The incidence of refractive errors among school children in Hong Kong and its relationship with the optical components

This study aims to provide information about the prevalence of refractive errors among Chinese school children in Hong Kong, and its relationship with the optical components of the eye. Subjective refraction, corneal curvatures and ocular biometry were performed on 383 school children from age six to 17 years. The prevalence of myopia increases from 30 per cent at age six to seven to 50 per cent (girls) and 70 per cent (boys) at age 16–17. The mean spherical equivalent refraction gradually changes from plano at age six to seven to -2.00 D of myopia at age 1617. Our results are different from Caucasian data but comparable with those of other studies of Chinese in Asia. The increase in myopia correlates well with the axial length of the eye. Further studies are needed to investigate the cause for the development of myopia.     

Morgagni: His book, vision and views on hepatic coma

The study of pathological anatomy reached a culmination in the magnum opus of Morgagni, The Seats and Causes of Diseases. It represented an innovative way of looking at the patient and his illness, a change that Foucault described as occurring in the 18th century. Physicians saw symptoms penetrating the body and converging upon an organ. We suggest that Morgagni and his fellow workers derived their vision from the practice of visual perspective discovered by Italian Renaissance artists. Perceiving in three dimensional terms, Morgagni added spatial depth to our understanding of disease. His acute vision was brilliantly displayed in his views of hepatic coma. He was among the first to provide the clinical-pathological associations of acute liver failure. The limitations of gross morphology precluded a complete elucidation of the disorder.     

ANGIOTENSIN II ACTIVATES PRESSOR AND DEPRESSOR SITES OF THE PONTOMEDULLA THAT REACT TO GLUTAMATE

1. In cats anaesthetized with a mixture of α-chloralose (40 mg/kg) and urethane (400 mg/kg) and in rats anaesthetized with a mixture of α-chloralose (60 mg/kg) and urethane (800 mg/kg), changes in systemic arterial pressure (SAP), heart rate (HR) and sympathetic activities of vertebral (VNA) and renal (RNA) nerves were determined following the micro-injection of angiotensin II (AngII; 0.16 mmol/L; 50 nL) into the pressor and depressor sites of the pontomedulla previously reacted to a microinjection of monosodium l -glutamate (Glu; O.1 mol/L; 50 nL). Pressor sites included gigantocellular tegmental field (FTG) and dorsal medulla (DM) and rostral ventrolateral medulla (VLM). The depressor site was the caudal VLM (CVLM). The effects of losartan (1 mmol/L; 50 nL), a specific AT₁ receptor non-peptide antagonist for AngII, on responses induced by AngII in the VLM, DM and CVLM were also determined. 2. In 30% of pressor sites in the FTG, 55% in the VLM and 67% in the DM and in 76% of depressor sites in the CVLM previously exposed to Glu, microinjection of AngII to the same site produced pressor or depressor responses similar to that of Glu, but smaller in magnitude, particularly in the pressor VLM. Changes in both VNA and RNA induced by AngII were also smaller than those induced by Glu, particularly RNA from DM activation. 3. In the dorsal motor nucleus of the vagus, AngII, as Glu, produced marked bradycardia, but again this was smaller in magnitude than the bradycardia produced by Glu. 4. In rats, in the DM near or around the nucleus of the solitary tract where Glu increased SAP, microinjection of AngII (0.8 mmol/L; 60 nL) produced a depressor response, while the microinjection of 1.6 mmol/L (60 nL) AngII produced a pressor response. 5. Losartan blocked the increases in SAP induced by AngII in the VLM and DM. Decreases in SAP induced by AngII in the CVLM, however, were only slightly decreased by losartan. 6. Our data suggest that a significant portion of pressor and depressor sites of the pontomedulla contain neurons responsive to both AngII and Glu. In neurons in the VLM and DM, AngII produced pressor responses that were primarily mediated through AT₁ receptors, while the depressor actions of AngII in the CVLM were not mediated by AT₁ receptors.     

SCHISTOSOMIASIS VACCINATION HISTORICAL DEVELOPMENT, PRESENT STATUS AND FUTURE PROSPECTS*

50 years of research on killed or live vaccine for schistosomiasis without successful produc- tion of a human schistosomiasis vaccine are reviewed.     

Economic grand rounds: Income inequality and depression prevalence across the United States: an ecological study

Research has shown a relationship between income inequality and poor health. This column reports findings from a state-level study of the relationship between income inequality and the prevalence of depression. Estimates of depression prevalence by state, obtained from the Behavioral Risk Factor Surveillance System, were linked with Gini coefficients for U.S. household income, obtained from the Census Bureau. The current prevalence of depression was significantly associated with income inequality--the more unequal, the higher the depression prevalence. The association persisted after adjustment for income per capita, percentage of the population with a college degree, and percentage over age 65 years.     

Parathyroid hormone suppression by intravenous 1,25-dihydroxyvitamin D. A role for increased sensitivity to calcium.

Numerous in vitro studies in experimental animals have demonstrated a direct suppressive effect of 1,25-dihydroxyvitamin D (1,25(OH)2D) on parathyroid hormone (PTH) synthesis. We therefore sought to determine whether such an effect could be demonstrated in uremic patients undergoing maneuvers designed to avoid changes in serum calcium concentrations. In addition, the response of the parathyroid gland in patients undergoing hypercalcemic suppression (protocol I) and hypocalcemic stimulation (protocol II) before and after 2 wk of intravenous 1,25(OH)2D was evaluated. In those enlisted in protocol I, PTH values fell from 375 +/- 66 to 294 +/- 50 pg (P less than 0.01) after 1,25(OH)2D administration. During hypercalcemic suppression, the "set point" (PTH max + PTH min/2) for PTH suppression by calcium fell from 5.24 +/- 0.14 to 5.06 +/- 0.15 mg/dl (P less than 0.05) with 1,25(OH)2D. A similar decline in PTH levels after giving intravenous 1,25(OH)2D was noted in protocol II patients. During hypocalcemic stimulation, the parathyroid response was attenuated by 1,25(OH)2D. We conclude that intravenous 1,25(OH)2D directly suppresses PTH secretion in uremic patients. This suppression, in part, appears to be due to increased sensitivity of the gland to ambient calcium levels.