Telomere length dynamics in normal individuals and in patients with hematopoietic stem cell-associated disorders

The telomere length in nucleated peripheral blood (PB) cells indirectly reflects the mitotic history of their precursors: the hematopoietic stem cells (HSCs). The average length of telomeres in PB leukocytes can be measured using fluorescence in situ hybridization and flow cytometry (flow FISH). We previously used flow FISH to characterize the age-related turnover of HSCs in healthy individuals. In this review, we describe results of recent flow FISH studies in patients with selected hematopoietic stem cell-associated disorders: chronic myelogenous leukemia (CML) and several bone marrow failure syndromes. CML is characterized by a marked expansion of myeloid Philadelphia chromosome positive (Ph+) cells. Nevertheless, nonmalignant (Ph-) HSCs typically coexist in the bone marrow of CML patients. We analyzed the telomere length in > 150 peripheral blood leukocytes (PBLs) and bone marrow samples of patients with CML as well as samples of Ph- T-lymphocytes. Compared to normal controls, the overall telomere fluorescence in PBLs of patients with CML was significantly reduced. However, no telomere shortening was observed in Ph- T-lymphocytes. Patients in late chronic phase (CP) had significantly shorter telomeres than those assessed earlier in CP. Our data suggest that progressive telomere shortening is correlated with disease progression in CML. Within the group of patients with bone marrow failure syndromes, we only found significantly shortened telomeres (compared to age-adjusted controls) in granulocytes from patients with aplastic anemia (AA). Strikingly, the telomere length in granulocytes from AA patients who had recovered after immunosuppressive therapy (recAA) did not differ significantly from controls, whereas untreated patients and nonresponders with persistent severe pancytopenia (sAANR) showed marked and significant telomere shortening compared to healthy donors and patients with recAA. Furthermore, an inverse correlation between age-adjusted telomere length and peripheral blood counts was found in support of a model in which the degree of cytopenia and the amount of telomere shortening are correlated. These results support the concept of extensive proliferation of HSCs in subgroups of AA patients and suggest a potential use of telomere-length measurements as a prognostic tool in this group of disorders as well.

Comparison of spiral CT angiography with conventional digital subtraction angiography in the evaluation of renal transplant donors: a pilot study

Conventional digital subtraction renal arteriography (IA-DSA) has been traditionally used as the preoperative imaging modality for assessment of renal vascular anatomy for renal transplant donors. This study evaluates the potential use of spiral CT angiography in replacing IA-DSA in the preoperative assessment of this group of patients. Seven patients underwent both spiral CT angiography and IA-DSA between October 1997 and April 1998. It is concluded that spiral CT angiography can demonstrate the number, length and location of renal arteries and it is suggested that spiral CT angiography can potentially replace IA-DSA in the preoperative assessment of renal donors.

Intracranial aneurysms: evaluation in 200 patients with spiral CT angiography

The goal of this study was to assess the usefulness of spiral CT angiography (CTA) with three- dimensional reconstructions in defining intracranial aneurysms, particularly around the Circle of Willis. Two hundred consecutive patients with angiographic and/or surgical correlation were studied between 1993 and 1998, with CTA performed on a GE HiSpeed unit and Windows workstation. The following clinical situations were evaluated: conventional CT suspicion of an aneurysm; follow-up of treated aneurysm remnants or of untreated aneurysms; subarachnoid haemorrhage (SAH) and negative angiography; family or past aneurysm history; and for improved definition of aneurysm anatomy. Spiral CTA detected 140 of 144 aneurysms, and an overall sensitivity of 97%, including 30 of 32 aneurysms 3 mm or less in size. In 38 patients with SAH and negative angiography, CTA found six of the seven aneurysms finally diagnosed. There was no significant artefact in 17 of 23 patients (74%) with clips. The specificity of CTA was 86% with 8 false-positive cases. Spiral CTA is very useful in demonstrating intracranial aneurysms.

