Heterologous radioimmunossay of monkey alpha-fetoprotein.

Immunoelectrophoresis showed that rabbit anti-human alpha-fetoprotein (AFP) cross-reacts with monkey AFP which was not detectable in the serum from an adult non-pregnant monkey. A heterologous radioimmunoassay of monkey AFP was developed using this antiserum which circumvented the need for purified monkey AFP. The radioimmunoassay is of sufficient sensitivity to measure AFP in maternal and fetal serum and amniotic fluid in the rhesus monkey.     

Quantitative Studies on the Proliferation and Differentiation of Antibody-Forming Cells in Lymph

The transforming cells that appear in the efferent lymph from a lymph node responding to an antigenic challenge are part of a heterogeneous population which changes as the response progresses. Some cells containing small amounts of antibody appear early in the response and these cells have the cytologic characteristics of small and medium lymphocytes. They are, however, actively synthesizing DNA. As the immune response progresses, the antibody content of the cells in lymph increases. When incubated in vitro, cells in lymph appearing late in the response released 20 times more antibody per cell than those appearing early in the response. Large blast cells are the predominant antibody-forming cell in lymph. At the peak of a secondary challenge with horseradish peroxidase, up to 40% of the cells in lymph may be blast cells and, of these, two-thirds may contain specific antibody. It seems probable that most if not all of the blast cells responding to the antigen are involved directly in antibody and DNA synthesis. Cells in all stages of ultrastructural differentiation, and even mature plasma cells, were found to incorporate ³H-thymidine into their nuclear DNA.     

Recent changes among human influenza viruses

Recurrent epidemics of influenza are due to the frequent emergence of antigenic variants. With co-circulation of two influenza A subtypes and two antigenically distinct lineages of B viruses, genetic reassortment also has an important role in antigenic drift, as illustrated by recent changes in both A and B viruses. The H1N2 subtype viruses, which emerged during 2001, possessed a H1 HA similar to those of contemporary A/New Caledonia/20/99 (H1N1)-like viruses and seven genes closely related to those of recent H3N2 viruses, and did not represent a significant increase in the antigenic diversity of circulating viruses. The re-emergence of B/Victoria/2/87-lineage viruses, previously prevalent during the 1980s, in 2000 has been followed by the predominant circulation of reassortant B viruses possessing a B/Victoria-lineage HA and a B/Yamagata-lineage NA similar in sequence to those of recent B/Sichuan/379/99-like viruses. These events emphasize not only the lack of divergence in the complementary functional characteristics of the HA and NA of divergent influenza B lineages, but also the apparent convergence in compatibility between the H1 and N2 components of the two influenza A subtypes.     

Nucleotide sequence of the coat protein gene of a necrotic strain of potato virus Y from New Zealand

Summary The sequence of the 3-terminal 1,134 nucleotides of the genome of a New Zealand isolate of a necrotic strain of potato virus Y (PVY^N) has been determined. This sequence contains one large open reading frame of 796 nucleotides, the start of which was not identified, which is capable of encoding a protein of 264 amino acid residues with a molecular weight of 29,631. Comparison of the amino acid sequence with a published coat protein sequence of another strain, PVY-D, and with the amino acid sequence deduced from PeMV cDNA sequence data, confirms that the 3 cistron encodes the viral coat protein in PVY^N. Adjacent to the 3 end of the coding region there is an untranslatable sequence of 326 nucleotides terminating in a polyadenylate tract. An alignment of the PVY^N amino acid sequence with the coat protein sequences of six other potyviruses revealed significant sequence similarities in the internal and carboxy terminal regions. Much amino acid sequence similarity was found between PVY^N, PVY-D, and PeMV (91–93%), suggesting that PeMV should be regarded as a PVY strain. An analysis of the 3-untranslated region of the six potyviruses revealed PVY^N and PeMV as the only viruses displaying sequence similarity in this region. The 3-untranslated sequences of PVY^N and PeMV were further examined for secondary structure.     

Characterization of virus-specific messenger RNAs from avian fibroblasts infected with fowl plague virus

In cell-free protein synthesizing systems from wheat embryos, messenger RNAs extracted from chick embryo fibroblasts infected with fowl plague virus direct the synthesis of nine virus-specific polypeptides, two of which may be related to the virus-specific glycopolypeptides. All of the mRNAs are complementary in sequence to virion RNA, and RNAs which do not contain poly A appear to be translated as efficiently as their polyadenylated counterparts. Under certain conditions of incubation, virion RNA also directs the synthesis of discrete polypeptides but these products are not detected in infected cells.     

Emergence of influenza A H1N2 reassortant viruses in the human population during 2001

A recombinant vaccinia virus encoding rotavirus protein NSP3 driven by an internal ribosome entry site (IRES) from the encephalomyocarditis (EMC) virus was able to abate protein synthesis in BSC1 cells by 25-fold, with as much as 30% of the remaining protein synthesis being NSP3. Hence NSP3 shuts off host cell protein synthesis down to the level seen during rotavirus infection but is unable to prevent translation from EMC IRES-driven genes. This effect was abolished by deletions in the eIF4G-binding (aa 274-313) and the dimerization (aa 150-206) but not the viral mRNA-binding (aa 83-149) domains, supporting that NSP3 functions in vivo as a dimer. Binding of eIF4G by NSP3 has been implicated in interfering with mRNA 5'-3' circularization, hence such circularization is essential for translation in mammalian cells.     

