Mutations in the gene encoding the Pit-1 transcriptional activator interfere with the embryologic determination and ultimate functions of anterior pituitary cells that produce growth hormone (GH), prolactin (Prl) and thyroid-stimulating hormone (TSH). Central hypothyroidism is often the presenting feature of combined pituitary hormone deficiency (CPHD), but it is not detected in screening programs that rely upon elevation of TSH. We report a child whose hypothyroidism was recognized clinically at age 6 weeks, and subsequently found to have GH and Prl as well as TSH deficiency. With thyroxine and GH replacement he has reached the 70th percentile for height and has normal intelligence. Molecular analysis of genomic DNA for Pit-1 revealed the presence of compound heterozygous recessive mutations: a nonsense mutation in codon 172 and a novel missense mutation substituting glycine for glutamate at codon 174. This case is the first demonstration of CPHD due to compound heterozygous Pit-1 point mutations, as most reported cases of the CPHD phenotype involve either the dominant negative R271W allele or homozygosity for recessive Pit-1 mutations. Therefore, in cases of CPHD, the possibilities of compound heterozygosity for two different Pit-1 mutations, or homozygosity for mutations in the epigenetic gene, Prop-1, should be considered.
We studied a 14 year-old girl with extreme short stature (-9.5 SDS), normal psychomotor development and signs of progressive hypothyroidism. Basal IGF-I and T4 were low. Serum GH was low after insulin-induced hypoglycemia and GH-releasing hormone administration. Both TSH and prolactin were low and did not rise after TRH administration. Gonadotropins were normal and cortisol levels were elevated. In contrast, DHEA-S levels were low and she did not develop pubic hair until 26 years of age, compatible with deficiency of a putative pituitary adrenal androgen stimulating hormone. Pituitary size was reduced on magnetic resonance imaging. Sequencing of the Pit-1 gene revealed a heterozygous C to T transition in codon 271 resulting in substitution of tryptophane for a highly conserved arginine. Her parents were homozygous normal for this locus indicating a de novo mutation with dominant expression. Genetic and phenotypic heterogeneity of patients with Pit-1 gene mutations, particularly the R271W mutation, may reveal further information about the nature of genetic silencing, imprinting, and epigenetic inheritance. The relationship of Pit-1 deficiency to abnormal adrenal secretion remains to be elucidated.
In this review we summarize the causes of cancer related thrombosis as well as modern treatment approaches. Malignancy as a risk factor for thromboembolism is becoming increasingly recognized by clinicians caring for these patients. The probability of thrombosis occurring in an individual patient is dependent on several factors, including accompanying medical problems, the type of cancer, the clinical stage, performance status, and the treatment modalities employed. Thrombophilia with a history of thromboembolism is important as well. The overall risk of thrombosis is sevenfold that of noncancer patients. Though much has been learned about the pathogenesis of cancer-related thrombosis, we are in fact just beginning to understand the cross-talk between cancer cells and their related microenvironment, and such investigations are likely to increase our knowledge of cancer-related thrombosis mechanisms. Research in these areas may also suggest new strategies for cancer prevention, metastasis suppression, and new treatments. Drugs used in cancer therapy are increasingly recognized to directly contribute to the thrombotic tendency. Few studies provide data on the optimal management of cancer patients with thrombosis. It has been learned that retreating with the same drug can be very hazardous. In general the approach to prevention of thrombosis is the same as for noncancer patients, recognizing that specific cancer types and stage can place a patient in a high-risk category. Initial coumadin therapy fails in a significant number of patients with cancer. Recognition of the cancer patients at highest risk for coumadin failure is challenging. Low-molecular-weight heparins appear to be more effective in such situations where coumadin is likely to fail or has failed, but these drugs are thought to be costlier. Newer agents such as Factor Xa inhibitors and TF inhibitors are currently under investigation and may be found useful in the management of cancer-related thrombosis.
Polyclonal anti-thymocyte globulin (ATG) reduces the risk for primary graft rejection as well as acute graft-versus-host disease (GVHD) by depleting T cells in both the host and the infused allograft. However, the impact of ATG on late outcomes is less certain. We report the results of a retrospective landmark analysis of consecutive patients who underwent an unrelated donor bone marrow transplant at our center between January 2001 and October 2005 (n=45) and survived at least 90 days following transplant. We compared late outcomes in patients who either recieved ATG (n=25) or did not (n=20) as a part of their conditioning regimen. Conditioning was with either busulfan and cyclophosphamide (n= 28; 17 without ATG) or BCNU, etoposide, cytarabine, and melphalan (n=18; 3 without ATG). Most patients (20) received rabbit ATG at a median dose of 3 mg/kg (range: 1.5–9 mg/kg) on day -4 and -3. Others were given equine ATG. GVHD prophylaxis consisted of tacrolimus + methotrexate in both groups. Median age was 42 years (range 18–65; 14 female). Bone marrow from unrelated donors matched at HLA-A, B, C, and DRB1 (7/8 and 8/8 matches) was used as the stem cell source. Diseases treated were CML (11), HD (9), AML (8), MDS (6), NHL (3), MM (3), and other (5). A median of 3 prior therapies had been given before transplant (range 1–5). There was no significant difference (Pearson χ2) in the number of patients beyond CR1/CP1 (n=25) and those having failed a prior autograft (n=17) between the two groups. The median overall survival in the recipients of ATG was 1382 days (95% CI: 373– 2391 days) as opposed to 364 days (95% CI: 0–851) in those not receiving ATG (P=0.125 by Log-Rank test); with a 1-year overall survival of 76% (59%–93%) vs. 50% (28–72) in the ATG vs. no ATG cohorts respectively, and 69% (49–89) vs. 44% (22–66) at 2-years. The 1-year progression free survival was 84% (69–98) vs.90% (77–100) in the ATG vs. no ATG cohorts, and 84% (69–98) vs. 67% (37–97) at 2 years. Chronic GVHD developed in 15/20 (75%) patients not receiving ATG (45% extensive), and in 12/25 (48%) in those recieving ATG (16% extensive) (P=0.06 Pearson χ2). Graft rejection was seen in 2/20 patients in the non-ATG arm and 1/25 patients in the ATG arm. Despite a lower incidence of chronic GVHD, the relapse rate was similar in the two groups (16% in the ATG group vs. 20% in the non-ATG group; P=0.73). Lymphoid recovery was similar in the two groups. The absolute lymphocyte counts at day-90 and day-180 post transplant were 680 vs 800/microL and 1100 vs. 1500/microL in the no ATG vs. ATG cohorts (P=0.275 repeated measures ANOVA). Serious late infections requiring parenteral antimicrobial treatment occured in 8 patients (32%) receiving ATG, and in 9 patients (45%) in the non-ATG arm ((P=0.248). CMV reactivation was seen in 8 patients (32%) receiving ATG, and 7 (35%) in the non-ATG arm. Eleven patients (55%) have died in the no ATG cohort from either relapse (2), GVHD (4) or infection (5); whereas in the ATG cohort 9 (36%) have died of either relapse (4), GVHD (3) or infection (2). In conclusion, ATG appears to reduce delayed transplant related complications, such as chronic GVHD and infections, in patients receiving bone marrow from unrelated donors. This may lead to a favorable trend towards improved survival in patients recieving ATG as a part of non-total body irradiation based conditioning.
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