Growth failure as the first expression of malnutrition in children with human immunodeficiency virus infection.

BACKGROUND: To define the onset, pattern, and earliest manifestations of malnutrition related to HIV infection. METHODS: A retrospective cross-sectional analysis of changes in weight and growth in a group of 54 children with perinatally acquired HIV infection was conducted. Eight children had asymptomatic HIV infection, 26 had symptomatic infection, and 20 had symptomatic infection and were referred for nutritional support. RESULTS: We found an early decline in the rate of linear growth with a relative preservation of the weight-for-age. Weight-for-height measurements were preserved until there was advanced HIV-related disease. CONCLUSIONS: This pattern can result in a false impression of adequate nutrition and emphasizes the importance of longitudinal growth data of the child with HIV infection. Evidence of linear growth failure before clinical wasting is apparent is an absolute indication for aggressive nutritional support.

Acute hemiplegia associated with HIV infection.

An acute hemiplegia secondary to a large cerebral infarct is described in a 16-month-old infant with congenitally-acquired human immunodeficiency virus infection. Serial imaging studies during the next year documented improvement in his hemiplegia and a static underlying human immunodeficiency virus encephalopathy. Acquired immunodeficiency syndrome should be included in the differential diagnosis of children with acute hemiplegia.

Selection of temperature-sensitive mutants in persistent infection by parainfluenza virus type 3.

Vero cells persistently infected with parainfluenza virus type 3 (para 3) were examined for the production of temperature-sensitive (ts) mutants. After 6 months and 33 passages, ts mutants formed the great majority of the virus being shed into the supernatant fluid. Complementation studies gave evidence that the mutants shared a common lesion. Although ts mutants may play a role in the maintenance of persistent infection in this system, the mutants proved to be unstable when removed from the milieu of persistent infection. It is thus possible that their selection may be secondary to (an) unidentified factor(s) which play(s) a more primary role in the maintenance process.

Properties of temperature-sensitive mutants of parainfluenza virus type 3 selected during the course of persistent infection.

We investigated properties of the ts mutants that were selected during the course of persistent infection of Vero cells by parainfluenza virus type 3. The mutants demonstrated leakiness when infecting cells at high MOI and interfered with the growth of wild type virus, apparently by inhibiting a step prior to RNA synthesis.

Establishment of persistent infection by parainfluenza virus type 3: role of a syncytium inhibitor.

A strain of parainfluenza virus type 3 (para 3) that had undergone a series of undiluted passages failed to produce syncytia when inoculated on to Vero cells at a high m.o.i. The strain repeatedly produced stable persistent infections. Persistently infected cells were resistant to superinfection by homologous virus, showed the presence of virus-specific antigen and shed low quantities of infectious virus into the supernatant fluid. The undiluted passage parainfluenza virus type 3 strain produced a substance that inhibited syncytium formation by homologous virus and by measles virus but appeared to have no effect on virus replication. This inhibitor had no demonstrable effect on unrelated viruses, including some that produced syncytia. It had a mol. wt. between 3500 and 14000, was acid- and heat-labile, and was inactivated by anti-para 3 serum.

Tolerance in Staphylococcus aureaus: evidence for bacteriophage role.

The conversion of nontolerant Staphylococcus aureus to a tolerant organism is reported. It had been shown previously that a nontolerant strain produces tolerant progeny when it is incubated in media that contain a bacteria-free filtrate derived from cultures of each of the three tolerant stains of S. aureus. The tolerant progeny retain the characteristic tolerance upon serial subculture, and cell-free filtrates prepared from such subcultures are capable of converting nontolerant organisms to tolerant bacteria. A study of filtrates made from one of the tolerant strains revealed that all of the converting activity was sedimented by ultracentrifugation. DNase I and RNase A did not reduce the activity of the sediment, but Proteinase K completely diminished it. Equilibrium centrifugation of filtrates in cesium chloride showed that the conversion activity was maximal in the fraction with a density of approximately 1.445 +/- 0.015 g/ml. When a portion of this fraction was examined with the electron microscope, hexagonal bacteriophages (20 nm in diameter) were seen at this density. This observation seems to be evidence that a bacteriophage is involved in conversion of S. aureus from a nontolerant to a tolerant organism.

Demonstration of differences between strains of Staphylococcus aureus by peptidoglycan fingerprinting.

Lysis of peptidoglycans of Staphylococcus aureus yields products that exhibit strain-specific patterns on analysis by thin-layer chromatography and polyacrylamide gel electrophoresis. The patterns are demonstrated when products of the endogenous autolysins are examined and are enhanced and/or altered by the use of exogenous murolytic enzymes. These fingerprinting techniques were applied to the study of 55 strains of S. aureus. Twenty-six strains were from patients in five localized hospital outbreaks, and 29 were obtained randomly from individual patients. With only two exceptions all strains from a given outbreak had an identical murolytic pattern, whereas the random strains showed variable patterns. Peptidoglycan fingerprinting may be an adjunct tool for the hospital epidemiologist and may also be valuable for the study of certain biologic aspects of interstrain differences.

Mycobacterium chelonei infection of a Broviac catheter insertion site.