HIV seroconversion during pregnancy and risk for mother-to-infant transmission

Pregnant women infected with HIV-1 were enrolled in a prospective mother-to-infant transmission study from 1992 through 1994 in Bangkok. In participating hospitals, voluntary HIV testing was routinely offered at the beginning of antenatal care and again in the middle of the third trimester of pregnancy. Women who seroconverted to HIV during pregnancy were compared with women who had tested positive on their first antenatal test. Maternal HIV RNA levels were determined during pregnancy, at delivery, and postpartum using RNA polymerase chain reaction (PCR), and infection status in infants was determined by DNA PCR. No infants were breast-fed, but prophylactic antiretroviral therapy was not yet used in Thailand to prevent transmission from mother to infant. Among enrolled women, 16 who seroconverted during pregnancy and 279 who were HIV-1-seropositive at their first antenatal test gave birth. Median plasma RNA levels at delivery were similar for the two groups (17,505 and 20,845 copies/ml, respectively; p =.8). Two (13.3%) of 15 infants born to women who seroconverted and 66 (24.8%) of 266 infants born to previously HIV-seropositive women were infected with HIV (p =.5). There was no increased risk for mother-to-infant HIV transmission and no significant difference in viral load at delivery between HIV-infected women who seroconverted to HIV during pregnancy and those who were HIV-seropositive when first tested.

The pre-hospital experiences of Samoan families who have had a child admitted to hospital with pneumonia: a qualitative investigation

AIMS

The aims of this investigation were to describe the pre-hospital experiences; health actions and attitudes towards health services of Samoan families who have had a child hospitalised with pneumonia. This information will inform policy makers, health professionals and the Samoan community in order for them to improve and create health care services that are appropriate for Samoan families.

METHOD

Twelve Samoan families, each with a child admitted to the Starship Children's Hospital with pneumonia, were interviewed in an open-ended in-depth interview style. Interviews lasted thirty to forty-five minutes and were undertaken in the preferred language of the caregiver (English or Samoan).

RESULTS

For most caregivers continuity of care in the community was poor. Reasons for this included structural and personal barriers to health care services and mistrust of doctors. Mistrust influenced caregivers to go elsewhere for care and therefore care became fragmented. The theory of delayed presentation was not supported. Caregivers were quick to act on symptoms and behaviours that they believed were different from normal and worse than non-urgent symptoms. Those who 'self-referred' to the hospital had in fact visited a doctor in the community at least once prior to admission. They had then made their own decision to present to the hospital. Reasons for self-referral included mistrust of health professionals in the community and structural and personal barriers to services. A break down in communication between caregivers and health professionals was an important personal barrier to services. Caregivers did not feel that pneumonia was an appropriate illness to be treated solely with traditional methods. Caregivers who consulted traditional practitioners had also consulted at least one doctor in the community.

CONCLUSION

Although Pacific children are less likely than other children to present to the emergency department with the documentation from a general practitioner, in many cases they have been to see one. A lack of continuity of care was caused by a break down in communication between the caregiver and the health professional rather than there being an inability by caregivers to recognise the symptoms of pneumonia and therefore a delay in presentation. This breakdown in communication could be one explanation for the differences in illness severity and hospitalisation for pneumonia among children in different ethnic groups. Considering their reasons for doing so, caregivers who self-referred attended the emergency department appropriately. The use of traditional health methods did not impair access to Western medicine for these children with pneumonia.

Oral oseltamivir treatment of influenza in children

BACKGROUND

Oral oseltamivir administration is effective treatment for influenza in adults. This study was conducted to determine the efficacy, safety and tolerability of oseltamivir in children with influenza.

METHODS

In this randomized, double blind, placebo-controlled study, children 1 through 12 years with fever [> or =100 degrees F (> or =38 degrees C)] and a history of cough or coryza <48 h duration received oseltamivir 2 mg/kg/dose or placebo twice daily for 5 days. The primary efficacy endpoint was the time to resolution of illness including mild/absent cough and coryza mild/absent, return to normal activity and euthermia.

