Regulation of Epstein-Barr virus infection by recombinant interferons. Selected sensitivity to interferon-gamma

Interferons (IFN) are antiviral proteins that may be important in mediating cellular defenses against Epstein-Barr virus (EBV) infection. However, the means by which IFN-alpha, -beta and -gamma modify EBV infectivity are not clear. We have evaluated the effects of purified recombinant preparations of all three classes of IFN on EBV-induced B lymphocyte proliferation and Ig secretion. When added early after EBV infection, all three recombinant IFN reduced B cell outgrowth and Ig secretion. IFN-gamma exerted a 7-10-fold more potent antiviral effect than IFN-alpha or -beta. All three types of IFN act directly on B cells. Monocytes and natural killer cells are not necessary for the anti-EBV activity. Of the three recombinant IFN, only IFN-gamma reduced EBV-induced proliferation and Ig secretion when added 3-4 days after virus infection; IFN-alpha/beta were only effective up to 24 h. B lymphoblastoid lines already transformed by EBV are insensitive to the anti-proliferative actions of all three types of IFN. On the basis of these findings, we propose three phases of regulation during EBV infection. In the early phase, EBV-infected cells can be regulated by all IFN. Subsequently, there is an intermediate period where only IFN-gamma is capable of directly affecting EBV-induced B cell responses. In the third phase, B lymphocytes become insensitive to direct actions of all IFN and are now subject to regulation only by cytotoxic cells.     

Norepinephrine-induced cardiac hypertrophy of the cat heart.

Norepinephrine administration causes progressive hypertrophy of the mammalian heart as measured by myocardial mass. The purpose of this study was to determine the growth response of the myocardial tissue components as well as the myocardial cell itself to norepinephrine. Young, adult cats were given low doses of norepinephrine in dextrose or dextrose alone twice daily for 15 days. On day 16, there were no changes in the animals body weight, right ventricular systolic pressure, right ventricular end-diastolic pressure, heart rate, cardiac index, or blood pressure. However, the right ventricle/body weight, the left ventricle/body weight and the total heart weight/body weight were increased significantly in the norepinephrine treated animals. The increase was on the order of 40%. The cardiac muscle cell was also significantly increased in size and both the right and left ventricular cardiac muscle cells exhibited a dramatic increase in size as measured by cross sectional area. Upon stereological examination it was found that the amount of hypertrophy as seen in the cardiac muscle cells was paralleled by the hypertrophy seen in the other tissue components of the myocardium. The volume density of the muscle cells, the interstitial components, as well as the blood vessel compartment were identical in the control and in the norepinephrine-treated groups. In conclusion, this study demonstrates that the response of the myocardium to norepinephrine is similar to that seen in response to a volume overload rather than that seen in response to pressure overload.     

Central and peripheral mediation of human force sensation following eccentric or concentric contractions

Fatigue was induced in the triceps brachii of the experimental arm by a regimen of either eccentric or concentric muscle actions. Estimates of force were assessed using a contralateral limb-matching procedure, in which target force levels (25 %, 50 % or 75 % of maximum) were defined by the unfatigued control arm. Maximum isometric force-generating capacity was reduced by 31 % immediately following eccentric contractions, and remained depressed at 24 (25 %) and 48 h (13 %) post-exercise. A less marked reduction (8.3 %) was observed immediately following concentric contractions. Those participants who performed prior eccentric contractions, consistently (at all force levels), and persistently (throughout the recovery period), overestimated the level of force applied by the experimental arm. In other words, they believed that they were generating more force than they actually achieved. When the forces applied by the experimental and the control arm, were each expressed as a proportion of the maximum force that could be attained at that time, the estimates matched extremely closely. This outcome is that which would be expected if the estimates of force were based on a sense of effort. Following eccentric exercise, the amplitude of the EMG activity recorded from the experimental arm was substantially greater than that recorded from the control arm. Cortically evoked potentials recorded from the triceps brachii (and extensor carpi radialis) of the experimental arm were also substantially larger than those elicited prior to exercise. The sense of effort was evidently not based upon a corollary of the central motor command. Rather, the relationship between the sense of effort and the motor command appears to have been altered as a result of the fatiguing eccentric contractions. It is proposed that the sense of effort is associated with activity in neural centres upstream of the motor cortex.     

