Carcinoma of the maxillary antrum — A 10 year experience

A retrospective analysis was performed of 250 cases of carcinoma of the maxillary antrum seen over a 10 years period (1975–1984). 98.24% patients were seen in T3 and T4 stages (UICC 1985). 40.7% patients presented with clinically palpable nodes. 42.9% patients were treated by radical radiation and 18.6% by a combination of preoperative radiation followed by surgery. Rest 38.5% patients were treated with palliative intention. Three year disease free survival was 39.58% with radiation alone and 51.91% with combined modality treatment which includes patients salvaged by surgery. Failures were mainly at the local site, 75.86% with radiation alone and 60% with combined modality treatment. Combined modality treatment, preferably preoperative radiation followed by radical surgery, gives the best results in the management of carcinoma of the maxillary antrum. Based upon paper read at 8th Congress of Association of Radiation Oncologists of India, Bombay, December 5–8, 1986.     

An observer study for direct comparison of clinical efficacy of electronic to film portal images

: To directly compare clinical efficacy of electronic to film portal images.

: An observer study was designed to compare clinical efficacy of electronic to film portal images acquired using a liquid matrix ion-chamber electronic portal imaging device and a conventional metal screen-film system. Both images were acquired simultaneously for each treatment port and the electronic portal images were printed on gray-level thermal paper. Four radiation oncologists served as observers and evaluated a total ot 44 sets of images for four different treatment sites: lung, pelvis, brain, and head/neck. Each set of images included a simulation image, a double-exposure portal film, and video paper prints of electronic portal images. Eight to nine anatomical landmarks were selected from each treatment site. Each observer was asked to rate each landmark in terms of its clinical visibility and to rate the ease of making the pertinent verification decision in the corresponding electronic and film portal images with the aid of the simulation image.

Resultings for the vesibility of landmarks and for the verification decision of treatment ports were similar for electronic and film images for most landmarks. However, vertebral bodies and several landmarks in the pelvis suchs as the acetabulum and pubic symphsis were more visible in the portal film images than in the electronic portal images.

The visibility of landmarks in electronic portal images is comparable to that in film portal images. Verification of treatment ports based only on electronic portal images acquired using an electronic portal imaging device is generally achievable.     

Mitochondrial electron transport chain complexes in aging rat brain and lymphocytes

Several lines of evidence suggest thatmitochondria not only plays a key role in thecausation of aging, but it is also the mostadversely affected organelle during aging. Theaim of the present study was to examine therole of mitochondria in the aging process bydetermining whether the activities of various`electron transport chain' (ETC) complexes aredeleteriously affected during aging in the ratbrain and lymphocytes. The enzyme activity ofETC complexes I–V, and citrate synthase (CS)were assayed from discrete brain areas viz.,cerebral hemisphere (CH), cerebellum (CB),brain stem (BS) and diencephalon (DC), along withthe lymphocytes from four different age groups ofrats, namely, 1-month-old rats, 3–4-month-oldadults, 12-month-old adults and24-month-old aged rats. Significant decline wasobserved in all the enzyme activities in 12 and24-month-old rats as compared to 3–4-month-oldadult rats. Moreover, one-month-old ratsshowed lower levels of ETC complexes ascompared to three to four-month-old rats. Lymphocytes anddiscrete brain areas showed a parallel patternof age-related alterations in the mitochondrialETC complexes and CS. The analysis of suchalterations is important in determining theultimate basis of neuronal dysfunctionassociated with aging, and defining thenature of these changes may also help to developtherapeutic means to cure not only the elderly butalso individuals suffering from certain organicor psychiatric disorders.     

Bone morphogenetic proteins: relevance in spine surgery

Bone morphogenetic proteins (BMPs) are low molecular weight glycoproteins that play a vital role in the development and maturation of skeletal tissue. Bone morphogenetic protein-induced mesenchymal cell recruitment and differentiation leads to the formation of chondroblasts and osteoblasts leading to the formation of de novo bone. Overwhelming pre-clinical and clinical evidence has suggested a promising role for BMPs for anterior and posterolateral spinal fusion. Strength of this approach lies in the potential ability of these growth factors to reverse inhibitory conditions common in the clinical setting and enabling predictable fusion. However, several issues related to carriers, costs, and dosages still need to be consecutively addressed. Gene therapy techniques producing in vivo osteoinductive factors and utilizing minimally invasive approaches are attractive options being developed for the future.     

Fusion of the CH1 domain of IgG1 to epidermal growth factor (EGF) prolongs its retention in the blood but does not increase tumor uptake

An expression vector (pJW4) for a human epidermal growth factor (hEGF)-CH1 fusion protein was constructed by fusing the gene for hEGF with the gene for CH1 of murine IgG1 with/without a peptide linker sequence [(GGGGS)3] and inserting the recombinant gene into vector pGEX2T. Expression vector pGEX2T was transfected into E. coli (BL-21) and hEGF-CH1 expressed by induction of the lac Iq promotor with 50 microM isopropyl beta-D-thiogalactopyranoside (IPTG). hEGF- CH1 fused to glutathione S-transferase (GST) was isolated and purified by affinity chromatography. GST was cleaved using thrombin. SDS-PAGE demonstrated a protein with the expected M(r) (18 kDa) positive for hEGF by Western blot. hEGF-linker-CH1 exhibited preserved binding to A431 (2-3 x 10(6) EGFR/cell) and MDA-MB-468 breast cancer cells (1-2 x 10(6) EGFR/cell). hEGF-CH1 without the linker exhibited poor receptor binding. hEGF-linker-CH1 also exhibited strong binding to soluble EGFR equivalent to that of hEGF. The tumor and normal tissue distribution of hEGF-linker-CH1 labeled with 123I was compared with 123 I-hEGF at 24 h after i.v. injection to mice implanted with s.c. MDA-MB-468 xenografts. Fusion of hEGF with CH1 increased its retention in the blood 14-fold but did not significantly increase tumor uptake. Tumor/blood ratios were higher for hEGF than for hEGF-linker-CH1. We conclude that hEGF is more attractive than hEGF-linker-CH1 for imaging EGFR-positive tumors.     

Insulin,insulin-like growth factor-I (IGF-I), IGF binding proteins,their biologic interactions,and colorectal cancer

Secular changes and worldwide variations in incidence rates of colorectal cancer, along with results from twin and migrant studies, provide compelling evidence that environmental factors influence the risk of this disease. Among the most important of these factors are diet and associated factors, such as physical activity and body size. Recent data suggest that dietary and related factors may influence colorectal cancer risk via their effects on serum insulin concentrations and on the bioavailability of insulin-like growth factor-I (IGF-I). Epidemiologic studies have shown that IGF-I is positively associated with the risk of colorectal cancer, and experimental studies have shown that IGF-I has mitogenic and antiapoptotic actions on colorectal cancer cells. IGF-I bioactivity is regulated in part by its six binding proteins (IGFBP-1 to IGFBP-6); insulin inhibits the production of IGFBP-1 and perhaps IGFBP-2. As a result, chronically elevated fasting and postprandial insulin levels may lead to a decrease in circulating IGFBP-1 and IGFBP-2 concentrations and, consequently, an increase in IGF-I bioavailability. Insulin may also increase the circulating IGF-I/IGFBP-3 ratio by increasing hepatic growth hormone sensitivity. The increased IGF-I bioavailability may, over time, increase the risk of colorectal cancer. This new evidence for biologic interactions among insulin, IGF-I, and IGFBPs in the context of colorectal carcinogenesis provides a potential mechanism through which diet and associated factors may increase the risk of this cancer.