Telomerase activity and expression of telomerase subunits in the testicular tissue of infertile patients

OBJECTIVE

Determination of telomerase activity and the expression of human telomerase RNA (hTR) and human telomerase reverse transcriptase (hTERT) in the testicular tissue of patients with infertility arising from various causes.

DESIGN

Prospective observational study.

SETTING

A university hospital.

PATIENT(S)

Thirty-three patients with azoospermia arising from various causes. There were 12 testicular biopsy specimens from patients with Sertoli cell-only syndrome, 9 from patients with maturation arrest, and 12 from patients with obstructive azoospermia and normal histologic findings.

INTERVENTION(S)

Thirty-three testicular biopsies.

MAIN OUTCOME MEASURE(S)

Correlation of histologic findings at testicular biopsy with telomerase activity, hTERT, and hTR.

RESULT(S)

All 12 biopsy specimens from patients with obstructive azoospermia were positive for telomerase activity, hTR, and hTERT. Biopsy specimens from the 9 patients with maturation arrest were positive for telomerase activity in 8 cases, hTR in 9 cases, and hTERT in 5 cases. None of the patients with Sertoli cell-only syndrome showed either telomerase activity or hTERT, but all of them showed hTR.

CONCLUSION(S)

Telomerase activity and evidence of hTERT in testicular tissue are highly sensitive and highly specific markers of gametogenesis, which could gain in importance as part of the fertility workup before microinjection procedures.

Constitutive modelling of abdominal organs

Abdominal organs are very susceptible to trauma. In order to protect them properly against car crash and other impact consequences, we need to be able to simulate the abdominal organ deformation. Such simulation should account for proper stress-strain relation as well as stress dependence on strain rate. As the step in this direction, this paper presents three-dimensional, non-linear, viscoelastic constitutive models for liver and kidney tissue. The models have been constructed basing on in vivo experiments conducted in Highway Safety Research Institute and the Medical Centre of The University of Michigan (Melvin et al., 1973). The proposed models are valid for compressive nominal strains up to 35% and fast (impact) strain rates between 0.2 and 22.5 s(-1). Similar models can find applications in computer and robot assisted surgery, e.g. the realistic simulation of surgical procedures (including virtual reality) and non-rigid registration.

Efficacy and tolerability of tolterodine in children with detrusor hyperreflexia

OBJECTIVES

To investigate the urodynamic effects and tolerability of the new antimuscarinic drug tolterodine in children with detrusor hyperreflexia.

METHODS

Twenty-two children (12 boys and 10 girls; age range 3 months to 15 years, mean age 5.7 years) with detrusor hyperreflexia resulting in maximum detrusor pressures exceeding 40 cm H(2)O during filling cystotonometry were enrolled to receive tolterodine tartrate (a total of 0.1 mg/kg orally daily, divided into two doses) either as a first-line therapy (n = 12, group 1) or replacing oxybutynin chloride therapy (n = 10, group 2). Within 3 months, all patients underwent urodynamic re-evaluation during ongoing tolterodine treatment.

RESULTS

In group 1, the mean maximum bladder capacity increased from 120.2 to 173.0 mL (+44%), the mean detrusor compliance increased from 8.7 to 13.5 mL/cm H(2)O (+55%), and the mean maximum detrusor pressures decreased from 70.1 to 37.9 cm H(2)O (-46%); the differences were significant (P < 0.001). In group 2, no differences in the urodynamic effects of oxybutynin versus tolterodine were noted. Only 1 patient experienced a transient and moderately adverse effect with tolterodine.

CONCLUSIONS

Although based on a limited number of subjects, these data indicate that in pediatric patients with detrusor hyperreflexia, tolterodine may be better tolerated than and equally effective as the standard drug oxybutynin chloride.

Flow cytometric immunophenotypic characterization of pediatric and adult minimally differentiated acute myeloid leukemia (AML-M0)

We reviewed the clinicopathologic and immunophenotypic profiles of 7 pediatric and 11 adult minimally differentiated acute myelogenous leukemias (AML-M0). We also compared and evaluated myeloperoxidase in leukemic blasts using standard cytochemical and polyclonal antibody immunohistochemical stains. No distinctive clinical findings were noted in either patient group; however, thrombocytopenia typically was more prominent in adults. Adult AML-M0 also was associated with an immature myeloid profile (CD34+, terminal deoxynucleotidyl transferase positive, CD13+, and CD33+), in contrast with pediatric AML-M0, which usually lacked terminal deoxynucleotidyl transferase or CD34 but expressed bright CD33 with weak or negative CD13. Coexpression of the T-cell-associated antigen CD7 was observed in both groups. Antibody immunohistochemical stains were more sensitive than cytochemical stains for detection of myeloperoxidase activity and a useful adjunct for establishing a diagnosis of myeloid leukemia in paraffin-embedded marrow tissues.

