Pathophysiology of Hypertensive Retinopathy

The effects of systemic hypertension on the posterior segment of the eye are discussed under the headings of hypertensive choroidopathy, hypertensive retinopathy, and hypertensive optic disc edema. The sympathetic nervous control and autoregulatory mechanisms of the retinal and chorodial vasculatures are briefly reviewed. In hypertensive choroidopathy focal occlusion of choriocapillaris leads to necrosis of retinal pigment epithelium (Elschnig spots). Hypertensive retinopathy is described in vasoconstrictive, exudative, and sclerotic phases, followed by complications of the sclerotic phase. Hypertensive optic disc edema is influenced by the blood supply and extracellular tissue fluid pressure of the optic nervehead. In baboons with hypertensive disc edema, accumulation of axoplasmic components is observed in the optic nervehead.     

Effects of intravitreal indocyanine green injection in rabbits

PURPOSE: To report the clinical, electrophysiologic, and histologic findings of different concentrations of indocyanine green (ICG) injected into the vitreous cavity of rabbit eyes. METHODS: Forty-two rabbits underwent intravitreal injection of 0.1 mL of ICG in three different concentrations: 0.5 mg/mL (250 mOsm), 5 mg/mL (270 mOsm), and 25 mg/mL (170 mOsm). Fellow eyes were injected with 0.1 mL of balanced salt solution. Biomicroscopy, ophthalmoscopy, electroretinography, fluorescein angiography, and histologic evaluation were performed. RESULTS: Eyes injected with 0.5 mg/mL of ICG showed b-wave latency delay on the first day after injection. Eyes injected with 5 mg/mL of ICG showed b-wave latency delay and decreased b-wave amplitude on the first and seventh days after injection; delayed a-wave latency on the first day after injection was also observed. Eyes injected with 25 mg/mL of ICG showed b- and a-wave amplitude and latency abnormalities during the entire follow-up. Direct correlation of increasing retinal edema proportional to the progressively increasing ICG concentrations was shown on histologic evaluation. CONCLUSION: Intravitreal ICG injection in rabbit eyes may impair retinal function and morphology proportional to the progressively increasing ICG dosages.     

Early prophylactic inhaled beclomethasone in infants less than 1250 g for the prevention of chronic lung disease

OBJECTIVE:

Inflammation plays an important role in the development of chronic lung disease (CLD), which has become a major cause of morbidity in surviving infants less than 1250 g at birth. The authors hypothesized that the progression of this inflammation and, therefore, the establishment of CLD would be decreased with the use of early prophylactic inhaled corticosteroids. Short, and long term respiratory and neurodevelopmental outcomes were also examined.

DESIGN:

A double-blind, randomized placebo controlled trial.

SETTING:

Level-III neonatal intensive care unit.

POPULATION STUDIED:

Sixty infants less than 1250 g at birth, diagnosed with respiratory distress syndrome and requiring ventilatory support at 72 h of age were enrolled in the study.

INTERVENTION:

Infants enrolled received either placebo or beclomethasone diproprionate by a metered dose inhaler, which was used in-line with the ventilator circuit while the infant was ventilated and then via a spacer until 28 days of age.

RESULTS:

Thirty infants were given beclomethasone and 30 were given placebo. There were two deaths in each group. Among the surviving infants, the frequency of moderate-to-severe CLD was 17% in each study group. Mean time to extubation was not different for beclomethasone compared with placebo at 16.4 and 12.5 days (P=0.12), respectively. The requirement for intravenous corticosteroids was lower in the beclomethasone-treated group (RR 0.67, 95% CI 0.43 to 1.04), although this difference was not statistically significant. The incidence of growth failure, infection and intraventricular hemmorhage did not differ between the two groups. Long term outcomes were not different with respect to the incidence of respiratory re-admissions, cerebral palsy, developmental delay, blindness or deafness.

CONCLUSIONS:

Early treatment with inhaled beclomethasone diproprionate did not reduce the incidence of CLD or decrease the duration of mechanical ventilation. The decrease in intravenous corticosteroid use was not statistically significant. Long term outcome was not affected.     

