Histopathological characterisation of effects of the mouse Pax6 missense mutation on eye development

Mutations in PAX6/Pax6 lead to a variety of ocular anomalies in humans and mice. The aim of the study was to characterise the ocular abnormalities caused by the missense Pax6^Leca4 mutation and compare them to published observations on Pax6 alleles that are functionally equivalent to Pax6⁻ null alleles (such as Pax6^Sey and Pax6^Sey-Neu) and human inherited eye diseases. Ocular features of homozygous Pax6^Leca4/Leca4 and heterozygous Pax6^Leca4/+ embryos at E12.5-E18.5, heterozygous Pax6^Leca4/+ young mice at P18 and heterozygous Pax6^Leca4/+ adults at 12 weeks were analysed histologically with their wild-type Pax6^+/+ littermates. Homozygous Pax6^Leca4/Leca4 fetuses died perinatally with no eyes although an optic cup rudiment with pigmented cells developed. Pax6^Leca4/+ mice were microphthalmic and a range of other severe ocular phenotypes affected both the anterior and the posterior segments. In contrast to Pax6^+/−, the Pax6^Leca4/+ eyes had no goblet cells in the corneal epithelium, the iris was not hypoplastic and there was no lens-corneal epithelial plug. However, microphthalmia was more severe, corneal vascularisation occurred earlier (during fetal stages), pigmented cells were present in the vitreous and corneal stroma and the ciliary body was malformed or abnormal. These results show that, although Pax6^Leca4/+ lacked some eye abnormalities commonly seen in Pax6^Sey/+ and Pax6^Sey-Neu/+ eyes, in most respects their eyes were more severely affected. These differences probably reflect both differences between the Pax6^Leca4 and the Pax6^Sey-Neu mutations and differences in modifier gene expression in different genetic backgrounds. The presence of pigmented cells in the cornea is a novel observation. Some Pax6^Leca4/+ ocular abnormalities were similar to those present in human Peters' anomaly and persistent hyperplastic primary vitreous (PHPV) so Pax6^Leca4/+ mice provide a useful model for some inherited eye diseases.     

Fetal stabilization for antenatally diagnosed diaphragmatic hernia

BACKGROUND/PURPOSE: Infants with congenital diaphragmatic hernia have pulmonary hypoplasia resulting in persistent pulmonary hypertension of neonates (PPHN), which is the main contributor to both high mortality and morbidity. The pulmonary artery bed in patients with congenital diaphragmatic hernia (CDH) is underdeveloped and is very sensitive to slight stimuli. It is, therefore, vital to avoid any factors that might increase pulmonary vascular resistance during the perinatal treatment of these patients. Recently, fetal anesthesia for perinatal stabilization in patients with CDH has been reported. However, the efficacy of this method remains controversial. The aim of this study is to analyze the benefits of fetal stabilization using fetal anesthesia in patients with CDH. METHODS: The authors have seen 9 cases of antenatally diagnosed CDH and attempted fetal stabilization. The indication for fetal stabilization was a lung thoracic ratio of less than 0.2, without any severe associated anomalies. The protocol for fetal stabilization was (1) monitoring the fetal respiratory movement and heart beat by ultrasonography, (2) the administration of morphine (20 to 30 mg) and diazepam (5 mg) to the mother, (3) the confirmation of any interruptions in fetal movement followed by a cesarean section, (4) pancuronimum (0.5 mg) was given through the umbilical vessels, (5) intubation before clamping of the umbilical cord, and (6) high-frequency oscillatory ventilation (HFO) without bagging. RESULTS: The lung-thratic ratio (LTR) was between 0.06 to 0.17 (average, 0.10+/-0.04). Operation was performed in 7 of 9 patients at between 2.5 and 27 hours after birth. The overall survival rate was 66.7% (6 of 9). All of the patients who underwent operation within 5 hours after birth survived. CONCLUSIONS: Perinatal stabilization using fetal anesthesia was found to be effective in preventing PPHN and shortening the period of preoperative stabilization. It also improved the survival rate of patients with severe CDH.     

