed their specificity in all cases and demonstrated that no two patients gave the same predicted amino acid sequence for the V3 loop region. The sequences revealed both European/North American and African motifs at the crown of the V3 loop thus indicating a diversity of HIV strains in the SW Thames Region of South London. The results show that the confirmatory PCR for HIV-1 can be carried out efficiently on the same clotted blood specimens as used for routine HIV serology on patients undergoing diagnostic evaluation.

A review and update on adult syphilis, with particular reference to its treatment

Syphilis has become less common in Europe in the last decade, but has once again become a major problem in the USA, and remains so in many developing countries. Several treponemal genes have now been cloned and expressed in Escherichia coli, allowing study of treponemal proteins. The importance of cell mediated immunity in syphilis has been demonstrated in animal models. A diagnosis of syphilis is usually confirmed by dark-field microscopy or serological tests. Seroconversion may be delayed in HIV infected individuals. A positive reaginic test in cerebrospinal fluid (CSF) has a high specificity but low sensitivity in the diagnosis of neurosyphilis. Indeed, virulent treponemes can be identified in CSF samples which have negative reaginic tests, normal cell counts and protein levels. In the CSF, the FTA-Abs test has a high sensitivity but low specificity for neurosyphilis. Penicillin remains the treatment of choice for all stages of syphilis, although it penetrates the blood brain barrier poorly. Treatment with intramuscular benzathine penicillin 2.4 million units stat, or 600,000 units procaine penicillin daily does not produce treponemicidal levels within the CSF. However, the incidence of neurosyphilis is low in immunocompetent patients treated with such regimens during early syphilis. Acceptable alternatives in penicillin-allergic patients include ceftriaxone and doxycycline. Erythromycin is not recommended as it has produced unacceptably high rates of treatment failure. Recently, a strain of macrolide-resistant Treponema pallidum was isolated from a patient with secondary syphilis. For the treatment of neurosyphilis, treponemicidal levels of penicillin can be achieved in the CSF using 2.4 million units procaine penicillin daily with concurrent probenecid 500 mg 4 times a day, or an intravenous infusion of benzyl penicillin 12-24 million units daily. Early syphilis can be treated adequately over 10 days, but 21 to 28 days is appropriate for late syphilis. In HIV-infected patients syphilis may present atypically with initially negative serological tests. Treatment of early syphilis in HIV-positive patients has been associated with the early development of neurosyphilis. It is advisable to treat all patients co-infected with HIV with an antibiotic regimen that achieves adequate levels within the CSF.

Treatment of obsessive-compulsive disorder by psychosurgery

We report a longitudinal study of 26 patients with medically intractable obsessive-compulsive disorder (OCD) who were treated with psychosurgery and had a comprehensive follow-up for a mean 10 years. Seventeen patients had combined orbitomedial and cingulate lesions, 6 cingulate lesions only and 3 orbitomedial lesions only. Eighteen patients were interviewed personally and lesions verified on magnetic resonance imaging scans in fourteen. On a 6-point global rating scale, 10 (38%) patients had obvious improvement, another 6 (23%) showed mild improvement of doubtful clinical value, and the remaining 10 showed either no change (n = 6; 23%) or were judged to be worse (n = 4; 15%). Both obsessive and compulsive symptoms improved, and this change was independent of the changes in anxiety and depression scores. No significant predictors of improvement were identified. Patients with cingulate lesions only fared worse. Eight patients who had a second operation did not show much improvement. A comparison of a subgroup of patients with 10 matched nonsurgical OCD controls supported the contention that the improvement in OCD was attributable to the psychosurgery. Important adverse effects in the stereotactic surgery group (n = 20) were epilepsy (1 patient) and personality change (2 patients). The psychosurgery group performed relatively poorly on the Wisconsin Card Sort Test but did not show any deterioration in Wechsler Intelligence and Memory scores.

Optic neuropathy in Paget's disease

Of 22 patients (18 men and four women ranging in age from 50 to 89 years) with radiographic and clinical evidence of Paget's disease, nine had visual field defects. All nine had arcuate scotomas and five of the nine had generalized constriction. The visual field changes were asymptomatic in six of nine patients and progressive in two patients. Only two patients had radiographic evidence of optic canal constriction by bony impingement. There was no objective improvement in the optic neuropathy in the three patients treated with synthetic salmon calcitonin. Our data suggested that the optic neuropathy of Paget's disease cannot be explained solely on the basis of bony compression and the cause of optic neuropathy in patients with normal optic canals remains unknown.

The significance of disc hemorrhage in open-angle glaucoma

Thirty eyes of 25 patients with open-angle glaucoma and disc splinter hemorrhage (20 with unilateral and five with bilateral hemorrhage) were studied as to the extent of the visual field loss in relation to the time of onset and location of the disc hemorrhage. The degree of visual field deterioration over a follow-up period of one month to seven years was found to be higher in eyes with disc hemorrhage when compared to the contralateral eyes without disc hemorrhage of patients with bilateral open angle glaucoma.