Autologous transplantation of retinal pigment epithelium after mechanical debridement of Bruch's membrane

PURPOSE: To determine whether transplantation of autologous retinal pigment epithelium (RPE) will prevent atrophy of the choriocapillaris and loss of photoreceptors in an area in which the RPE has been mechanically debrided from Bruch's membrane. METHODS: Abrasive debridement of RPE was performed with a metal cannula after localized retinal bleb detachments in two separate areas of the rabbit retina. The RPE cell suspension aspirated from one of the debridement sites was transplanted to the other. The debridement-only site served as control. The transplant and control sites were evaluated after 30 days by color fundus photography, fluorescein angiography, light microscopy and transmission electron microscopy. RESULTS: Compared with debridement only, debridement plus transplantation of RPE resulted in more complete repopulation of the bare Bruch's membrane surface with relative preservation of choriocapillaris and photoreceptors. CONCLUSION: Autologous transplantation of RPE onto an abrasively debrided Bruch's membrane decreases choriocapillaris atrophy and photoreceptor loss.     

Factors predictive of 5-year survival after transarterial chemoembolization for inoperable hepatocellular carcinoma

BACKGROUND: Transarterial chemoembolization (TACE) is widely used for unresectable hepatocellular carcinoma (HCC), but the long-term survival benefit remains unclear. METHODS: Pretreatment variables were analysed for factors predictive of actual 5-year survival from a prospective database of patients with inoperable HCC treated by TACE between 1989 and 1996. RESULTS: Complete 5-year follow-up (median 91 months) was obtained for 320 patients who underwent a median of 4 (range 1-41) TACEs. Median tumour size was 9 (range 1-28) cm. There were 25 5-year survivors (8 per cent), including eight with tumours larger than 10 cm in diameter and three with portal vein branch involvement. On univariate analysis, female gender (P = 0.037), absence of ascites (P = 0.028), platelet count below 150 x10(9) per litre (P = 0.011), albumin concentration greater than 35 g/l (P = 0.04), alpha-fetoprotein level below 1000 ng/ml (P = 0.007), unilobar tumour (P = 0.027), fewer than three tumours (P = 0.015), absence of venous invasion (P = 0.011), and tumour diameter less than 8 cm (P = 0.021) were significant predictors of 5-year survival. Albumin concentration greater than 35 g/l (P = 0.011), unilobar tumour (P = 0.012) and alpha-fetoprotein level below 1000 ng/ml (P = 0.014) were independent prognostic factors on multivariate analysis. CONCLUSION: Five-year survival is possible with TACE for inoperable HCC, even in some patients with advanced tumours. Unilobar tumours, alpha-fetoprotein level below 1000 ng/ml and albumin concentration greater than 35 g/l were factors predictive of 5-year survival.     

Molecular basis of opioid dependence: role of signal regulation by G-proteins

1. Morphine and opiate narcotics are potent analgesics that have a high propensity to induce tolerance and physical dependence following their repeated administration. 2. The molecular basis of opiate dependence has not been completely elucidated, although the participation of opioid receptors is a prerequisite. Cellular dependence on opioids is believed to result from the chronic stimulation of opioid-regulated signalling networks. 3. As G-protein-coupled receptors, the opioid receptors must rely on heterotrimeric G-proteins for signal transduction. Recent advances in our understanding of G-protein signalling have unveiled novel signalling molecules and mechanisms, some of which may be intricately involved in the manifestation of opiate dependence. 4. In the present review, we will attempt to trace chronic opioid signals along elaborate G-protein-regulated pathways.     

Ventral hernia repair: a study of current practice

Ventral wall hernias are common; despite this, there are no guidelines on the best surgical management. The aim of this study was to examine the types of repair in use for abdominal wall hernias in the West of Scotland over a 3-month period. Data were gathered on 120 patients. There were 60 incisional, 32 umbilical, and 28 epigastric hernias. The main indication for repair was pain (78%), while 12 patients (10%), presented acutely with incarceration or strangulation. The most common method of repair was sutured (55%), followed by mesh (29%) and Mayo repair (16%). There was no correlation between use of mesh and hernia size or whether repair was for a recurrent hernia. Surgical practice varies widely in the repair of ventral wall hernias. Clinical trials are required to establish the best method of repair for this common condition. Electronic Publication