Cranial melioidosis with extradural extension after a fall in the bathroom

A 32-year-old diabetic male, with a past history of head injury and seizures, presented with a painful swelling over his forehead present for the past three months. Cranial MRI demonstrated the presence of a scalp collection with extradural extension through a bony defect. Biopsy from the area showed caseating necrosis suggestive of tuberculosis. Although the patient failed to return for initiation of anti-tubercular therapy for the next 11 months, the swelling did not progress, and there were no constitutional symptoms. The indolent nature of the swelling prompted re-evaluation and delayed cultures of pus from the collection grew Burkholderia pseudomallei.     

HIV–tuberculosis co–infection in an Indian scenario: The role of associated evidence of immunosuppression

ObjectiveTo determine the relationship between tuberculosis and the degree of immunosuppression as determined by CD4 count. The impact of immunosuppression on the severity of tuberculosis was also studied.MethodsA retrospective analysis was performed in patients newly diagnosed with HIV infection and antiretroviral therapy (ART)-naive patients with known HIV seropositivity. All patients were diagnosed with active tuberculosis between January 2008 and December 2010, based on review of their medical records. Patients on chemoprophylaxis for opportunistic infection were excluded. Pattern and severity of tuberculosis, associated stigmata of immunosuppression, and CD4 counts were noted.ResultsOf 140 patients satisfying the inclusion criteria, 52 had mild tuberculosis with no other evidence of immunosuppression, 52 had tuberculosis of variable severity with associated evidence of immunosuppression, and 36 had severe tuberculosis with no other evidence of immunosuppression. The CD4 count was highest in the first group [(109.2±99.9) cells/μL] and least in the second group [(58.4±39.8) cells/μL], and the difference was statistically significant (P=0.004). No statistical difference was observed in the CD4 count between those with mild tuberculosis and those with severe tuberculosis.ConclusionsIn developing countries with a high prevalence of tuberculosis in the general population, the possibility of incidental tuberculosis in patients with HIV should always be considered. CD4 count does not appear to influence the severity of tuberculosis. The presence of concomitant evidence of immunosuppression in the form of category B and C conditions is indicative of underlying immunosuppression and associated with a significantly lower CD4 count.     

Endothelial Cilia Are Essential for Developmental Vascular Integrity in Zebrafish

The cilium is a signaling platform of the vertebrate cell. It has a critical role in polycystic kidney disease and nephronophthisis. Cilia have been detected on endothelial cells, but the function of these organelles in the vasculature remains incompletely defined. In this study, using genetic and chemical genetic tools in the model organism zebrafish, we reveal an essential role of cilia in developmental vascular integrity. Embryos expressing mutant intraflagellar transport genes, which are essential and specific for cilia biogenesis, displayed increased risk of developmental intracranial hemorrhage, whereas the morphology of the vasculature remained normal. Moreover, cilia were present on endothelial cells in the developing zebrafish vasculature. We further show that the involvement of cilia in vascular integrity is endothelial autonomous, because endothelial-specific re-expression of intraflagellar transport genes in respective mutants rescued the intracranial hemorrhage phenotype. Finally, whereas inhibition of Hedgehog signaling increased the risk of intracranial hemorrhage in ciliary mutants, activation of the pathway rescued this phenotype. In contrast, embryos expressing an inactivating mutation in pkd2, one of two autosomal dominant cystic kidney disease genes, did not show increased risk of developmental intracranial hemorrhage. These results suggest that Hedgehog signaling is a major mechanism for this novel role of endothelial cilia in establishing vascular integrity.     

Penetrating injury of the cornea by a barbed fish hook and its surgical management by “Cut-it out technique”

Fishing is a worldwide pastime enjoyed by millions of people. Ocular fishing injuries though uncommon may cause potentially devastating ocular trauma. We report a rare case of penetrating injury of the cornea by a barbed fish hook and its successful surgical management by “cut-it out technique”. We are discussing the various techniques available for removal of fish hooks. The hook can be successfully removed with minimal trauma to ocular structures by understanding the structure of the fish hook and by employing the appropriate method of extraction.