Enhanced engraftment of hematopoietic progenitor cells in mice treated with granulocyte colony-stimulating factor before low-dose irradiation: implications for gene therapy

Gene therapy for inherited disorders of blood cells will require both efficient methods for stable gene transfer and nonablative bone marrow conditioning regimens to allow engraftment of modified hematopoietic progenitor cells (HPCs). We have used a sensitive murine system for detecting HPC engraftment using congenic C57BL/6 mice that differ at the Ly5 locus, which encodes the leukocyte common antigen. The system relies on the ability of monoclonal antibodies with specificity for Ly5.1 and Ly5.2 (revised nomenclature: CD45.1 and CD45.2, respectively) to distinguish donor and recipient peripheral blood leukocytes after transplantation of purified Sca-1+ bone marrow-derived HPCs. No detectable engraftment occurred in nonirradiated recipient mice, even when as many as 2.0 x 10(6) SCa-1+HPCs were transplanted. However, in mice receiving total body irradiation (TBI), engraftment increased as a function of pretransplantation radiation dose, number of transplanted cells, and time after transplantation. Moreover, mice receiving either granulocyte colony-stimulating factor (G-CSF) or G-CSF+ stem cell factor before low-dose TBI (160 cGy) exhibited a marked increase in engraftment compared with mice receiving a vehicle control before low- dose TBI (18.9% and 20.6% v 5.6% at a 1 month, respectively; 29% and 35% v 15.1% at 4 months, respectively). Use of growth factor pretreatment even allowed TBI doses as low as 30, 70, or 120 cGy to achieve significant engraftment of donor progenitors (0.3%, 1.5%, and 6.8% at 1 month, respectively; 1.7%, 5.8%, and 13.9% at 4 months, respectively). All animals remained healthy during the observation periods. Thus, growth factor preconditioning of the recipient followed by low-dose TBI may provide an optimal balance between safety and efficacy in achieving required levels of engraftment for gene therapy of blood disorders.     

Differentiation of pulmonary parenchymal consolidation from pleural disease using the sonographic fluid bronchogram

The nature of pleural-based thoracic collections may be sonographically confusing. To help lessen this confusion, the fluid bronchogram, a useful sonographic sign of pulmonary parenchymal consolidation, is described. Bronchi containing fluid in consolidated lung can be identified using ultrasound.     

Modulation of responses to optic flow in area 7a by retinotopic and oculomotor cues in monkey

Perception of two- and three-dimensional optic flow critically depends upon extrastriate cortices that are part of the 'dorsal stream' for visual processing. Neurons in area 7a, a sub-region of the posterior parietal cortex, have a dual sensitivity to visual input and to eye position. The sensitivity and selectivity of area 7a neurons to three sensory cues - optic flow, retinotopic stimulus position and eye position - were studied. The visual response to optic flow was modulated by the retinotopic stimulus position and by the eye position in the orbit. The position dependence of the retinal and eye position modulation (i.e. gain field) were quantified by a quadratic regression model that allowed for linear or peaked receptive fields. A local maximum (or minimum) in both the retinotopic fields and the gain fields was observed, suggesting that these sensory qualities are not necessarily linearly represented in area 7a. Neurons were also found that simply encoded the eye position in the absence of optic flow. The spatial tuning for the eye position signals upon stationary stimuli and optic flow was not the same, suggesting multiple anatomical sources of the signals. These neurons can provide a substrate for spatial representation while primates move in the environment.      

Synthetic or natural surfactants

Surfactant replacement therapy is one of the most studied interventions in neonatal medicine, with many thousands of infants having been enrolled in randomized clinical trials. It is clear that surfactant therapy reduces neonatal mortality and the risk of pulmonary air leaks in babies with or at risk of developing respiratory distress syndrome. Yet some doubts linger over other aspects of this therapy, despite it having been an acceptable and proven therapy for the past 7–10 years. As regards timing of treatment, the earlier the better, with true prophylaxis being reserved for babies of less than 28 weeks' gestation. Natural surfactant preparations containing surfactant proteins B and C act more rapidly than their synthetic protein-free counterparts and probably also have a greater impact on reducing neonatal mortality and pulmonary air leaks. Fears raised about immunological effects, prion transmission and chemical contamination of natural surfactants have not been substantiated. Long-term follow-up studies do not show any differences in outcome between treated and non-treated infants, except that the incidence and severity of retinopathy of prematurity might be reduced by treatment with natural surfactant. Further research is needed and this will include more detailed follow-up studies, newer indications for surfactant therapy and the testing of newer preparations with synthetic peptides or protein analogues added.     

