Maternal methylation imprints on human chromosome 15 are established during or after fertilization.

Prader-Willi syndrome (PWS) is a neurogenetic disorder that results from the lack of transcripts expressed from the paternal copy of the imprinted chromosomal region 15q11-q13 (refs. 1,2). In some patients, this is associated with a deletion of the SNURF-SNRPN exon 1 region inherited from the paternal grandmother and the presence of a maternal imprint on the paternal chromosome. Assuming that imprints are reset in the germ line, we and others have suggested that this region constitutes part of the 15q imprinting center (IC) and is important for the maternal to paternal imprint switch in the male germ line. Here we report that sperm DNA from two males with an IC deletion had a normal paternal methylation pattern along 15q11-q13. Similar findings were made in a mouse model. Our results indicate that the incorrect maternal methylation imprint in IC deletion patients is established de novo after fertilization. Moreover, we found that CpG-rich regions in SNURF-SNRPN and NDN, which in somatic tissues are methylated on the maternal allele, are hypomethylated in unfertilized human oocytes. Our results indicate that the normal maternal methylation imprints in 15q11-q13 also are established during or after fertilization.

The haematologist as watchdog of community health by full blood count.

Although full blood counts (FBC) are among the most commonly performed laboratory tests, the contribution of routine FBCs to the diagnosis of new problems is controversial. This study represents a unique linkage of a consultant haematology team, reviewing all abnormal blood counts, to an organization providing ambulatory health care to 350,000 patients. The objective was to establish the underlying clinical disorders responsible for all abnormal FBCs during a 2-month period, and to estimate the impact of the haematology team on the diagnostic work-up and management of newly identified problems. 572 (2.55%) of the 22,454 FBCs were abnormal. Of these, 357 showed microcytosis, caused by iron deficiency (58%), thalassaemia minor (35%), inflammation (6%) or chronic renal failure (1%). The most common causes of normocytic anaemia (25 patients) were disseminated malignancy and acute blood loss; of macrocytosis (27 patients), chronic liver disease and cancer; of erythrocytosis (16 patients), chronic hypoxia; of thrombocytopaenia (48 patients), chronic liver disease and ITP; of thrombocytosis (47 patients), iron deficiency and inflammation; of leukopaenia or pancytopaenia (20 patients), cirrhosis and disseminated malignancy; and of leukocytosis (26 patients), chronic leukaemias in the elderly and infection in children. Major new haematological abnormalities were encountered in 0.24% of all blood counts, representing about one new diagnosis per day. Routine blood counts do contribute to the health care of a population. Screening for haematological disease through a central clinical laboratory covering a large high-risk ambulatory population offers a cost-effective way of searching for serious clinical problems, alerting the primary physicians of their existence, and offering advice in continued evaluation and problem management.

Clinical implications of fluorescence in situ hybridization analysis in 13 chronic myeloid leukemia cases: Ph-negative and variant Ph-positive.

Thirteen chronic myeloid leukemia (CML) patients, 10 with variant Philadelphia (Ph) translocations and 3 Ph negative cases, were analyzed by fluorescence in situ hybridization (FISH) with the use of BCR and ABL cosmid probes and a chromosome 22 painting probe. In the variant Ph translocations, the BCR-ABL fusion gene was located on the Ph chromosome; in 1 CML Ph-negative patient, the BCR-ABL fusion gene was located on the Ph chromosome; and, in 2 patients, it was located on chromosome 9. The chromosome 22 painting probe was detected on the third-party chromosome of the variant translocation, and in none of the variant translocations was there any detectable signal on chromosome 9. In CML patients with clonal evolution of a simple Ph, a signal of the chromosome 22 painting probe was detected on the der(9) of the Ph translocation. It was concluded that the variant Ph translocations evolved simultaneously in a three-way rearrangement. The clinical parameters of the 13 patients were similar to those of a large group of CML patients with a simple Ph translocation. It is suggested that, to determine the prognosis of CML patients with a complex karyotype, FISH analysis with a chromosome 22 painting probe be performed.

Diagnostic value of the D-dimer test in deep vein thrombosis: improved results by a new assay method and by using discriminate levels.

Previous studies have suggested that D-dimer testing reliably selects patients for whom duplex sonography should be performed for diagnosis of deep vein thrombosis (DVT). However, the interassay correlation is poor. Therefore, we tested four D-dimer methods for their ability to rule out DVT, including the Miniquant test, a new D-dimer assay method. Sensitivity, specificity, negative predictive value (NPV) and positive predictive value (PPV) were calculated vs. duplex sonography. Twenty-nine of 108 (27%) patients with suspected DVT were diagnosed as having DVT by sonography. The Vidas enzyme-linked immunoabsorbent assay (ELISA) test, the Miniquant turbidimetric test and the latex agglutination test for D-dimer all provided discriminate values for achieving 100% sensitivity and 100% NPV. D-dimer results demonstrated higher specificity and PPV in the outpatient vs. the inpatient group. This probably reflects the higher proportion of inpatients with comorbid conditions, such as malignancy and postsurgery status, in whom D-dimer results show very poor specificity and PPV. The new Miniquant turbidimetric assay performed as well as the more established ELISA method. We conclude that the D-dimer tests were shown to possess the necessary sensitivity and NPV to be useful in screening patients with suspected DVT. A negative D-dimer test in selected patients could be helpful in reducing the number of sonograms performed for diagnosis of DVT.

Mycotic aneurysm of the external carotid artery.