Maturation of the proximal tubule in the puppy kidney: a comparison to the adult

Two- to four-day-old beagle puppy kidneys were preapred for transmission and scanning electron microscopy and compared to similarly prepared adult tissues. Proximal tubules of puppy kidneys which contained nephrons in various stages of differentiation were examined and maturational changes were described. Lateral surface contours of proximal tubular cells were initially smooth and relatively unfolded, but progressively acquired complex processes that may be recognized as lateral ridges and lateral-basal processes. Basal projections began as short, stubby processes and gradually took on either a narrow, plate-like or finger-like appearance. Mitochondria lysosomes and apical vacuoles increased in number as the tubules matured. Mitochondria lacked orientation in outer cortical tubules, but exhibited some vertical arrangement within basal processes in inner cortical tubules. Despite features indicating advanced maturation of tubules in the inner cortex, puppy kidneys lacked the lipid droplets characteristic of the adult. Thus, differentiation of this portion of the developing nephron into S1, S2 and S3 segments was not possible at day 4. Morphometric analyses of the lateral and basal membrane surface concentration of proximal convulted tubules from the puppy revealed all cells to have a significantly smaller membrane area than that of the adult. However, the inner cortical cells of the puppy had a greater surface concentration than those of the outer cortex. The reduced transport capacity of the puppy proximal tubule may be realted to the lack of segmentation and/or reduced lateral-basal surface area.     

Associations between Mycoplasma genitalium,Chlamydia trachomatis and pelvic inflammatory disease

OBJECTIVE: To evaluate the association between Mycoplasma genitalium, Chlamydia trachomatis, and pelvic inflammatory disease (PID) METHODS: A case-control methodology was used. Swab eluates were processed using the QIAamp DNA mini kit. Polymerase chain reaction (PCR) for M genitalium was carried out using a real time in-house 16S based assay. An endocervical swab was taken and tested for the presence of C trachomatis (ligase chain reaction, Abbott Laboratories), and a high vaginal swab was taken and tested for the presence of Neisseria gonorrhoeae and bacterial vaginosis. RESULTS: Of the PID cases 13% (6/45) had evidence of M genitalium infection compared to none of the controls (0/37); 27% (12/45) of the cases had C trachomatis infection compared to none of the controls; and 16% (7/45) of cases only had serological evidence of C trachomatis infection compared to 5% (2/37) of controls. Cases were more likely to present with M genitalium and/or C trachomatis than controls (p<0.001). CONCLUSIONS: This study indicates that there may be an association between M genitalium and PID, and that this relation is largely independent of C trachomatis. Future studies need to investigate the pathological basis of the relation between M genitalium and PID using samples from women with PID diagnosed using laparoscopy and endometrial biopsy. Little is known about the epidemiology of M genitalium: large scale epidemiological investigations are needed to determine the prevalence, incidence, and factors associated with this emerging infection.     

Shunt surgery for treatment of portal hypertension in children

Shunt surgery in children suffering from portal hypertension (PH) is considered as an immediate and definite mode of prevention of recurrent gastrointestinal hemorrhage. Certain conditions must be met: (a) normal liver; (b) normal veins available within the portal system; (c) a sufficient portosystemic gradient of pressure; and (d) a surgical team with experience in portal venous surgery. In patients in whom PH is an epiphenomenon of severe liver disease, other means of hemostasis for bleeding esophageal varices should be sought. The difficult decision is in the child with specific liver alterations without major hepatocellular dysfunction but in whom the prognosis cannot be precisely foreseen. A few more years will be needed before one can tell if shunt surgery is the best choice for this category of patient.

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Resumen La cirugía derivativa (shunts portosistémicos) en los niños que sufren de hipertensión portal es considerada como una forma inmediata y definitiva de prevenir la hemorragia gastrointestinal recurrente. Ciertas condiciones deben existir para su realization: (a) hígado normal; (b) venas disponibles dentro del sistema porta; (c) suficiente gradiente en las presiones portosistémicas; y (d) disponibilidad de un equipo quirúrgico con experiencia en cirugía venosa portal. Otros medios de hemostasis de las várices esofágicas sangrantes deben ser utilizados en aquellos pacientes en quienes la hipertensión portal es un epifenómeno de enfermedad hepática severa. La decisión más difícil se presenta en el niño con alteraciones hepáticas específicas pero sin mayor disfunción hepatocelular en quien no se puede determinar con precisión el pronóstico. Todavía serán necesarios unos años más antes de poder afirmar que la cirugía derivativa representa la mejor escogencia para esta categoría de pacientes.

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Résumé La dérivation portale chez les enfants atteints d'hypertension portale constitue une méthode immédiate et définitive de prévention des hémorragies digestives récidivantes. Les conditions les plus favorables sont les suivantes: a) foie normal; b) veines disponibles dans le secteur porte pour l'anastomose; c) gradient de pression suffisant entre le système porte et le système cave et d) équipe entraînée à la chirurgie portale. Lorsque l'hypertension portale est un épiphénomène au cours d'une affection hépatique sévère, d'autres méthodes d'hémostase des varices oesophagiennes rompues doivent être envisagées. La décision du choix thérapeutique à adopter est difficile lorsqu'il existe une atteinte hépatique, sans altération hépatocellulaire majeure, mais de pronostic incertain à long terme. Quelques années encore seront nécessaires avant de pouvoir affirmer que la dérivation représente la meilleure opération pour traiter ce type d'hypertension portale.