Out-of-hospital intravenous cannulation: the perspective of patients treated by London Ambulance Service paramedics

OBJECTIVES

Previous research has highlighted concern about infection rates in field-placed intravenous (IV) cannulae. In a study of IV placement by London Ambulance Service (LAS) paramedics, 17% of placements were judged to be inappropriate. Large variations in rates of IV placement between LAS paramedics were found. The authors' hypothesis was that placement of an IV carries disadvantages-pain, discomfort, distress, and infection-which may be unacceptable to patients.

METHODS

This was a survey of all patients having an IV placed by LAS paramedics and transported to one of three London emergency departments (EDs) over a three-week period in December 1996. Patients were excluded if they had a self-inflicted injury/illness, were less than 14 years old, had no known address, or were visitors to the UK, or if their family doctor suggested it was not appropriate to contact the patient. Pain, discomfort, and distress; infection; satisfaction; understanding of the reason for cannulation; and out-of-hospital cannula use were all ascertained and analyzed with chi-square analysis.

RESULTS

Thirty-nine percent of the respondents experienced some discomfort, 39% some pain, and 17% some distress. No patient reported an infection. Distress was more likely to be reported if there was no understanding of why the IV cannula was placed (chi2 [1] 6.1; p < 0.05). Further unstructured information revealed satisfaction with the IV cannulation and with general care.

CONCLUSIONS

Despite the disadvantages of IV placement being reported by some respondents, overall levels of satisfaction were high, suggesting that these disadvantages were not unacceptable to patients. However, in the context of the 24,000 patients cannulated each year by LAS paramedics, "costs" to the patient are considerable.

Cardiovascular fitness in premenarcheal girls and young women

Maximal oxygen uptake (VO2max) in females, expressed as ml x kg(-1) x min(-1), declines steadily during the first three decades of life. The contribution of diminished cardiovascular function to this apparent fall in aerobic fitness is unknown. Cardiac responses to maximal cycle exercise were compared in 24 premenarcheal females (mean age 11.7 years) and 17 young adult women (mean age 27.4 years) using Doppler echocardiography. Mean VO2max was 40 ml x kg(-1) x min(-1) and 34.7 ml x kg(-1) x min(-1) in the girls and women, respectively (p < 0.05). When VO2max was expressed relative to allometrically-derived mass(0.52), however, no significant difference was observed in aerobic fitness between the two groups. Similar allometric analyses revealed no significant differences in average maximal cardiac output (10.50 vs 10.07 L x min(-1) BSA(-1.11) for girls and women, respectively) nor maximal stroke volume (53 vs 56 ml BSA(-1.13) respectively). These findings suggest that 1) allometric scaling is important in eliminating the effects of body size on VO2max, 2) body dimension differences can account for variations in VO2 in young females, and 3) cardiac functional reserve is similar in premenarcheal girls and young adult women.

Sodium detection during the water absorption response in Rana pipiens

Although taste in vertebrates is typically associated with specialized receptors in the lingual epithelium, Hoff and Hillyard reported that the toad, Bufo punctatus, is able to "taste" sodium with the abdominal skin. This was reflected in a differential behavioral response to hypertonic NaCl. The present study tests for the presence of such abdominal chemoreceptors in the frog Rana pipiens. The experiment was a five-condition design in which frogs were placed on filter paper saturated with: deionized water, 250 mM NaCl, 350 mM NaCl, 12.9 microM amiloride, or 350 mM NaCl + 12.9 microM amiloride. The time that the frogs remained on the test substrate before moving to a surface of deionized water was recorded. It was necessary to dehydrate the frogs to 80% of their body weight to elicit a behavioral response to the NaCl whereas dehydration to 90% of their body weight has been reported effective in Bufo punctatus. The frogs displayed significantly shorter mean times to move on both concentrations of NaCl compared to deionized water, with the shortest times occurring when 350 mM NaCl was used. Amiloride alone did not have an effect upon times to move to deionized water, but did significantly reduce the response to 350 mM NaCl. Movement to amiloride + 350 mM NaCl did not differ significantly from that to deionized water. The results indicate that Rana pipiens, like Bufo punctatus, have epithelial chemoreceptors for the detection of NaCl on hydrated surfaces and that these receptors, like those of mammals, are amiloride sensitive.

