Laparoscopic surgery in Crohn's disease

In a prospective study the feasibility and safety of laparoscopic-assisted ileocaecal resection for Crohn's disease was studied and compared with 16 patients who had open ileocaecal resection, and the value of laparoscopic stoma surgery was assessed. From January to November 1995 laparoscopic-assisted ileocaecal resection for Crohn's disease was undertaken in 7 patients, laparoscopic-assisted stoma formation in 10 patients. In 1 patient laparoscopic ileocaecal resection was converted to open surgery due to an unrecognised ileocolic fistula. Operating time in laparoscopic-assisted ileocaecal resections was longer than in open ileocaecal resection (150 vs. 127 min, P = 0.7). Blood loss (386 vs. 445 ml, P = 0.7), first bowel movement (3.5 vs. 4.9 postoperative days, P = 0.07) and postoperative time to discharge (5.2 vs. 9.9 days, P < 0.01) in patients who had a laparoscopic-assisted ileocaecal resection were less than in patients who had open surgery. In all 10 patients laparoscopic formation of a stoma was possible. Operating time was 62 min. Oral solids were restored on the 1.5 postoperative day. Mean postoperative stay was 8.8 days, prolonged due to time needed for stoma-care training. These preliminary results indicate that laparoscopic-assisted ileocaecal resection and stoma surgery for Crohn's disease are feasible and safe. Both procedures are characterised by rapid recovery and superior cosmetic results.     

Multiple nucleocapsid packaging of Autographa californica nucleopolyhedrovirus accelerates the onset of systemic infection in Trichoplusia ni

Among the nucleopolyhedroviruses (Baculoviridae), the occlusion-derived virus (ODV), which initiates infection in host insects, may contain only a single nucleocapsid per virion (the SNPVs) or one to many nucleocapsids per virion (the MNPVs), but the significance of this difference is unclear. To gain insight into the biological relevance of these different packaging strategies, we compared pathogenesis induced by ODV fractions enriched for multiple nucleocapsids (ODV-M) or single nucleocapsids (ODV-S) of Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) containing a beta-galactosidase reporter gene. In time course experiments wherein newly molted fourth-instar Trichoplusia ni were challenged with doses of ODV-S or ODV-M that yielded the same final mortality ( approximately 70%), we characterized viral foci as either being restricted to the midgut or involving tracheal cells (the secondary target tissue, indicative of systemic infection). We found that while the timing of primary infection by ODV-S and ODV-M was similar, ODV-S established significantly more primary midgut cell foci than ODV-M, but ODV-M infected tracheal cells at twice the rate of ODV-S. The more efficient establishment of tracheal infections by ODV-M decreased the probability that infections were lost by midgut cell sloughing, explaining why higher numbers of primary infections established by ODV-S within larvae were needed to achieve the same final mortality. These results showed that the multiple nucleocapsid packaging strategy of AcMNPV accelerates the onset of irreversible systemic infections and may indicate why MNPVs have wider individual host ranges than SNPVs.     

Contribution of a conserved asparagine to the conformational stability of ribonucleases Sa, Ba, and T1

The contribution of hydrogen bonding by peptide groups to the conformational stability of globular proteins was studied. One of the conserved residues in the microbial ribonuclease (RNase) family is an asparagine at position 39 in RNase Sa, 44 in RNase T1, and 58 in RNase Ba (barnase). The amide group of this asparagine is buried and forms two similar intramolecular hydrogen bonds with a neighboring peptide group to anchor a loop on the surface of all three proteins. Thus, it is a good model for the hydrogen bonding of peptide groups. When the conserved asparagine is replaced with alanine, the decrease in the stability of the mutant proteins is 2.2 (Sa), 1.8 (T1), and 2.7 (Ba) kcal/mol. When the conserved asparagine is replaced by aspartate, the stability of the mutant proteins decreases by 1.5 and 1.8 kcal/mol for RNases Sa and T1, respectively, but increases by 0.5 kcal/mol for RNase Ba. When the conserved asparagine was replaced by serine, the stability of the mutant proteins was decreased by 2.3 and 1.7 kcal/mol for RNases Sa and T1, respectively. The structure of the Asn 39 --> Ser mutant of RNase Sa was determined at 1.7 A resolution. There is a significant conformational change near the site of the mutation: (1) the side chain of Ser 39 is oriented differently than that of Asn 39 and forms hydrogen bonds with two conserved water molecules; (2) the peptide bond of Ser 42 changes conformation in the mutant so that the side chain forms three new intramolecular hydrogen bonds with the backbone to replace three hydrogen bonds to water molecules present in the wild-type structure; and (3) the loss of the anchoring hydrogen bonds makes the surface loop more flexible in the mutant than it is in wild-type RNase Sa. The results show that burial and hydrogen bonding of the conserved asparagine make a large contribution to microbial RNase stability and emphasize the importance of structural information in interpreting stability studies of mutant proteins.     

Human pregnancies after transfer of fresh (four- to eight-cell) versus frozen-thawed blastocysts resulting from intracytoplasmic sperm injection

PURPOSE: The objective of this study was to obtain expanded blastocysts following intracytoplasmic sperm injection (ICSI) and Vero-cell co-culture, cryopreserve them at this stage, and transfer the frozen-thawed blastocysts to obtain pregnancies. METHODS: Twenty-two couples with severe male-factor infertility or failed fertilization in a previous in vitro fertilization cycle were included in this study. ICSI was performed for all of them, and sperm-injected oocytes were immediately subjected to Vero-cell co-culture for varying intervals. Then 14 couples were treated by embryo transfer at the four- to eight-cell stage (Group I), whereas 8 couples were treated by transfer of frozen-thawed blastocysts (Group II). RESULTS: Percentages of cleaved embryos and term survival rates were 57.1 and 73.3% for Group I and 50.0 and 37.5% for Group II, respectively. CONCLUSIONS: Blastocysts obtained after ICSI and Vero-cell co-culture can retain developmental competence after cryopreservation and thawing. Transfer of frozen-thawed blastocysts derived by these means holds promise for establishment of viable pregnancies.     

Improvement in the prognosis of breast cancer from 1965 to 1984

PURPOSE: The prognosis of breast cancer has improved over the past three decades. It is uncertain, however, whether this improvement results from an increase in the cure rate, extension of the life span of uncured patients, or some combination. METHODS: From the Connecticut Tumor Registry, we obtained data on 25,091 patients with localized (node-negative) and regionally metastatic (node-positive) breast cancer who were diagnosed over the two decades between 1965 and 1984, with follow-up through 1993. The data for these patients were analyzed using a variety of parametric models to quantitate likelihood of cure and median survival time among uncured patients. These models incorporate the assumption that time to death from breast cancer follows a specific distribution. RESULTS: For patients with node-negative disease, parametric analysis revealed no significant difference in cured-fraction or median survival time over the two decades studied. For patients with node-positive disease, however, a significant increase in median survival time (P < .001) was found during the second decade (1970 to 1979). There was also a trend toward a higher cured-fraction over time, but this was not statistically significant. CONCLUSION: This study confirms that patients with node-positive disease had an improved prognosis over the two decades studied. Parametric analysis suggests that this improvement reflects primarily an increase in the median survival time for uncured patients, although there is a trend toward an increase in the likelihood of cure.