RESULTS

Of 695 enrolled children 452 (65%) had influenza (placebo, n = 235; oseltamivir, n = 217). Among infected children the median duration of illness was reduced by 36 h (26%) in oseltamivir compared with placebo recipients (101 h; 95% confidence interval, 89 to 118 vs. 137 h; 95% confidence interval, 125 to 150; P < 0.0001). Oseltamivir treatment also reduced cough, coryza and duration of fever. New diagnoses of otitis media were reduced by 44% (12% vs. 21%). The incidence of physician-prescribed antibiotics was significantly lower in influenza-infected oseltamivir (68 of 217, 31%) than placebo (97 of 235, 41%; P = 0.03) recipients. Oseltamivir therapy was generally well-tolerated, although associated with an excess frequency of emesis (5.8%). Discontinuation because of adverse events was low in both groups (1.8% with oseltamivir vs. 1.1% with placebo). Oseltamivir treatment did not affect the influenza-specific antibody response.

CONCLUSIONS

Oral oseltamivir administration is an efficacious and well-tolerated therapy for influenza in children when given within 48 h of onset of illness.

Safety of late in utero exposure to zidovudine in infants born to human immunodeficiency virus-infected mothers: Bangkok. Bangkok Collaborative Perinatal HIV Transmission Study Group

BACKGROUND

Short-course zidovudine (ZDV) given in the late antenatal period can reduce mother-infant human immunodeficiency virus (HIV) transmission by one half. Because this intervention is being implemented in developing countries, evidence of its safety is needed.

METHODS

In a randomized, double-blinded, placebo-controlled trial in Bangkok, HIV-infected pregnant women received either ZDV (300 mg twice daily from 36 weeks' gestation until labor, then every 3 hours until delivery) or an identical placebo regimen. Infants were evaluated at birth and at 1, 2, 4, 6, 9, 12, 15, and 18 months of age. Growth, clinical events, and hematologic and immunologic measurements were compared between treatment groups.

RESULTS

Of the 395 children born (196 in ZDV group and 199 in placebo group), 330 were uninfected, 55 were infected, and 10 had indeterminate infection status. Overall, 319 children (81%) completed 18 months of follow-up, and 14 (4%) died before 18 months of age. Among uninfected children, the mean hematocrit was lower in the ZDV group at birth (49.1% vs 51.5%) but not at later ages; mean weight, height, head circumference, and CD4(+) and CD8(+) T lymphocyte counts were similar in both groups at all ages. Five uninfected children in the ZDV group but only one in the placebo group had a febrile convulsion. No other signs suggestive of mitochondrial dysfunction and no tumors were observed. Among infected children, an estimated 62% in the ZDV group and 77% in the placebo group survived free of Centers for Disease Control and Prevention class C disease during the 18-month follow-up.

CONCLUSIONS

No significant adverse events were associated with short-course ZDV during 18 months of follow-up in this population.

Protease inhibitors stimulate hematopoiesis and decrease apoptosis and ICE expression in CD34(+) cells

Highly active retroviral therapy has been associated with a decline in the frequency of cytopenia in patients with human immunodeficiency virus (HIV) infection. This may result from lower hematologic toxicity of newer antiviral drugs and their increased efficacy against HIV-1. Protease inhibitors, in addition to their effects on HIV replication, appear to affect various cellular functions. Recently, it was reported that ritonavir inhibited caspase-1 expression in normal CD4(+) cells. It was hypothesized that protease inhibitors may improve hematopoietic function owing to their direct effects on the bone marrow progenitor cells. When ritonavir was added to methylcellulose cultures of bone marrow cells from HIV-infected patients and normal controls, colony formation increased 2.4-fold (n = 5) in control cultures and 4-fold (n = 5) in cultures of cells from HIV-infected patients. In the presence of ritonavir, cultures of CD34(+) cells showed markedly decreased apoptosis in comparison with untreated cultures (45% decrease in apoptotic cell number; n = 6). A synthetic inhibitor of caspase 1 (Ac-Tyr-Val-Ala-Asp-aldehyde [single-letter amino acid codes]), which inhibits activation of several caspases including CPP32 and interleukin 1beta-converting enzyme (ICE or caspase 1), also decreased the rate of apoptosis and enhanced colony formation by progenitor cells derived from HIV-infected patients (3-fold; n = 5). In ritonavir-treated samples derived from HIV-infected individuals, the number of cells expressing ICE also decreased. In conclusion, HIV protease inhibitors may, by blocking the caspase-dependent apoptotic pathway, overcome inhibition of hematopoiesis seen in patients with HIV infection, an effect unrelated to their antiviral activity. (Blood. 2000;96:2735-2739)