Biomechanics of soft tissues

Recent developments in Computer-Integrated and Robot-Aided Surgery (in particular, the emergence of automatic surgical tools and robots (as well as advances in Virtual Reality techniques, call for closer examination of the mechanical properties of very soft tissues (such as brain, liver, kidney, etc.). Moreover, internal organs are very susceptible to trauma. In order to protect them properly against car crash and other impact consequences we need to be able to predict the organ deformation. Such prediction can be achieved by proper mathematical modelling followed by a computer simulation. The ultimate goal of our research into the biomechanics of these tissues is development of corresponding, realistic mathematical models. This paper contains experimental results of in vitro, uniaxial, unconfined compression of swine brain tissue obtained by the author in Mechanical Engineering Laboratory, Japan, and discusses liver and kidney in vivo compression experiments conducted in Highway Safety Research Institute and the Medical Centre of The University of Michigan. The stress-strain curves for investigated tissues are concave upward for all compression rates containing no linear portion from which a meaningful elastic modulus might be determined. The tissue response stiffened as the loading speed increased, indicating a strong stress (strain rate dependence. As the step in the direction towards realistic computer simulation of injuries and surgical procedures, this paper presents two mathematical representations of brain, liver and kidney tissue stiffness. Biphasic and single-phase models are discussed. The biphasic model is shown to be inappropriate due to its inability to account for strong stress-strain relationship. Agreement between the proposed single-phase models and experiment is good for compression levels reaching 30% and for loading velocities varying over five orders of magnitude. Presented mathematical models can find applications in computer and robot assisted surgery, e.g. the realistic simulation of surgical procedures (including virtual reality), control systems of surgical robots, and non-rigid registration, as well as ergonomic design for injury prevention.

Effects of allocare-givers on fitness of infants and parents in callitrichid primates

The effects of callitrichid primate helpers (allocare-givers other than an infant's father) on the survival, reproduction or behavior of infants and parents are reviewed, using both published studies and data from free-ranging golden lion tamarins (Leontopithecus rosalia). Three lines of evidence suggest that helpers may increase their own inclusive fitness: (1) The number of adult males acting as helpers in free-ranging groups is correlated with the number of surviving infants in 3 callitrichid species. However, the lack of a negative correlation with number of infants dying suggests that activities other than direct infant care (e.g. territory defense) may be more important, especially in newly formed groups. (2) In 2 species, captive groups with helpers carry infants for longer periods of time than do groups without helpers. Whether such differences would translate into meaningful survival differences in free-ranging groups is unclear. (3) Helpers reduce the energetic burden of parents by reducing the amount of time they spend transporting or provisioning infants in at least 4 species. Reproductive males are more likely than reproductive females to benefit from the presence of helpers, reducing their investment in infant care activities as the number of helpers in the group increases. In free-ranging golden lion tamarins, the reproductive tenure of males, but not females, increases with the number of helpers in the group, suggesting that a reduction in energetic investment may translate into increased survival. 'Decisions' made by helpers to participate in infant transport are weighed against competing needs for foraging, vigilance, territory defense and, in some cases, prospecting for breeding opportunities. Given this complexity, a sophisticated model may be required to answer the question of how helpers 'decide' to participate in infant care versus other activities.

Renal cell carcinoma. Guidelines for diagnosis and treatment

Diagnosis of renal cell carcinoma (RCC) is established using sonography and confirmation by computed tomography (CT). Due to the widespread use of these imaging techniques for numerous indications, small renal tumors are increasingly detected by chance. As the sensitivity of CT is very high, treatment of RCC is routinely initiated without histological confirmation. Standard therapy of locally confined tumors without evidence of lymph node or hematogenic metastases is nephrectomy. However, the results of tumor excision equal those of nephrectomy if tumor size does not exceed 4 cm in diameter. Whereas the prognosis of organ-confined tumors is excellent, no curative treatment for primary metastasized RCC is available to date. Immunotherapy - the only systemic treatment modality with clinically relevant response rates - has so far failed to effect a survival advantage for the patient. Surgery is only potentially curative for asychronous metastases occurring more than 2 years after surgery.

Breast cancer: challenges and opportunities

The pace of research in breast cancer has picked up significantly in recent years, due to both increased public awareness and improved technology. The availability of many new agents in an already crowded field has resulted in several challenges (both practical and conceptual) for the research community. This report suggests that the "business-as-usual" approach to drug development has important limitations rendering it inadequate to the current research climate. Future drug development, in the form of biologically targeted therapies, offers the best hope for defeating this disease.