Mycotic aneurysms of the extracranial carotid arteries are extremely rare. A case is reported of an external carotid artery aneurysm that developed in a patient with infective endocarditis. We review 15 previously reported cases of mycotic aneurysms of the cervical carotid arteries, one of which occurred in a patient with infective endocarditis. None of them occurred in the external carotid artery. Most cases were due to local trauma, a contiguous focus of infection or bacteremia. Surgical resection and appropriate antibiotic treatment lead to cure in most cases.

Gold-induced lung disease.

A 70-year-old female with seronegative rheumatoid arthritis developed interstitial pneumonitis while on chrysotherapy. The reversibility of lung disease and favourable response to steroid treatment support the diagnosis of gold-induced lung disease and distinguish this entity from other forms of interstitial lung disease associated with rheumatoid arthritis. The relevant literature related to gold-induced lung disease is briefly reviewed.

Use of danazol in the management of chronic idiopathic thrombocytopenic purpura.

Danazol, an impeded androgen, was used for treating three patients with chronic idiopathic thrombocytopenic purpura (ITP) refractory to corticosteroid therapy. Sustained remission was achieved in one of the three cases. A temporary response was obtained in the second patient. In the last case, platelet count improved, but the patient died of severe interstitial pneumonitis. These observations confirm recent reports on the efficacy of danazol in the management of ITP and indicate that danazol treatment improves platelet counts in the majority of patients with refractory ITP, and in some cases may obviate the need for splenectomy.

Hodgkin's disease of the skin. A case report.

A 74 year-old woman presented with cutaneous Hodgkin's disease and local bone involvement. Both were secondary to regional lymph flow obstruction by lymph nodes massively involved by nodular sclerosing Hodgkin's disease. Though a temporary remission was achieved by combination chemotherapy, skin lesions were quick to reappear in spite of continued treatment. This was felt to be due to local mechanical factors. A review of the literature reveals two main patterns of Hodgkin's disease of the skin. In one, the disease is either confined to the skin, or is unrelated to existing nodal or visceral involvement. In the other, skin infiltration is secondary to regional lymph node involvement by Hodgkin's disease, as seen in our patient. The pattern of skin involvement by Hodgkin's disease should be taken into consideration in assessing its prognostic significance.

Adaptive design improvements in the continual reassessment method for phase I studies.

The continual reassessment method (CRM) enables full and efficient use of all data and prior information available in a phase I study. However, despite a number of recent enhancements to the method, its acceptance in actual clinical practice has been hampered by several practical difficulties. In this paper, we consider several further refinements in the context of phase I oncology trials. In particular, we allow the trial to stop when the width of the posterior 95 per cent probability interval for the maximum tolerated dose (MTD) becomes sufficiently narrow (that is, when the information accumulating from the trial data reaches a prespecified level). We employ a simulation study to evaluate five such stopping rules under three alternative states of prior knowledge regarding the MTD (accurate, too low and too high). Our results suggest our adaptive designs preserve the CRM's estimation ability while offering the possibility of earlier stopping of the trial.

Gastrin-producing ovarian cystadenocarcinoma: sensitivity to secretin and SMS 201-995.

We report a patient with severe peptic ulcer disease and a right ovarian mass that was found to be a gastrin-producing cystadenocarcinoma. Gastrin production by the tumor was stimulated by secretin and inhibited by the long-acting somatostatin analogue SMS 201-995. Following resection of the tumor, serum gastrin levels and the gastrin response to secretin returned to normal. Histologic examination, including Alcian blue staining for mucin and immunoperoxidase staining for gastrin, revealed gastrin at the base and mucin at the apex of the tumor cells. This report demonstrates secretin stimulation and somatostatin inhibition of gastrin secretion from a cell that is apparently not of endocrine origin.

Immunoglobulin E levels following allogeneic, autologous, and syngeneic bone marrow transplantation: an indirect association between hyperproduction and acute graft-v-host disease in allogeneic BMT.

Markedly elevated serum IgE levels have been noted following allogeneic bone marrow transplantation (BMT) and have been correlated with graft-v-host disease (GVHD) in several studies. To investigate this phenomenon, we measured serum IgE levels in 387 allogeneic, 143 autologous, and 21 syngeneic BMT recipients before and at intervals after BMT. As a population, allogeneic BMT recipients displayed a biphasic elevation in IgE levels, with peak levels occurring either early (days 15 to 19) or late (days 80 to 89) posttransplant. Only in individuals in whom peak levels occurred early did IgE level correlate with liver disease, histological changes, and overall clinical stage of GVHD. The association of IgE elevation and GVHD does not appear to be direct since recipients of syngeneic (monozygotic twin) grafts had the highest incidence of IgE hyperresponsiveness as well as the highest absolute IgE levels. Similarly, 22 recipients of autologous marrow not treated with 4-hydroperoxycyclophosphamide had elevated IgE levels comparable to those seen in allogeneic graft recipients. We hypothesize that augmented IgE synthesis and its subsequent resolution is the natural consequence of immune reconstitution in the presence of potentially reaginic agents such as antibiotics and infectious agents. As such, IgE hyperresponsiveness in syngeneic graft recipients may reflect the maturational sequence of IgE regulatory elements in the absence of interference by GVHD, GVHD therapy, or minor histocompatibility disparities. The cell populations required for IgE response (T cells, B cells, and antigen-presenting cells) may be reconstituted in advance of the regulatory elements that limit IgE production in healthy subjects. Although this temporal relationship does not appear to hold in allogeneic BMT, the balance between positive and negative factors, which determines the rates of IgE synthesis and catabolism, may be altered by GVHD, infection, and liver dysfunction acting alone or in combination.