Conditional Knockdown of Tubedown-1 in Endothelial Cells Leads to Neovascular Retinopathy

PURPOSE

Identification of novel proteins involved in retinal neovascularization may facilitate new and more effective molecular-based treatments for proliferative retinopathy. Tubedown-1 (Tbdn-1) is a novel protein that shows homology to the yeast acetyltransferase subunit NAT1 and copurifies with an acetyltransferase activity. Tbdn-1 is expressed in normal retinal endothelium but is specifically suppressed in retinal endothelial cells from patients with proliferative diabetic retinopathy. The purpose of this study was to investigate the importance of Tbdn-1 expression in retinal blood vessels in vivo.

METHODS

A bitransgenic mouse model that enables conditional knockdown of Tbdn-1 specifically in endothelial cells was produced and studied using molecular, histologic, and immunohistochemical techniques and morphometric analysis.

RESULTS

Tbdn-1-suppressed mice exhibited retinal and choroidal neovascularization with intra- and preretinal fibrovascular lesions similar to human proliferative retinopathies. Retinal lesions observed in Tbdn-1-suppressed mice increased in severity with prolonged suppression of Tbdn-1. In comparison to normal retina, the retinal lesions displayed alterations in the basement membrane of blood vessels and in the distribution of glial and myofibroblastic cells. Moreover, the pathologic consequences of Tbdn-1 knockdown in endothelium were restricted to the retina and the choroid.

CONCLUSIONS

These results indicate that the maintenance of Tbdn-1 expression is important for retinal blood vessel homeostasis and for controlling retinal neovascularization in adults. Restoration of Tbdn-1 protein expression and/or activity may provide a novel approach for treating proliferative retinopathies.

Treatment of endometriosis with a Nd:YAG tissue-contact laser probe via laparoscopy

The neodymium:yttrium-aluminum garnet (Nd:YAG) laser was used via laparoscopy in 84 patients complaining of infertility and/or pelvic pain. All patients in the study had biopsy-proven or visually confirmed pelvic endometriosis. The Nd:YAG laser was used in conjunction with sapphire probes as a touch technique on tissue. Problems usually encountered, such as mirror alignment, beam focus, and smoke plume, with carbon dioxide laser systems were avoided, and use of the laser in a liquid environment was possible. Restoration of fertility was seen in 39.7% with short follow-up; pain relief was excellent, especially in conjunction with uterosacral denervation.

Increased frequency of detection of human papillomavirus deoxyribonucleic acid in exfoliated cervical cells during pregnancy

Exfoliated cells of the uterine cervix obtained from women during pregnancy and at the time of their first postpartum examination were used to monitor the prevalence of human papillomavirus infections in this population and to study the natural fluctuations in viral expression. When deoxyribonucleic acid hybridization analysis alone was used to monitor the presence of human papillomavirus infection, 20.9% of our study population had results that were positive for human papillomavirus deoxyribonucleic acid during their first-trimester examinations. A dramatic increase in the percentage of women with positive results for human papillomavirus deoxyribonucleic acid was observed at the time of the patients' third-trimester examinations (46%). The overall increase in human papillomavirus-positive patients was a combination of a small number of patients who had positive results on their first examination and negative results on their second examination, and a larger number of patients who had negative results on their first-trimester examination and positive results for human papillomavirus deoxyribonucleic acid in the exfoliated cervical cells at the time of their third-trimester examination. The total percentage of patients with positive results for human papillomavirus deoxyribonucleic acid in their cervical cells at one or both assay points during pregnancy was 52.5%. Samples obtained at the postpartum examination demonstrated a dramatic decrease in the number of samples positive for human papillomavirus deoxyribonucleic acid (17.5%). This result was a combination of a large decrease in human papillomavirus-positive patients coupled with a small increase in detectable levels of human papillomavirus deoxyribonucleic acid in cervical samples from patients who had negative results on their previous examination. This study demonstrates a very high level of detectable human papillomavirus deoxyribonucleic acid in exfoliated cervical cells obtained during pregnancy and shows that the detectable levels of human papillomavirus deoxyribonucleic acid fluctuate during pregnancy.

Mechanism for human papillomavirus transmission at birth

We attempted to investigate mechanisms, in addition to sexual contact, by which human papillomaviruses associated with anogenital tract lesions could be transmitted. Samples of exfoliated cervical cells were obtained from 45 pregnant women and were assayed by Southern blot hybridization analysis for the presence of human papillomavirus nucleic acids. Twenty-five of the 45 women had cells positive for human papillomavirus deoxyribonucleic acid. A neonatal nasopharyngeal aspirate was obtained at term and analyzed for the presence of human papillomavirus deoxyribonucleic acid. We documented the presence of human papillomavirus deoxyribonucleic acid in the oral pharyngeal cavity of the neonates in 15 of 45 nasopharyngeal samples analyzed. Amniotic fluid was obtained from 13 patients when their membranes were artificially ruptured. These samples were assayed for the presence of human papillomavirus deoxyribonucleic acid; two of the 13 amniotic fluid samples contained human papillomavirus deoxyribonucleic acid. The detection of human papillomavirus deoxyribonucleic acid in the oral cavity of neonates is indicative of a perinatal mechanism of viral transmission. The detection of human papillomavirus deoxyribonucleic acid in the amniotic fluid may suggest an in utero mechanism of transmission. However, problems encountered in collecting the amniotic fluid samples preclude us from definitive interpretation of these data.

Prevention of maternal death in a Nigerian village

In a Nigerian village, the expected maternal mortality would be between 6 and 12 per 1000 live births, the most common causes of maternal death being obstructed labor, hemorrhage and eclampsia. Yet, over an 8 1/2-year period, when 2324 births occurred, the rate was 1.72 per 1000, of which 0.43 were due to obstetric complications. The four deaths were associated, respectively, with typhoid fever, tuberculosis and typhoid fever, infectious hepatitis and postpartum hemorrhage with dysentery. Using the experience gained in the village, recommendations are made for reducing maternal mortality in rural areas.

Birth intervals, survival and growth in a Nigerian village

Results are presented from an analysis of the intervals between births from Imesi, Western Nigeria. The mean interval following births of children who survived to 1 year was 35·03 months, but nearly half this value at 18·8 months following stillbirths or deaths under 1 year. Both these results confirm an early study done in the village (Martin, Morley & Woodland, 1964), and the role of post-partum sexual abstention as an explanation for these results is discussed. Attempts were made to look for effects of birth interval variation on the survival of the following child, but no strong trends emerged. Similarly, analyses of many growth variables by preceding and following birth intervals gave very little evidence of real effects. There were, however, hints of trends which were possibly caused by birth order biases; higher birth orders had been found to have correspondingly higher birth intervals. An intriguing result was that those children who had ever suffered from kwashiorkor showed a significantly higher preceding mean birth interval, and also a higher mean interval to the next birth.