Oxazaphosphorine cytostatics: past-present-future. Seventh Cain Memorial Award lecture

The development of the oxazaphosphorine cytostatics cyclophosphamide, ifosfamide, and trofosfamide was based on the idea of applying the transport form/active form principle to the highly reactive nitrogen mustard group. A critical analysis and synopsis of the available results and knowledge will include examination of the extent to which the hypotheses on which this concept is based have been confirmed by experimental and clinical findings: 1. Chemical synthesis succeeded in converting the reactive nitrogen mustard into an inactive transport form (latentiation). 2. The requirement that the transport form be enzymatically activated to the active form in the target organ (the cancer cell) has been achieved by a sequence of metabolic reactions. 3. The aim of considerably increasing the therapeutic index of alkylating agents has been achieved by the oxazaphosphorine cytostatics. The greater cancerotoxic selectivity is closely correlated with the cytotoxic specificity of their activated primary metabolites. 4. The cancerotoxic selectivity of oxazaphosphorines was further increased when mesna was introduced as a regional uroprotector. Mesna eliminates the risk of therapy-limiting urotoxic side effects of oxazaphosphorines. With mesna protection, these cytostatics can be given in higher doses with increased safety, and their therapeutic efficacy can be enhanced. 5. Stabilization of the primary oxazaphosphorines, e.g., by attaching 2-mercaptoethanesulfonic acid (mafosfamide), opens up new possibilities in preclinical investigations and in therapy, e.g., for the clonogenic stem cell assay, for in vitro purging in autologous bone marrow transplantation, for regional perfusion of tumors, and, in small doses, for immunomodulation, where appropriate, in conjunction with "biological response modifiers."     

P67L: a cystic fibrosis allele with mild effects found at high frequency in the Scottish population.

Only three mutant cystic fibrosis (CF) alleles have to date been established as conferring a dominant mild effect on affected subjects who are compound heterozygotes. We now add a fourth, P67L, which occurs on about 1.4% of Scottish CF chromosomes. Among 13 patients (12 unrelated) with this allele, the average age at diagnosis was 22.5 +/- 11.3 years. None of the cases had consistently raised sweat chloride concentrations, the average value being 57 +/- 9 mmol/l; 77% of the patients were pancreatic sufficient. When compared to three other established mild CF alleles, R117H, A455E, and 3849 + 10kb C-T, a compound heterozygote for P67L has minimal disease and clinical suspicions are unlikely to be confirmed other than by DNA typing.     

5q — syndrome in a child

A boy aged 8 years, 10 months presented with refractory anemia. Bone marrow investigation revealed monolobular megakaryocytes. Cytogenetic analysis showed a clonal abnormality: 46, XY, del(5)(q14q32). This is the youngest individual ever reported with this disorder. A year after diagnosis, while on treatment with human recombinant erythropoietin, the bone marrow showed an excess of blasts. No bone marrow donor could be found. Transformation to acute myelomonocytic leukemia occurred 3 months later. In spite of intensive chemotherapy, the child died of progressive disease with massive splenomegaly and jaundice. The case illustrates that the 5q- syndrome can occur de novo in children. The outcome in this child was poor, which may reflect a difference from the adult 5q- syndrome or may possibly be related to the erythropoietin the child received.     

Successful treatment of chronic idiopathic urticaria and angioedema with cimetidine alone

We have studied a 50-year-old white man with chronic urticaria and angioedema who has responded to treatment with cimetidine alone for over 2 yr. In a double-blind, placebo-controlled study, cimetidine alone was at least as effective as chlorpheniramine in relief of urticaria and angioedema. Additionally, cimetidine significantly inhibited (p less than 0.01) the wheal response to histamine when it was compared to placebo. The inhibition of wheal response to histamine by cimetidine was significantly higher (p less than 0.05) than chlorpheniramine. The presence of predominantly H2- rather than H1-histamine receptors in the cutaneous blood vessels may be responsible for the therapeutic effects of cimetidine in this patient.     

Physicians' weight loss counseling in two public hospital primary care clinics.

PURPOSE: Primary care physicians are an important source of information on weight management. Nevertheless, weight loss counseling by these physicians remains inadequate. This study sought to determine physicians' barriers to providing weight loss counseling in a public hospital, patients' recall of physicians' weight loss recommendations, and the influence of physicians' counseling on patients' understanding, motivation, and behavior regarding weight loss. METHOD: In 2001, four focus groups of faculty and residents were held at two primary care clinics affiliated with the Louisiana State University Health Sciences Center-Shreveport to determine the barriers to providing weight loss counseling. Scripted probes were used to uncover consensus norms. In 2001-02, structured exit interviews were conducted with 210 overweight or obese patients recruited from the clinics to determine patients' recall of physicians' weight loss recommendations, and patients' understanding of the relationship between weight and health, and their stages of readiness for weight loss. RESULTS: Physicians identified major barriers to providing weight loss counseling, including insufficient confidence, knowledge, and skills. Obesity was underdocumented as a distinct clinical diagnosis. Only 5% of the patients recalled being given the combined weight loss strategy of diet and exercise. However, patients who recalled being counseled to lose weight were more likely to understand the risks of obesity, the benefits of weight loss, and were at a higher stage of readiness for weight loss. CONCLUSIONS: Physicians' weight loss counseling had a significant effect on patients' understanding of and motivation for weight loss. However, physicians provided insufficient guidance on weight management strategies, possibly because of inadequate counseling skills and confidence.