Facio-cardio-renal (Eastman-Bixler) syndrome

We report on a 5-year-old boy with moderate mental retardation, horseshoe kidneys, tricuspid valve prolapse, and a characteristic face with broad nasal root, prominent ears, and a cleft palate. These manifestations suggested the diagnosis of the Eastman-Bixler syndrome. Our patient also had an isolated growth hormone deficiency which responded successfully to treatment.     

Hepatitis E virus infection in chimpanzees: a retrospective analysis

Summary.  Different patterns of disease were observed among 11 chimpanzees who were inoculated intravenously with hepatitis E virus (HEV) positive fecal specimens from four different outbreaks (Nepal 1981, Uzbekistan 1981, Pakistan 1985, and Mexico 1986). Five chimpanzees had marginal or no liver enzyme elevations within 70 days of inoculation. Two of the chimpanzees had limited viremia, but did not produce detectable antibody. The four remaining chimpanzees had liver enzyme elevations, viral shedding, viremia, seroconversion to anti-HEV, and detectable HEV antigen in liver biopsy specimens. These results may reflect the range of infection patterns that develop in humans after natural exposure to the HEV. Received December 29, 1999/Accepted February 21, 2000     

Giant lymph-node hyperplasia, plasma-cell type, of the mediastinum, with peripheral neuropathy.

A case of mediastinal giant lymph-node hyperplasia, plasma-cell type, is described. The patient had progressive peripheral neuropathy for which no apparent cause was found. Giant lymph-node hyperplasia with associated peripheral neuropathy has not been reported previously.     

Multiple cerebral metastases: detectability with Gd-DTPA-enhanced MR imaging

Sixteen patients with suspected cerebral metastases were studied with magnetic resonance (MR) imaging before and after the intravenous administration of 0.1 mmol/kg of gadolinium diethylenetriaminepenta-acetic acid. The images were interpreted blindly by two neuroradiologists; all clinical, radiologic (computed tomographic and MR imaging), and pathologic data were reviewed to arrive at a final "best diagnosis," which was then compared with the prior blinded interpretations. Of seven patients found to have multiple metastases, six (86%) had at least one tumor nodule depicted by postinfusion MR imaging that was missed by one or both observers on review of preinfusion images alone. Lesions missed on preinfusion studies were usually small nodules hidden by or not detected next to regions of high-signal edema thought to be related to the adjacent tumor nodule. The authors believe that contrast enhancement improves detection of metastatic foci with MR imaging and that the findings indicate broader implications for the detection of multiple lesions from other causes.     

A Randomized Pilot Study of DASH Patterned Groceries on Serum Urate in Individuals with Gout

The Dietary Approaches to Stop Hypertension (DASH) diet reduces serum urate (SU); however, the impact of the DASH diet has not been previously evaluated among patients with gout. We conducted a randomized, controlled, crossover pilot study to test the effects of ~$105/week ($15/day) of dietitian-directed groceries (DDG), patterned after the DASH diet, on SU, compared with self-directed grocery shopping (SDG). Participants had gout and were not taking urate lowering therapy. Each intervention period lasted 4 weeks; crossover occurred without a washout period. The primary endpoint was SU. Compliance was assessed by end-of-period fasting spot urine potassium and sodium measurements and self-reported consumption of daily servings of fruit and vegetables. We randomized 43 participants (19% women, 49% black, mean age 59 years) with 100% follow-up. Mean baseline SU was 8.1 mg/dL (SD, 0.8). During Period 1, DDG lowered SU by 0.55 mg/dL (95% CI: 0.07, 1.04) compared to SDG by 0.0 mg/dL (95% CI: −0.44, 0.44). However, after crossover (Period 2), the SU difference between groups was the opposite: SDG reduced SU by −0.48 mg/dL (95% CI: −0.98, 0.01) compared to DDG by −0.05 mg/dL (95% CI: −0.48, 0.38; P for interaction by period = 0.11). Nevertheless, DDG improved self-reported intake of fruit and vegetables (3.1 servings/day; 95% CI: 1.5, 4.8) and significantly reduced total spot urine sodium excretion by 22 percentage points (95% CI: −34.0, −8.6). Though relatively small in scale, this pilot study suggests that dietitian-directed, DASH-patterned groceries may lower SU among gout patients not on urate-lowering drugs. However, behavior intervention crossover trials without a washout period are likely vulnerable to strong carryover effects. Definitive evaluation of the DASH diet as a treatment for gout will require a controlled feeding trial, ideally with a parallel-design.