A comparison of full-length glycoprotein 120 from incident HIV type 1 subtype E and B infections in Bangkok injecting drug users with prototype E and B strains that are components of a candidate vaccine

Complete gp120 sequence information was obtained from eight persons with incident HIV-1 infections (four subtype E and four subtype B) who were part of a prospective injecting drug user (IDU) cohort in Bangkok, Thailand, during 1996-1998. The incident subtype E strains were similar to the prototype subtype E strain CM244 isolated in 1992 in northern Thailand. The incident subtype B strains displayed divergence, in both overall genetic distance and other significant gp120 characteristics, from the prototype North American subtype B strain HIV-MN. Recombinant gp120s derived from CM244 and HIV-MN strains are components of a vaccine that is undergoing phase III efficacy testing, begun in March 1999, among Bangkok area IDUs. The information presented here will be important in the evaluation of any breakthrough HIV-1 infections occurring among vaccinees during the vaccine trial and in ongoing vaccine development efforts in Thailand.

Sequence variants of the axin gene in breast, colon, and other cancers: an analysis of mutations that interfere with GSK3 binding

Axin is a recently discovered component of a multiprotein complex containing APC, beta-catenin, GSK3, and PP2A, which functions in the degradation of the beta-catenin protein. As part of WNT signal transduction, the function of the Axin complex is inhibited, leading to the accumulation of beta-catenin. The inappropriate stabilization of beta-catenin has been implicated in a range of human tumors. Two oncogenic mechanisms leading to beta-catenin stabilization are the loss of the APC tumor suppressor protein and the mutational activation of beta-catenin, such that the Axin/APC complex can no longer regulate it. Studies in Drosophila and mammalian tissue culture showed loss of Axin function interfered with beta-catenin turnover and activated beta-catenin/TCF-dependent transcription. Based on these observations, Axin was screened for mutations in a range of human tumor cell lines and primary breast tumor samples. We identified two sequence variants causing amino acid substitutions in four colon cancer cell lines, a Ser-to-Leu at residue 215 in LS513 and a Leu-to-Met at residue 396 in HCT-8, HCT-15, and DLD-1. The Axin L396M mutation was selected for further study since it lay within a region that was shown to interact with glycogen synthase kinase-3. Biochemical and functional studies showed that the L396M change interfered with Axin's ability to bind GSK3. Interestingly, this mutation and a neighboring L392M change differentially altered Axin's ability to interfere with two upstream activators of TCF-dependent transcription, Frat1 and Disheveled.

Early experience in the use of Levovist ultrasound contrast in the evaluation of liver masses

The aim of the present paper was to assess the utility of Levovist in defining the pathology of liver masses. Levovist is a new ultrasound contrast agent consisting of galactose microparticles, air bubbles and palmitic acid. Prospective studies were performed in patients referred for further evaluation of known liver masses. Levovist was peripherally injected and colour Doppler ultrasound studies were performed. Findings were correlated with clinicopathology and three other imaging modalities: biphasic spiral CT, CT arterial portography and contrast MRI. Twenty-five patients were studied (15 male and 10 female) in the age range 25-74 years. Liver masses ranged from 0.5 to 7 cm in maximum diameter. Thirteen lesions were benign and 12 were malignant (four hepatomas (HCC) and eight metastases). Levovist enhancement occurred in 18 lesions. Of these, six were benign (four focal nodular hyperplasias (FNH) and two haemangiomas). All 12 malignant lesions demonstrated enhancement. The HCC showed a mosaic pattern of central and peripheral enhancement, and the FNH demonstrated a spoke-wheel pattern. It was not possible to distinguish between haemangiomas and malignant lesions. Non-enhancing lesions may well be benign, with all malignancies showing some enhancement. Characteristic enhancement patterns were found for HCC (mosaic) and FNH (spoke-wheel). It was not possible to distinguish between metastases and benign lesions (haemangiomas) when the pattern of enhancement was peripheral.