Mycobacterium chelonei infection developed at the insertion site of an indwelling Broviac catheter in a child with erythroleukemia. Direct adherence to and colonization of the intra- and extra-luminal surfaces of the catheter, with extension to the adjacent subcutaneous tissue, by this rapidly growing mycobacterium may have been the primary factor underscoring the infection. Nontuberculous mycobacteria such as Mycobacterium chelonei grow readily on routine bacteriologic media and resemble Corynebacterium spp. (diphtheroids) in their Gram staining and microscopic characteristics. The persistence of the infectious process and a diphtheroid-like microorganism despite antimicrobial therapy should raise the suspicion for a mycobacterial species.

Endotoxin levels in immunocompromised children with fever.

Febrile episodes for which no cause can be found are common in immunocompromised children. We postulated that circulating endotoxin, a known pyrogen, might be responsible for some of these episodes in the absence of documented infection. Plasma endotoxin levels were assayed using a recently developed Limulus amebocyte lysate assay enhanced in sensitivity and objectivity by the addition of a chromogenic substrate. Eighty-seven plasma endotoxin determinations were made in 36 immunocompromised children with fever. Convalescent endotoxin levels and levels in normal children were also obtained. It was concluded that a plasma endotoxin level of 35 pg (0.10 EU)/ml constitutes the upper limit of normal in children. Five children (14%) had elevated endotoxin levels in the course of the febrile episodes, in the absence of bacteremia or clinically diagnosed infection. In each case, the levels returned to normal during convalescence. It is concluded that endotoxemia is a possible cause or contributing cause of unexplained fever in immunocompromised children.

Reaction of Bacillus subtilis products with amebocyte lysates of the Japanese horseshoe crab, Tachypleus tridentatus.

Autoclaved aqueous extracts of Candida albicans cells (and the glucans isolated from them) give a positive reaction with a chromogenic substrate combined with amebocyte lysates of the Japanese horseshoe crab, Tachypleus tridentatus (CS-TAL). The extracts and glucans activate the lysate enzyme compound G, which in turn activates clotting enzyme. Activated clotting enzyme causes a positive CS-TAL reaction. C. albicans extracts and glucans react positively with a commercially available, unaltered CS-TAL preparation (Toxicolor), but they give a negative reaction with a CS-TAL from which compound G has been excluded (Endospecy). An autoclaved, sterile preparation of Sabouraud glucose broth used as a control in one experiment gave (like Candida extracts) a positive reaction with Toxicolor and a negative reaction with Endospecy. We found that the peptone powder used to make the Sabouraud glucose broth was contaminated with a strain of Bacillus subtilis. Autoclaved aqueous extracts of culture-grown B. subtilis cells were positive with Toxicolor and negative with Endospecy. This was also the case with two other strains of B. subtilis. Polysaccharides obtained from these extracts gave the same result. Endotoxin activates clotting enzyme through activation of the lysate enzyme compound C, which is present in both Toxicolor and Endospecy. Endotoxin, therefore, reacts with both CS-TAL preparations. Simultaneous assay with Toxicolor and Endospecy distinguishes endotoxin from fungal products, but since products of fungi and B. subtilis both give a positive Toxicolor and a negative Endospecy test, a simultaneous assay cannot differentiate them. However, this does not decrease the clinical value of the simultaneous Toxicolor-Endospecy assay for distinguishing fungal infection from endotoxemia because B. subtilis so rarely causes disease that it can be excluded from clinical consideration.

Reaction of fungal products with amebocyte lysates of the Japanese horseshoe crab, Tachypleus tridentatus.

A commercially available endotoxin assay (CS-TAL) employing a chromogenic peptide and an amebocyte lysate from the Japanese horseshoe crab, Tachypleus tridentatus, gave a positive result with aqueous extracts of all 15 strains of Candida albicans and 1 strain each of Candida tropicalis, Cryptococcus neoformans, and a Mucor species that we tested. Purified glucans prepared from the Candida strains gave the same results. Reconstruction experiments showed that the positive results were not due to contaminating endotoxin. By contrast, assays employing amebocyte lysates of the American horseshoe crab, Limulus polyphemus, were inconsistent. Japanese workers have presented evidence that glucans activate the Tachypleus amebocyte lysate system by acting on an enzyme different from that on which endotoxin acts. Using a Tachypleus lysate preparation (Endospecy; Seikagaku Kogyo, Tokyo, Japan) from which this enzyme was excluded, we demonstrated a 5- to 10-fold drop in reactivity to the aqueous Candida extracts and glucans, whereas reactivity to endotoxin was unchanged. Normal human plasma was shown to decrease the effect of fungal extracts on CS-TAL. This inhibition was completely removed by heating the plasma. Our results suggest that Tachypleus systems may be of use clinically in distinguishing bacterial from fungal infections.

Rapid detection of type A influenza viruses with monoclonal antibodies to the M protein (M1) by enzyme-linked immunosorbent assay and time-resolved fluoroimmunoassay.

Monoclonal antibodies (MAbs) to the M protein (M1) were used in the development of direct detection systems for type A influenza viruses in clinical specimens. Optimal detection by an enzyme-linked immunosorbent assay was achieved when MAbs were used as capture antibodies and rabbit polyclonal antibodies were used as sandwich antibodies. Detection by the enzyme-linked immunosorbent assay required amplification of the virus. direct detection in clinical specimens (nasopharyngeal aspirates) was accomplished when MAbs recognizing two distinct antigenic sites of M1 were used in a time-resolved fluoroimmunoassay. Type A influenza viruses could be detected equally well in specimens obtained during epidemics of both H3N2 and H1N1 influenza viruses.