Vitamin D

Vitamin D evolved for the development and maintenance of a healthy vertebrate skeleton. Vitamin D (1,25-dihydroxyvitamin D) maintains serum calcium and phosphorus levels in a physiologic range for skeleton mineralization. Vitamin D increases intestinal calcium absorption, stimulating osteoblast function and mobilizing osteoclast precursor cells to enhance bone calcium mobilization. Most vitamin D for the human requirement comes from exposure to sunlight. Sunscreen use, aging, and an increase in latitude or skin pigmentation dramatically reduce the cutaneous synthesis of vitamin D₃. Vitamin D deficiency has been linked to increased risk of many chronic diseases, including diabetes, cancer, hypertension, and heart disease. There is strong evidence that vitamin D plays a role in immunomodulation, cellular proliferative activity regulation, and renin production downregulation. Thus, vigilance to prevent vitamin D deficiency by the measurement of serum 25-hydroxyvitamin D is important for overall health and well-being. Although the recommended adequate intake for vitamin D is 200, 400, and 600 international units (IUs) for ages 0–50, 51–70, and 71+ yr, respectively, in the absence of exposure to adequate sunlight, the requirement is at least 1000 IUs of vitamin D. Responsible sun exposure will guarantee vitamin D sufficiency. Eating and drinking foods fortified with vitamin D, such as milk and orange juice, also provides some of the vitamin D requirement.     

Homozygous D

A homozygote for the Rh complex .D. associated with the rare Evans antigen was identified and her family tested: .D./.D. can be clearly distinguished serologically from -D-/-D-. The immune antibody in the serum of the propositus reacts with all cells tested except homozygous -D-, CwD-, cD- and Rhnull cells.     

Hepatitis D

Opinion statement The hepatitis delta virus (HDV) is a defective RNA virus that requires the help of hepatitis B virus (HBV) for virion assembly and penetration into hepatocytes. Thus, it can only cause disease in individuals who carry HBV. HDV infection is present worldwide, predominantly in tropical and subtropical areas. However, with increased HBV control, HDV infection has significantly declined, although stably persisting, in developed countries. Most HDV-infected individuals develop chronic hepatitis D, and in approximately 80% of those cases, chronic hepatitis D progresses to cirrhosis within 5 to 10 years. The only approved therapy for chronic hepatitis D is interferon-α. Although transplantation offers a safe therapeutic option for managing end-stage HDV disease, novel therapeutic approaches are urgently needed.     

What is the optimum A-V interval in D.D.D. pacing?

One of the programmable parameters in recent pacemakers is atrio-ventricular interval. To find out the optimum A-V interval studies were done in 14 patients. Multigated radionuclide scans were used to measure the left ventricular function, at a resting heart rate of 70/minute. Seven patients had poor left ventricles (ejection fraction less than 50%). Left ventricular ejection fraction, relative cardiac output and end diastolic counts were highest at 250 M. Sec. interval compared to 150. Ejection rates and end systolic counts were not related to A-V interval. Relative cardiac output was 27% higher in poor ventricles at 250 delay than 150. This observation was not significant in normal hearts. Optimum P-R interval is 250 M. Sec. for maximum left ventricular function.     

Volumetric CT scanning: 2D and 3D reconstruction

This review aims to present the 2D and 3D reconstructions derived from high-resolution volume CT acquisitions and to illustrate their thoracic applications, as well as showing the interest and limitations of these techniques. We present new applications for computer-assisted detection (CAD) and tools for quantification of pulmonary lesions.