Disability evaluation in children with hemidecorticectomy: use of the activity scales for kids and the pediatric evaluation disability inventory

The purpose of this study is to investigate the level of disability of children who are either candidates for or have undergone a hemidecorticectomy. The Activity Scales for Kids and the Pediatric Evaluation Disability Inventory were demonstrated to be useful measurement tools yielding comparative results between subgroups. Overall, children with congenital disease seemed less autonomous postoperatively than were preoperative patients or children with acquired disease. Age at surgery and the interval between seizure onset and surgery are potentially important predictors of disability. This could reflect the importance of timing of surgery, development, environment, and possibly brain plasticity processes in this population.

Cytokine-mediated bone resorption is cytochrome P-450 dependent. Student Research Award 1998

Localized bone loss leads to much of the morbidity of chronic otitis media. Although the cellular events of bone remodeling have been well established, their regulation remains poorly understood. Various cytokines, including tumor necrosis factor-alpha, interleukin-1beta, and interferon-gamma, used alone and in combination, are powerful inducers of bone resorption. One of the modulators of cytokine-induced bone resorption is nitric oxide (NO), a product of the action of NO synthase (NOS) on L -arginine to form NO. Cytochrome P-450, an enzyme that is similar to NOS both structurally and functionally, may also have a role in NO production in various cellular systems. The goal of this study was to elucidate a possible role of cytochrome P-450 in bone. In this study cytokine-induced bone resorption was blocked with cimetidine and clotrimazole, which are selective inhibitors of the cytochrome P-450 IIIA family and 7-ethoxyresorufin, a nonspecific cytochrome P-450 inhibitor. A concomitant reduction of NO was also observed. This effect may be explained by cytochrome P-450 being a preferred alternative pathway or providing an essential cofactor to NOS in bone.

Clinical disease associated with HIV-1 subtype B' and E infection among 2104 patients in Thailand

BACKGROUND

Two HIV-1 envelope subtypes have accounted for virtually all infections in Thailand: subtype B' (Thai B), found mainly in injection drug users (IDU), and subtype E, found in over 90% of sexually infected persons and an increasing proportion of IDU in recent years. It remains unclear whether there are differences in pathogenesis associated with these HIV-1 subtypes.

METHODS

From November 1993 to June 1996, demographic, risk, clinical, and laboratory data were collected by enhanced surveillance from HIV-infected inpatients (> or =14 years) at an infectious disease hospital near Bangkok. HIV-1 subtype was determined by V3-loop peptide enzyme immunoassay (EIA). Because of confounding, multivariate analyses were stratified by risk category and controlled for sex and age.

RESULTS

The infecting HIV-1 subtype was determined for 2104 (94.9%) of 2217 HIV-infected patients with complete data: 284 (13.5%) were subtype B', 1820 (86.5%) were E. Specimens from 113 (5.1%) patients were non-reactive or dually reactive on peptide EIA and were excluded. Among IDU, 199 (67.2%) had subtype B', and 97 (32.7%) had E. IDU accounted for 70.1% (199/284) of patients with subtype B' and 5.3% (97/1820) of those with E. Patients infected with HIV-1 subtypes B' or E had similar spectrums of opportunistic infections (OI), levels of immunosuppression, and in-hospital mortality rates. Of patients who did not inject drugs, more patients infected with subtype E had extrapulmonary cryptococcosis than those with subtype B' (adjusted odds ratio, 2.6; 95% confidence interval, 1.28-5.37).

CONCLUSION

HIV-1 subtypes B' and E seem to be associated with similar degrees of immunosuppression and, with one exception, with similar OI patterns. These data do not suggest an association between HIV-1 subtype and differences in pathogenicity.

Case report: inappropriate use of percutaneous drainage in the management of pancreatic necrosis

We describe three cases of severe necrotizing pancreatitis, with Apache II scores of 11, 17 and 22, respectively. There was no significant pancreatic parenchymal perfusion in any of the three patients on contrast-enhanced computed tomography. All three patients were primarily treated with percutaneous drains and all three subsequently required open laparotomies. We do not recommend percutaneous drainage as a definitive therapy for severe necrotizing pancreatitis.

