The tree-in-bud pattern is commonly seen at thin-section computed tomography (CT) of the lungs. It consists of small centrilobular nodules of soft-tissue attenuation connected to multiple branching linear structures of similar caliber that originate from a single stalk. Originally reported in cases of endobronchial spread of Mycobacterium tuberculosis, this pattern is now recognized as a CT manifestation of many diverse entities. These entities include peripheral airway diseases such as infection (bacterial, fungal, viral, or parasitic), congenital disorders, idiopathic disorders (obliterative bronchiolitis, panbronchiolitis), aspiration or inhalation of foreign substances, immunologic disorders, and connective tissue disorders and peripheral pulmonary vascular diseases such as neoplastic pulmonary emboli. Knowledge of the many causes of this pattern can be useful in preventing diagnostic errors. In addition, although the causes of this pattern are frequently indistinguishable at radiologic evaluation, the presence of additional radiologic findings, along with the history and clinical presentation, can often be useful in suggesting the appropriate diagnosis.

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Bisphosphonates (BPs) are the most widely used drugs to treat osteoporosis. However, recent reports associated to long-term BPs use with atypical low-impact fractures and prodromal pain. It is estimated that 26% of the cases of atypical fractures associated with the long-term use of BPs show delayed healing or nonunion. Teriparatide [PTH1-34] (TPTD) is an anabolic drug shown to be effective in stimulating bone formation. The aim was to describe the course of a right diaphyseal femoral fracture sustained by a patient on long-term BPs treatment. A 57-year-old postmenopausal Caucasian female presented with delayed healing of a right femoral diaphyseal fracture 10 months after the fracture, despite having received orthopedic treatment. The fracture was preceded by progressive, severe, and bilateral thigh pain. Her medical history included osteopenia that was treated with alendronate over 7 years. On presentation at our clinic, the patient ambulated with the aid of a walking cane. The diagnosis was an atypical right femoral fracture associated with long-term alendronate use. The levels of the following parameters were measured: mineral metabolism laboratory: intact parathormone, 40 ng/mL (reference values (rv): 10-65 ng/mL); 25-hydroxyvitamin D, 40 ng/mL (rv: >30 ng/mL); serum Crosslaps, 318 ng/mL (rv: 80-590 ng/mL); and bone-specific alkaline phosphatase, 76UI/L (rv: 31-95UI/L)]. Magnetic resonance imaging of the left femur was performed, which revealed a diaphyseal stress fracture. She was prescribed 20 µg/day of subcutaneous (s.c.) TPTD (PTH1-34, Forteo; Eli Lilly Co., Indianapolis, IN, United States). A computed tomography scan performed 3 months later showed that the fracture had healed; the patient was able to resume her usual activities. Twenty micrograms per day of s.c. TPD accelerated the healing of the atypical fracture associated with long-term alendronate therapy, allowing a fast recovery of ambulation and quality of life.

Objective: To evaluate the changes of the biochemical parameters of mineral metabolism and to assess the effect of these changes on the bone mass of young healthy men who voluntarily lived in the Antarctic Continent for one year. Design: Lumbar spine and whole body bone mineral density (BMD) were measured pre-and post-campaign (14 months later). Serum and urinary biochemical parameters were measured every two months. Serum levels of calcium, phosphate, total alkaline phosphatase, parathormone (PTH) and 25-hydroxyvitamin D (250HD) were determined in blood fasting samples; and hydroxyproline, calcium and creatinine in 2 h fasting urine. The subjects received a dose of 100 IUad of vitamin D during May after obtaining the samples and then an average of 125 IUad from July to January. Subjects: Seventeen healthy volunteers, who left Buenos Aires during the 1992 summer: ten arrived in the Belgrano II Base at the end of January and the other seven arrived in San Martõ Ân in March and stayed there up to summer 1993. Results: BMD increased in lumbar spine (L2±L4), total body and the subarea of the legs but there were no differences between the pre-and post-campaign values in arms and pelvis. The percentage of fat mass decreased signi®cantly after 1 y of residence in Antarctica, in comparison to the basal values. Most biochemical parameters remained unaltered and within the normal range during the whole study. PTH showed a nadir in March (end of the summer) when compared to initial levels (73.0 AE28.2 vs 39.9 AE32.7 pgaml, P`0.05), and recovered its initial value in spring. Calcium levels showed a signi®cant decrease in March (9.5 AE0.4 vs 8.5 AE1.0 mg%, P`0.01). 25OHD levels began to decrease in March (24.7 AE6.4 vs 18.7 AE5.3 ngaml), reaching a minimum value whose difference approached statistical signi®cance during the winter period (July: 16.4 AE8.2 ml, 0.05`P`0.06). No signi®cant changes in serum phosphate, total alkaline phosphatase, urinary hydroxyprolineacreatinine and calciumacreatinine ratios were found through the year. Conclusions: 25OHD levels decreased in autumn and winter (nadir in July) and recovered the initial levels by the end of the campaign. An unexplained marked diminution in PTH and serum calcium was found at the beginning of the campaign. In spite of the low vitamin D levels, bone mass in this group of young healthy men increased, probably because of their intense physical activity.

We examined genetic diversity of howler monkeys (Alouatta palliata) from Costa Rica. Blood samples of howler monkeys were collected at various locations in Costa Rica, and electrophoresis of total plasma proteins yielded no variation. We also conducted starch gel electrophoresis of red cell isozymes and did not find variation for any of the 14 loci analyzed (i.e., ACP, ADA, CA2, EST, GPI, IDH, LDH-1, LDH-2, MDH, PGD, PGM-1, PGM-2, SOD, and TPI). These findings were compared with the levels of genetic variation for A. seniculus and A. belzebul from one Brazilian population. Four of the 14 isozymes (ADA, GPI, PGD, and SOD) showed more than one allele for these species. Both A. seniculus and A. belzebul from Brazil showed similar levels of genetic variation. The potential causes of the low genetic variation in A. palliata from Costa Rica are discussed.