New techniques and instruments for lens implantation

Although most of the new techniques and new instrumentation for intraocular lens implantation are related to foldable intraocular lenses or sutured posterior chamber lenses, there are some intriguing new concepts in intraocular lens techniques unrelated to these two areas.     

Recombinant human growth hormone in infants and young children with chronic renal insufficiency

Children with chronic renal insufficiency (CRI) secondary to congenital structural abnormalities frequently have significant growth retardation by 2 years of age. In a multicenter placebo-controlled study of the use of recombinant human growth hormone (rhGH), 30 of 125 (24%) participants were<2.5 years of age at enrollment. Since the treatment arms of the study were balanced for age at randomization, data for these patients were examined for efficacy and safety. During the first 2 years of the study, approximately two-thirds of the patients (n=19) received rhGH 0.05 mg/kg per day subcutaneously and one-third (n=11) received placebo injections. At entry into the study, the mean (± SD) calculated creatinine clearance was 29.2±14.3 (range 12.0–63.7) ml/min per 1.73 m² in the rhGH-treated group and 23.3±15.1 (range 8.0–59.4) ml/min per 1.73 m² in the placebo-treated group. The 1st year growth rate was 14.1±2.6 cm/year for the rhGH-treated group and 9.3±1.5 cm/year in the placebo-treated group (P<0.00005). During the 2nd year of the study, the growth rate was 8.6±1.2 cm/year in the rhGH-treated group compared with 6.9±1.0 in the placebo groupP=0.025). The height standard deviation score was +2.0±0.7 for the rhGH-treated group compared with –0.2±1.1 in the placebo-treated group (P<0.00005) during the 2 years of the study. Minor adverse events occurred with similar frequency in both groups. These data suggest that rhGH is efficacious and safe in children with CRI under age 2.5 years. rhGH therapy may correct significant loss of growth at this age when used in conjunction with optimal medical management.     

Calreticulin is transported to the surface of NG108-15 cells where it forms surface patches and is partially degraded in an acidic compartment

Although calreticulin (Crt) is primarily localized to the endoplasmic reticulum (ER), our results using biotinylation and immunocytochemical methods indicate that a small but significant amount of Crt is present and forms large patches on the surface of NG108-15 cells (a mouse neuroblastoma-rat glioma hybrid cell line). (35)S-labelled Crt molecules begin to reach the cell surface after only 10 min of labelling and disappear slowly from the cell surface. After 4 hr of labelling, approximately half of the newly synthesized Crt molecules are on the cell surface. We believe that some Crt molecules may escape from the KDEL receptor-mediated salvage pathway as they are synthesized and proceed through the secretory pathway to the cell surface. Immunoprecipitation from the culture medium shows that Crt is not released from the cell surface to the medium, suggesting tight binding to surface molecules. NH(4)Cl can block the degradation of Crt; therefore, Crt is presumably degraded in the lysosome pathway. However, blockage of the disappearance of surface Crt is less efficient than that of internal Crt. This suggests that the disappearance of Crt from the cell surface may not be due solely to its degradation, but may reflect transport into another cell compartment such as the ER.     

Effects of cataract and scotoma on visual acuity: a simulation study.

Central field loss (CFL) and cataract both decrease visual acuity. For patients with CFL, visual acuity is further reduced when the acuity target is more visually complex. We tested visual acuity for targets of varying complexity (letters alone, letters flanked by one or two x's on each side, and words) in subjects with normal vision and in the presence of a simulated cataract, simulated scotoma, and their combination (scotoma + cataract). Visual acuity was best with normal vision and worst with scotoma + cataract for all of the acuity targets. There was little difference in visual acuity between the letters alone and flanked letters, and visual acuity was best for words under all vision conditions. The cataract had a greater impact on visual acuity when the subject's central visual field was clear (normal vision) than when it was occluded by the simulated scotoma.     

STDs and family planning clinics: a regional program for Chlamydia control that works

Joint meetings between the members of the US Family Planning Services Program and the STD Program of Region X (comprising Alaska, Idaho, Oregon, and Washington) from fall 1986 through spring 1987 led to the screening and treatment of patients with chlamydia. Samples from patients were sent to state health department laboratories in Idaho, Washington, and Oregon. A direct fluorescent antibody (DFA) slide technique was used to process the cervical smears. Clinic visit record (CVR) information and laboratory results were collected by a central data management company, and sent to CDC and Region X researchers. 6 clinics in 3 of the states collected 2 cervical samples from each of 3000 patients, 1 for smear (DFA slide) and 1 for tissue culture over a 4-month period. During the 1988-1990 period, 136 clinics in the region supplied patient information and test results on over 300,000 samples. Overall, positive rates for chlamydia in the region went from a high of 10.9% in the 1st quarter of 1988 to 6.8% in the last quarter of 1990, with an overall declining trend. This amounted to an almost 37% decrease within the region. When analyzed by state, the positivity rates and decreases were relatively similar: Alaska, 12.2% to 10.0% positivity (18% decrease); Idaho, 10.5% to 8.0% (24% decrease); Oregon, 8.9% to 6.9% (22% decrease); and Washington, 9.3% to 6.6% (29% decrease). In patients 17 years of age and younger, positive rates for chlamydia fell 19%, from 12.2% in 1988 to 9.9% in 1990. In women 18-19 years old and women 20-24 years old, the rates fell 24% and 31%, respectively. Larger decreases in chlamydia rates were found among women in the 25-29 year age group (31% reduction) and in those 30 years old and older (44% reduction). Infection rates decreased in all race/ethnic groups, except Asians. Approximately 2/3 of the women with positive chlamydia tests had no apparent symptoms of disease. Conversely, the presence of certain clinical indicators seemed to correlate with the probability of a positive test result.