Use of a metallic stent for relief of symptoms caused by superior vena caval obstruction in a patient with advanced cancer: a case report

This report describes the insertion of a metallic stent in the superior vena cava to relieve the symptoms of malignant superior vena caval obstruction in a 75-year-old woman with far-advanced lung cancer in whom other methods of symptom control had been ineffective. Her symptoms were quickly relieved by insertion of the stent. She died 1 month following the procedure, without recurrence of the symptoms. The technical aspects of the procedure and the issues affecting the clinical decision-making process in this case are discussed.

Pitfalls in the use of spiral CT for identification of intracranial aneurysms

We describe problems encountered in our first 136 patients, with 95 aneurysms, who underwent spiral CT for investigation of possible aneurysms involving the circle of Willis and adjacent major vessels, and who had surgical and/or angiographic confirmation. There were seven false-positive cases, of which the first three could be explained by operator inexperience. There were four false negatives, all small aneurysms; two were not seen because of operator error and two were hidden by an adjacent larger aneurysm. Clip artefacts prevented diagnostic studies in six of 21 postoperative studies. One aneurysm was outside the CT field of view, being on a pericallosal artery. One basilar artery tip aneurysm was excluded from the field of the CT study because of a planning error. Inspection of the axial source images is critical if the diagnosis of small or thrombosed aneurysms is to be made. Close attention to image acquisition and computer modelling is required to reduce errors in spiral CT angiography of intracranial aneurysms.

Spiral CT scanning in the detection and evaluation of aneurysms of the Circle of Willis

PURPOSE

To assess the utility of spiral computed tomography (CT) with three-dimensional reconstruction in defining aneurysms of the Circle of Willis.

METHODS

Eighty-one patients with angiographic or surgical correlation were studied between 1993 and 1995, with surface rendered reconstructions of the arteries of the Circle of Willis.

RESULTS

Spiral CT was useful in six clinical situations: further assessment in cases with CT suspicion of an aneurysm, follow-up of known untreated aneurysms or aneurysm remnants, subarachnoid hemorrhage (SAH) with negative angiography, a past or family history of aneurysms, and improved definition of aneurysm anatomy. Ten of fifteen patients with previous surgery had no significant artifacts on the spiral study. In 66 other patients studied in search of aneurysms, the sensitivity of detection was 95% and specificity 74%. Seventeen of nineteen aneurysms 3 mm or less in size and 38 of 39 larger were detected by spiral CT. Four of thirteen patients with SAH and previous negative angiography had aneurysms identified, which were confirmed at surgery.

CONCLUSIONS

There is great promise in the use of spiral CT in demonstrating aneurysms of the Circle of Willis, including very small ones. Careful detailing of scan protocols and meticulous examination of multiplanar images are needed for maximum accuracy.

Bone mass during growth: the effects of exercise. Exercise and mineral accrual

Intense exercise during childhood and adolescence may result in primary amenorrhea and low peak bone mineral density (BMD). After puberty, exercise may result in secondary amenorrhea and bone loss. Higher BMD in amenorrheic athletes than amenorrheic sedentary persons suggests that exercise may partly offsets the effects of amenorrhea. To examine this possibility, we measured BMD (g/cm2) by dual x-ray absorptiometry in 32 ballet dancer and 23 healthy controls of comparable age with regular menstrual cycles, 34 pre-pubertal female gymnasts bone age 8.9 +/- 0.2 years and 37 girls matched by bone age. Dancers had normal BMD at the weight bearing sites, not low, despite having oligomenorrhea, not high despite 32 hours of week dancing. BMD was lower by 4-6 percent at the non-weight bearing sites. BMD diminished in the dancers at the weight bearing femoral neck (r = -0.29, P = 0.1) and trochanter (r = -0.31, P = 0.09), and at the non-weight bearing arms (r = -0.29, P = 0.09) with increasing duration of amenorrhea. Dancers with less than 40 months amenorrhea had 5 to 7% higher BMD at the weight bearing, but not non-weight bearing sites. Dancers with more than 40 months amenorrhea had normal, not higher BMD at weight bearing sites and deficits of about 5 percent at non-weight bearing sites. In gymnasts, BMD was 10-15 percent (or 1 SD) higher than the bone age-predicted mean. Exercise may not offset the effects of amenorrhea. Bone loss may continue but from a higher level, perhaps attained prior puberty.