Effect of radiation dose on the development of mixed haemopoietic chimerism following T cell-depleted allogeneic bone marrow transplantation.

The presence of mixed haemopoietic chimerism (MXC) was evaluated by cytogenetic and molecular analysis in 48 patients undergoing T cell-depleted BMT. The dose of total body irradiation (TBI) prescribed to all patients (14.4 Gy) was calculated to compensate for the absence of T cells in the graft. The actual midline dose of TBI received, however, differed significantly depending on the method of TBI administration. Thus, 35 adult patients received an average midline dose of 14.3 Gy, while 13 children received a lower dose of 13 Gy. The incidence of MXC in the adult group, who had received very close to 14.4 Gy to the midline, was 34% (12/35), which is lower than in most reported T cell-depleted series. During follow-up, chimerism remained relatively stable with time but varied between haemopoietic lineages. There was no relationship with relapse. MXC in the 13 children who had received a lower midline TBI dose was significantly higher at 69% (9/13) (p < 0.05) and increased to 90% (9/10) if patients who received additional chemotherapy in their conditioning were excluded (p = 0.001). This suggests that, in terms of marrow ablation, relatively small changes in the dose of TBI may be biologically significant, at least at this dose range. Again, in the lower TBI group MXC was not predictive of relapse.     

Rapid tryptophan depletion improves decision-making cognition in healthy humans without affecting reversal learning or set shifting.

Rapid tryptophan (Trp) depletion (RTD) has been reported to cause deterioration in the quality of decision making and impaired reversal learning, while leaving attentional set shifting relatively unimpaired. These findings have been attributed to a more powerful neuromodulatory effect of reduced 5-HT on ventral prefrontal cortex (PFC) than on dorsolateral PFC. In view of the limited number of reports, the aim of this study was to independently replicate these findings using the same test paradigms. Healthy human subjects without a personal or family history of affective disorder were assessed using a computerized decision making/gambling task and the CANTAB ID/ED attentional set-shifting task under Trp-depleted (n=17; nine males and eight females) or control (n=15; seven males and eight females) conditions, in a double-blind, randomized, parallel-group design. There was no significant effect of RTD on set shifting, reversal learning, risk taking, impulsivity, or subjective mood. However, RTD significantly altered decision making such that depleted subjects chose the more likely of two possible outcomes significantly more often than controls. This is in direct contrast to the previous report that subjects chose the more likely outcome significantly less often following RTD. In the terminology of that report, our result may be interpreted as improvement in the quality of decision making following RTD. This contrast between studies highlights the variability in the cognitive effects of RTD between apparently similar groups of healthy subjects, and suggests the need for future RTD studies to control for a range of personality, family history, and genetic factors that may be associated with 5-HT function.     

MacIntosh-Jones reconstruction for the unstable knee

A group of 45 patients who underwent replacement of a ruptured anterior cruciate ligament with a free graft of one-third of the patellar tendon combined with a lateral extra-articular tenodesis have been reviewed. The average age of the patients was 26.4 years and the mean follow-up period 3.2 years. Stability was achieved in 42 patients (93 per cent), judged on clinical criteria. Overall patient satisfaction was high at 73 per cent and 38 patients (84 per cent) maintained their sporting activity at a social or competitive level. Those who had unsatisfactory results had undergone significant delay before anterior cruciate ligament reconstruction.     

Arthroscopic and endoscopic skills: a method of assessment.

An aptitude test has been designed to assess the psychomotor ability of surgeons under the special conditions and difficulties of endoscopic surgery. Results show increased errors and inferior tracking skill when images are rotated or reflected under test conditions simulating endoscopy. This indicates that more than simple hand-eye co-ordination is required to perform good endoscopic surgery. Interestingly, a proportion of trainee surgeons found adaptation to these altered conditions difficult to master. This aptitude test might usefully identify junior surgeons who would benefit from extra tuition at instructional endoscopic courses. The implications for the selection and training of surgeons are discussed.     

Insulin-like growth factors, insulin-like growth factor-binding proteins, and endometrial cancer in postmenopausal women: results from a U.S. case-control study.

OBJECTIVE: To assess whether circulating insulin-like growth factor-1 (IGF-1), IGF-2, insulin-like growth factor-binding protein-1 (IGFBP-1), or IGFBP-3 were associated with endometrial cancer in postmenopausal women. STUDY DESIGN: Between 1987 and 1990, we conducted a case-control study of 405 women with endometrial cancer and 297 matched population-based controls. This analysis included 174 postmenopausal cases and 136 controls. RESULTS: In logistic regression models adjusted for potential confounders, higher IGF-1 levels were not positively associated with endometrial cancer: odds ratio (OR) for the highest tertile versus the lowest tertile = 0.63, 95% confidence interval (CI) = 0.30-1.32. Endometrial cancer was inversely associated with IGF-2 (OR for the highest tertile = 0.35, 95% CI = 0.18-0.69) and IGFBP-3 (OR for the highest tertile = 0.40, 95% CI = 0.21-0.77), and not associated with IGFBP-1. CONCLUSION: Serum IGF-1, IGF-2, and IGFBP-3, but not IGFBP-1, were inversely associated with endometrial cancer in postmenopausal women. These associations and the potential role of the IGF system in endometrial proliferation and carcinogenesis warrant further research.     

The evolution of benign arterionephrosclerosis from age 6 to 70 years.

Arterionephrosclerosis is diagnosed at autopsy by assessing the severity and extent of certain structural features in the renal cortical arteries seen in tissue sections. These features are characterized by fibrotic intimal thickening and medial shrinkage, a progressive change from the youthful muscular pattern to the elderly sclerotic pattern. Intimal fibrosis can be quantified by expressing intimal thickness as a percentage of the arterial outer diameter (% OD). The magnitude of arterionephrosclerosis, found by averaging the measures of intimal fibrosis seen in a kidney, can be calculated from age and mean blood pressure, using a standard prediction function. This function is a quantitative statement of a fundamentally important principle: just as blood pressure is a continuous variable that can range from low to high levels, arterionephrosclerosis is also a continuous variable that can take any degree of abnormality of arterial structure from minimal to maximal. Furthermore, a correspondence exists between the two quantities so that each can be calculated from the other. In this study, a correlation of 0.966 was found between the observed and the calculated magnitudes of arterionephrosclerosis over 10-year age groups from 25 to 34 years to 65 to 74 years, using group average data within age groups. For individuals, however, the correlations between observed and calculated magnitudes of arterionephrosclerosis were about 0.6 in a former study of elderly subjects and about 0.1 in the subjects aged 6 to 27 years in this study. The average growth rate of arterionephrosclerosis was found to be about 0.25 %OD per year from ages 15 to 54 years, and about 0.13 %OD per year from ages 55 to 70 years; the growth rate did not increase in the oldest age groups when blood pressure averaged higher than blood pressure in more youthful subjects. These and other findings are consistent with the view that the reason a correlation exists between blood pressure and arterionephrosclerosis could be because the magnitude of arterionephrosclerosis is one of the determinants that sets the level of blood pressure. From this perspective, each individual can be viewed as having other determinants of blood pressure, methodologic or biologic, which add to or subtract from the values set by age and arterionephrosclerosis. When subjects are pooled into groups, so that individual determinants balance out, the group average levels of mean blood pressure could be interpreted as reflecting little other than the magnitude of arterionephrosclerosis at each specific age.