Mikrobielle Keratitis

PURPOSE

To determine the risk factors and the influence of complementary/alternative medicines (CAM) for infectious keratitis in a monsoon-free region of the Sultanate of Oman.

STUDY DESIGN

Retrospective single center cohort study.

OUTCOME MEASURES

Demographic data, risk factors, and pathogens.

METHODS

Patients with purulent stromal keratitis admitted from 2001-2004 were evaluated for clinical and microbiological data, CAM use, duration of hospitalization, and outcome of treatment.

STATISTICS

chi(2)-test, Z-test.

RESULTS

A total of 320 patients (326 eyes) out of 7,524 admissions had severe infectious stromal keratitis requiring inpatient treatment. The average age was 35.1+/-2.5 years (range 1.5-63 years), the male:female ratio was 2:3 in the age group >or=13 years and 2:1 in the age group <or=12 years. Unsuccessful treatment by traditional healers prior to presentation was recorded for 203 patients (62.3%). Ocular risk factors included severe trachomatous dry eye conditions, meibomianitis and soft contact lens overwear. Systemic compromising risk factors were diabetes mellitus and medical immunosuppression. A total of 215 patient eyes (66%) had delayed or no healing (therapy drop-outs), and hospitalization (45 days) was significantly prolonged compared to the 111 antibiotic responders (26 days) (p<0.001). All eyes of patients with prior CAM had worse vision at admission and after therapy (p<0.001), and 97 eyes of patients with uncontrolled diabetes (p<0.001) and 68 eyes of patients with immunosuppression (p<0.001) had a poor visual outcome (vision <0.1). Thirteen eyes perforated. A negative microbiological result correlated with worse final vision (p<0.05). All 13 perforated eyes had received prior CAM (p<0.001).

CONCLUSIONS

Trachoma, trauma and contact lens overwear are significant risk factors for infectious keratitis in Oman and correlate with specific age groups. Delay in treatment due to the first-line utilization of CAM showed a significant adverse impact on outcome.

Lung angiotensin receptor binding characteristics during the development of monocrotaline-induced pulmonary hypertension

Alterations in lung angiotensin converting enzyme (ACE) activity in monocrotaline (MCT)-induced pulmonary hypertension in rats have suggested a pathophysiologic role for angiotensin II (AII) in pulmonary vascular remodeling. ACE inhibitors suppress MCT-induced pulmonary hypertension; however, losartan, an angiotensin type 1 (AT1) receptor antagonist, was without impact. The present study examined AII receptor binding characteristics by radioligand binding during the development of MCT-induced pulmonary hypertension. Saturation binding isotherms for [125I]AII binding to membrane preparations from rat lung were performed at 4, 10, and 21 days following a single injection of MCT (60 mg/kg) or saline vehicle. Right ventricular hypertrophy, an index of pulmonary hypertension, increased at 21 days post-MCT. Saturation binding isotherms revealed a single, high affinity site for [125I]AII binding in lung membranes from MCT-treated and control rats, with no change in receptor affinity or density during the development of pulmonary hypertension. Competition displacement binding demonstrated that the AT1 receptor predominates in lung membranes from control rats, with no alterations in AII receptor subtype distribution following MCT treatment. In summary, these results suggest that the AT1 receptor subtype predominates in rat lung and does not contribute to the development of MCT-induced pulmonary hypertension.

Characterization of renin activity in brown adipose tissue

Angiotensin (ANG) II plays a vital role in blood pressure regulation and body fluid homeostasis. Although many peripheral tissues synthesize components of the renin-ANG system, very few synthesize all of the major components involved in the generation ofANG II. This study used interscapular brown adipose tissue (ISBAT) as a model system to evaluate the mechanism of ANG II generation in an extrarenal tissue. Polymerase chain reaction analysis of DNA from ISBAT demonstrated angiotensinogen gene expression; however, renin gene expression was not detected. Renin activity that was not completely derived from the residual blood pool was detected in ISBAT homogenates. Kinetic parameters for renin activity were similar in ISBAT and adrenal gland. Renin activity was partially inhibited by anti-renin antibody and completely inhibited by a specific rat renin inhibitor. Bilateral nephrectomy did not decrease renin activity in ISBAT. Western blot analysis, employing two species-specific renin antibodies, indicated the presence of a variety of isoforms of renin in ISBAT. The presence of renin activity in isolated brown adipocytes demonstrated that the enzyme is localized to adipocytes. The release of immunoreactive ANG peptides from ISBAT slices over 3 h indicated de novo synthesis. These studies support the existence of a local renin-ANG system in ISBAT and suggest involvement of renin in the formation of ANG II.