肩、肘关节外科新进展

肩关节（Shoulder） 旋转袖（Rotator Cuff） 基础研究（Basic Science） Zuckerman讨论了软骨诱导形态发生蛋白-2（cartilagederived morphogenetic protein-2，CDMP-2）的早期工作。在鼠肌腱修复中，4周时CDMP-2治疗组的修复强度高于未治疗组。Dines讨论了关于血小板衍生生长因子（platelet—derived growth factor，PDGF）和胰岛素样生长因子-1（insulin-like growth factor-1，IGF-1）最初的研究观察。     

7-甲氧基-4′-羟基-3′-二乙胺甲基异黄酮(MHDF)对大鼠血流动力学和主动脉的作用

本实验观察了MHDF对整体大鼠血流动力学和离体大鼠胸主动脉的作用。结果表明iv MHDF(3～12.8 mg/kg)能降低大鼠左心室±dp/dt_max,V_max,V_pm和LVSP,延长T-dp/dt_max,减慢心率。MHDF还能舒张大鼠胸主动脉,ED₅₀为6.5×10^-6mol/L;非竞争拮抗NA和CaCl₂致主脉收缩,pD₂′为3.11±0.21和3.73±0.07;抑制高K⁺致主动脉收缩,IC₅₀为1.76×10^-5mol/L。提示MHDF对血管的作用与α受体阻断剂不同,而可能与钙拮抗有关。     

The Oxford Optical Pointer: a direction-sensing device with proportional electrical output

For some disabled people pointing provides a more convenient means of communication and control than the use of switches. The quadriplegic who retains good control of head movement can be provided with a number of input alternatives, but no existing system meets all the requirements of a general-purpose electronic pointing device. Consequently the Oxford Optical Pointer has been developed. The principle by which it converts relative direction into analogue electrical signals is described and its application as a head-mounted device for controlling an electric wheelchair is presented.     

Safest birth attendants: recent Dutch evidence.

Analysis of national perinatal statistics from Holland, 1986, demonstrates that for all births after 32 weeks' gestation mortality is much lower under the non-interventionist care of midwives than under the interventionist management of obstetricians at all levels of predicted risk. This finding confirms with great authority the conclusions of all earlier impartial analyses from Britain and other countries which agree in contradicting the claims on which the organisation of maternity services in most developed countries is now based, namely, that childbirth is made so much safer by the application of high technology that only this option should be provided.     

Follicular dendritic cells (FDC) in retroviral infection: host/pathogen perspectives

Summary: Follicular dendritic cells (FDC) are found in the follicles of virtually all secondary lymphoid tissues. In health, these cells trap and retain antigens (Ag) in the form of immune complexes and preserve them for months in their native conformation. FDC thus serve as a long-term repository of extracellular Ag important for induction and maintenance of memory responses. In retroviral infection. FDC trap and retain large numbers of retroviral particles with profound effects on FDC. FDC-trapped retrovirus induces follicular hyperplasia, and conventional Ag trapped prior to infection are lost and new Ag cannot be trapped. Concomitantly, antibody-forming cells (AFC) specific for Ag lost from FDC decrease follow I by loss of specific serum antibody (Ab). Eventually, FDC die and follicular lysis occurs. From the pathogen perspective, binding to FDC is remarkably beneficial, bringing together virus and activated target cells that are highly susceptible to infection. Furthermore, FDC permit HIV to infect surrounding cells even in the presence of a vast excess of neutralizing Ab. Preliminary data suggest that FDC maintain virus infectivity - even when the virus cannot replicate. Thus retrovirus infection monopolizes FDC networks, thereby transforming the FDC Ag repository into a highly infectious retroviral reservoir.     

Place of birth and perinatal mortality

Analyses of the published results of national surveys and specific studies, as well as of the official stillbirth statistics, consistently point to the conclusion that perinatal mortality is significantly higher in consultant obstetric hospitals than in general practitioner maternity units or at home, even after allowance has been made for the greater proportion of births in hospital at high pre-delivery risk. Unpubliched results of the British births 1970 survey, which have now become available, make possible a direct and authoritative analysis of data on the safest place of birth. Not only does this make the earlier conclusion more certain, but it confounds the doctrine that obstetric intranatal care is particularly beneficial for high pre-delivery risk births. There is no evidence from recent years that the findings of 1970 are not equally valid in the 1980s.     

Follicular dendritic cell accessory activity crosses MHC and species barriers

Productive follicular dendritic cell (FDC)-B cell interactions appear to involve critical ligand-receptor interactions. Immune complexes (IC) on FDC activate complement and provide FDC with a complement-derived CD21 ligand (CD21L), which bind CD21, while antigen in the IC binds on the B cell-BCR. Further, FDC-FcgammaRIIB binds Fc regions of antibodies in IC and reduces coligation of BCR and FcgammaRIIB minimizing an inhibitor of B cell activation. Given that Fc receptors and complement receptors bind immunoglobulins and complement fragments of other species, we reasoned that FDC accessory activity should cross MHC and species barriers. This prediction was tested using memory lymphocytes from OVA-immune mice and TT-immune humans in combination with FDC from murine lymph nodes and human tonsils. Human and murine FDC converted IC into potent immunogens (specific antibody increased from background to thousands of ng / ml). MHC barriers did not restrict this activity and human FDC worked with murine lymphocytes and murine FDC worked with human lymphocytes. Furthermore, stimulation via MHC-dependent allogeneic or zenogeneic mechanisms did not promote antibody production by FDC. Polyclonal responses stimulated by lipopolysaccharide and pokeweed mitogen were also promoted (10 - 100-fold) and anti-CD21 blocked FDC activity. These results substantiate the hypothesis that FDC are necessary for strong recall responses and that FDC-CD21L is critical.