Orthotopic cardiac transplantation: evaluation with CT

As cardiac transplantation has become widely available, computed tomography (CT) of the chest has played a useful role in the examination of patients after heart transplantation. To determine anatomic features related to the procedure, the authors evaluated 59 scans in 46 patients who had undergone orthotopic cardiac transplantation. Aortic anastomosis (seen in 98% of scans) and altered spacing between the great vessels (83%) proved to be the most common and most reliable findings. Other features including atrial anastomosis, high main pulmonary artery segment, remnant superior vena cava, and cardiac reorientation were also seen. Accurate interpretation of adenopathy, mediastinal abscess, and pericardial effusion will be enhanced in these patients through a better understanding of the cardiovascular-pericardial complex, which is afforded by CT.     

Experiences of special gynaecological services for children and adolescents: a descriptive study

Gynaecological examination of girls during childhood is undertaken somewhat infrequently. These genital examinations should not be taboo or a frightening experience for the girl, for her parents or for the physician. Studies of children suspected of sexual abuse have paid attention to the wide variety of gynaecological conditions already present in childhood. In 1988 we founded a special gynaecological outpatient clinic for girls under 16 y of age at a university hospital to develop the special knowledge and skills needed in children's gynaecology. In this gynaecological clinic for children and adolescents we were able to gain and offer expert knowledge of the problems of this age group. In this special clinic for children, gynaecological examination by special techniques and sonography led to a diagnosis in 71% of the patients without any instrumentation. Children and adolescent girls in need of special gynaecological care should be recognized specifically. Particular attention should be paid to the gynaecological care of victims of child sexual abuse and mentally or physically handicapped girls. In good co-operation with the girl, a gynaecological examination can become a positive experience during the development of female identity.     

Preventing drug-related morbidity--determining valid indicators.

OBJECTIVE: To describe the process that is being undertaken to validate a series of indicators for preventable drug-related morbidity - originally developed in the US - for application in the UK health care system. DESIGN: A two-round Delphi questionnaire survey after a preliminary validation of the indicators within the University of Manchester School of Pharmacy. SETTING: A primary care study set in the UK. STUDY PARTICIPANTS: A purposively selected sample of general practitioners with a specific responsibility for prescribing-related issues (n = 6) and pharmacists actively involved in medication review in primary care (n = 10). MAIN OUTCOME MEASURES: The establishment of consensus among the participants that an indicator reflected preventable drug-related morbidity in primary care. RESULTS: After preliminary validation, 37 of the original 57 US indicators were retained. The Delphi panel generated 16 additional new indicators in the first round. At the end of the second round, the pre-defined level of consensus was reached for 29 indicators (19 of the US generated indicators; 10 generated by the panel in the first round). CONCLUSIONS: The Delphi results highlighted differences in both the clinical perspective and, possibly, philosophical viewpoints of health professionals practising in the UK and US health care systems. Further work, located in both primary and secondary care, is now in progress to operationalize the indicators. This process will form a key part of the refining, and hence further validation, of the indicators. The future development of prospective medical-record-based indicators should facilitate a reduction in the human, clinical, and economic burden of drug-related morbidity.     

Exogenous gamma-linolenic acid alters hormone stimulated cyclic AMP levels in U937 cells

Polyunsaturated fatty acids are selectively cytotoxic in culture. Incorporation of these fatty acids leads to profound changes in membrane fatty acid composition which in turn may alter the activity of transmembrane receptor/effector systems. In U937 cells, hormone stimulated production of cyclic AMP can be reduced by 30% following incubation with gammalinolenic acid (18:3n-6). It is suggested that β-adrenoceptor number, subtype and adenylyl cyclase stimulation may be regulated by alterations in membrane fatty acid composition as a result of changes in the levels of polyunsaturated fatty acids and alterations in eicosanoid production.     

Cryoretinopexy for proliferative diabetic retinopathy

Cryoretinopexy can be used in the management of proliferative diabetic retinopathy. Indications include retinal neovascularization following photocoagulation or with opaque media, and anterior segment neovascularization. Of the six eyes in five patients treated with transconjunctival cryoretinopexy only one demonstrated regression of neovascularization; in this group, vision improved in two eyes, remained the same in three eyes and decreased in one eye. Of the 14 eyes in 14 patients treated with anterior transscleral cryoablation 5 demonstrated regression of posterior segment neovascularization and 2 demonstrated regression of anterior segment neovascularization; in this group, vision improved in 3 eyes, remained the same in 2 eyes and decreased in 9 eyes. No complications were associated with transconjunctival therapy, whereas uveitis (in 14 eyes), vitreous hemorrhage (in 2 eyes) and traction retinal detachment (in 5 eyes) were noted following transscleral therapy. Further studies are required to determine the risk/benefit ratio of cryoablation for proliferative diabetic retinopathy.