Genital reinfection after recovery from initial genital infection with herpes simplex virus type 2 in guinea pigs

The natural history of genital reinfection with herpes simplex virus type 2 (HSV-2) three weeks to one year after initial infection was explored by using a guinea pig model. Intravaginal reinoculation with HSV-2 of animals that had recovered from initial genital infection produced by wild-type or thymidine kinase-deficient HSV-2 produced asymptomatic genital reinfection characterized by high-titered replication of HSV-2 in the vaginal vault. Reinoculation did not result in acute neural infection, as was seen during initial genital herpes, and no evidence of latent infection by the rechallenge strain could be demonstrated. The frequency of recurrences appeared to be established by the initial infection because reinfection did not alter the pattern of recurrent genital herpes. The present study suggest that asymptomatic reinfection may produce a reservoir of communicable virus and that initial infection with a less virulent mutant of HSV-2 may provide protection against subsequent reexposure to wild-type HSV-2.     

Pretreatment hematocrit as an independent prognostic variable in Hodgkin's disease

Pretreatment hematocrit in 117 advanced-stage Hodgkin's disease patients treated with a combined modality therapy program was evaluated as an independent prognostic variable with regard to survival and relapse-free survival. Age greater than 40 years, and multiple extranodal sites of involvement were found to be statistically significant independent negative prognostic factors with regard to survival. Pretreatment hematocrit, however, was not an independent negative prognostic variable.     

Antibody to herpes simplex virus (HSV) ICP-35 proteins after HSV challenge of animals immunized with HSV subunit vaccines

The serological response to the ICP-35 group of herpes simplex virus type 2 (HSV-2) proteins was examined 30 d after vaginal challenge with HSV-2 of guinea pigs previously immunized with HSV glycoproteins. Detection of antibodies to ICP-35 proteins correlated best with the magnitude of vaginal viral replication. Animals that developed antibody to ICP-35 proteins had more-frequent recurrences (P less than .0002) that were of longer duration (P less than .005) than animals that did not. By covariate analysis the number of recurrences appeared to be related to the severity of the acute disease, inversely related to the enzyme-linked immunosorbent assay titer of antibody to HSV glycoproteins, and related to the detection of antibody to ICP-35 proteins. The duration of recurrent disease, however, could only be correlated with the presence of antibody to ICP-35 proteins. Detection of antibody to ICP-35 proteins is thus a useful prognostic indicator for identifying animals that developed more-severe recurrent disease.     

New England Medical Center Posterior Circulation Stroke Registry: I. Methods, Data Base, Distribution of Brain Lesions, Stroke Mechanisms, and Outcomes

Among 407 New England Medical Center Posterior Circulation Registry (NEMC-PCR) patients, 59% had strokes without transient ischemic attacks (TIAs), 24% had TIAs before strokes, and 16% had only posterior circulation TIAs. Embolism was the commonest stroke mechanism accounting for 40% of cases (24% cardiac origin, 14% arterial origin, 2% had potential cardiac and arterial sources). In 32%, large artery occlusive lesions caused hemodynamic brain infarction. Stroke mechanisms in the posterior and anterior circulation are very similar. Infarcts most often included the distal posterior circulation territory (rostral brainstem, superior cerebellum and occipital and temporal lobes), while the proximal (medulla and posterior inferior cerebellum) and middle (pons and anterior inferior cerebellum) territories were equally involved. Infarcts that included the distal territory were twice as common as those that included the proximal or middle territories. Most distal territory infarcts were attributable to embolism. Thirty day mortality was low (3.6%). Embolic stroke mechanism, distal territory location, and basilar artery occlusive disease conveyed the worst prognosis.     

Digital and conventional chest images: observer performance with Film Digital Radiography System

The Film Digital Radiography System (FilmDRS) is a device with a laser optical film digitizer, 2,000 X 2,000 X 12-bit memory, and a 1,000-line video display. To evaluate the adequacy of this device for general radiography of the chest, four readers independently analyzed both radiographs and the corresponding video display of the digitized chest images of 150 patients, consisting of 100 images of abnormalities and 50 normal images. The overall results indicate equal sensitivity for the two systems. The FilmDRS, with interactive windowing, proved superior in the detection of hilar and mediastinal disease. X-ray film was superior in allowing detection of hyperlucent states. There was equivalent sensitivity for other disease categories. Superior specificity was achieved with conventional radiographs.     

New England Medical Center Posterior Circulation Stroke Registry II. Vascular Lesions

Among 407 New England Medical Center Posterior Circulation Registry (NEMC-PCR) patients, the extracranial (ECVA) and intracranial vertebral arteries (ICVA) were the commonest sites of severe occlusive disease followed by the basilar artery (BA). Severe occlusive lesions were found in >1 large artery in 148 patients; 134 had unilateral or bilateral severe disease at one arterial location. Single arterial site occlusive disease occurred most often in the ECVA (52 patients, 15 bilateral) followed by the ICVA (40 patients, 12 bilateral) and the BA (46 patients). Involvement of the ICVAs and the BA was very common and some patients also had ECVA lesions. Hypertension, smoking, and coronary and peripheral vascular disease were most prevalent in patients with extracranial disease while diabetes and hyperlipidemia were more common when occlusive lesions were only intracranial. Intra-arterial embolism was the most common mechanism of brain infarction in patients with ECVA and ICVA occlusive disease. ICVA occlusive lesions infrequently caused infarction limited to the proximal territory (medulla and posterior inferior cerebellum). BA lesions most often caused infarcts limited to the middle posterior circulation territory (pons and anterior inferior cerebellum). Posterior cerebral artery occlusive lesions were predominantly embolic. Penetrating artery disease caused mostly pontine and thalamic infarcts. Prognosis was poorest in patients with BA disease. The best prognosis surprisingly was in patients who had multiple arterial occlusive lesions; they often had position-sensitive transient ischemic attacks during months or years.