Allergy to bovine beta-lactoglobulin: specificity of immunoglobulin E generated in the Brown Norway rat to tryptic and synthetic peptides

BACKGROUND

Animal models which reflect the induction and development of food-allergic reactions are important in the identification of allergenic potential of food proteins and peptides. A number of rat strains, including PVG, Hooded Lister and Brown Norway have been shown to produce immunoglobulin (Ig) E antibodies to food proteins as well as to inhaled allergens. Previous work in our laboratory using the Brown Norway (BN) rat has shown that specific IgE is produced following administration of ovalbumin and milk products via both enteral and parenteral route; this has allowed us to rank ovalbumin, lactoferrin and bovine serum albumin in terms of their inherent allergenic potential and has enabled us to demonstrate that milk protein allergens recognized by the systemically-sensitized animal are consistent with those recognized by sera from cow's milk-allergic patients (the most common allergens recognized were beta-lactoglobulin and the alpha, beta and kappa-caseins).

OBJECTIVE

To demonstrate that the BN rat model can be used to identify the major IgE-binding peptides from beta-lactoglobulin, a known human food allergen, and that those IgE-binding peptides are similar to those recently identified using sera from cow's milk-allergic patients.

METHODS

BN rats were exposed to beta-lactoglobulin or to semiskimmed milk via the intraperitoneal route in the presence of the adjuvant carrageenan. Specific IgE raised against beta-lactoglobulin was determined by a direct enzyme immunoassay using acetyl-cholinesterase substrate; specific IgG responses were also monitored. Overlapping synthetic peptides and tryptic peptides were used within the ELISA to identify the major and minor IgE-binding immunoreactive sequences.

RESULTS

In terms of comparative immunogenicity, there appeared to be sequences that were predominantly IgE- or IgG-reactive. IgE-dominant regions were amino acid sequences 21-40, 41-60, 107-117 and 148-168 whereas sequences 1-24, 67-77, 82-92, 85-95 and 117-127 appeared more selective for IgG antibody recognition. An increased capacity to induce specific IgE was observed when the allergen was present in the context of whole food.

CONCLUSIONS

These studies provide evidence that the immune system of the BN rat and humans - at least in the case of milk allergens - is recognizing similar protein allergens and indeed, at the molecular level, similar peptide epitopes.

Clinical utility of blood cultures drawn from indwelling central venous catheters in hospitalized patients with cancer

BACKGROUND

Because of concern about low specificity, the American College of Physicians guidelines and expert opinion discourage the use of a central venous catheter when obtaining blood for culture for bacteremia or fungemia. However, data on the reliability of cultures done with blood obtained from a central venous catheter are conflicting.

OBJECTIVE

To determine the sensitivity, specificity, and positive and negative predictive values of cultures done with blood obtained through a central venous catheter compared with peripheral venipuncture.

DESIGN

Retrospective cohort study of hospitalized patients with cancer in whom samples for paired cultures were drawn through a central venous catheter and peripheral venipuncture.

SETTING

Tertiary care, university-affiliated medical center.

PATIENTS

185 patients hospitalized on a hematology-oncology ward between August 1994 and June 1996.

MEASUREMENTS

Blinded assessments of culture results done by infectious disease experts were used as the gold standard. Sensitivity, specificity, and positive and negative predictive values were compared for culture of blood from central catheters and culture of blood from peripheral venipuncture.

RESULTS

Of 551 paired cultures, 469 (85%) were catheter-negative/venipuncture-negative, 32 (6%) were catheter-positive/venipuncture-positive, 17 (3%) were catheter-negative/venipuncture-positive, and 33 (6%) were catheter-positive/venipuncture-negative pairs. For the 82 paired cultures with at least one positive result, blinded determination of true bacteremia or fungemia was made by two infectious disease specialists. For catheter draw compared with peripheral venipuncture, sensitivity was 89% (95% CI, 79% to 98%) and 78% (CI, 65% to 90%) (difference, 11 percentage points [CI, -6 to 28 percentage points]), specificity was 95% (CI, 93% to 97%) and 97% (CI, 96% to 99%) (difference, -2 percentage points [CI, -5 to 0.2 percentage points]), positive predictive value was 63% (CI, 50% to 75%) and 73% (CI, 60% to 86%) (difference, -10 percentage points [CI, -26 to 5 percentage points]), and negative predictive value was 99% [CI, 97% to 100%]) and 98% (CI, 96% to 100%) (difference, 1 percentage point [CI, -0.5 to 3 percentage points]).

CONCLUSIONS

In hospitalized hematology-oncology patients, culture of blood drawn through either the central catheter or peripheral vein shows excellent negative predictive value. Culture of blood drawn through an indwelling central venous catheter has low positive predictive value, apparently less than from a peripheral venipuncture. Therefore, a positive result from a catheter needs clinical interpretation and may require confirmation. However, the use of a catheter to obtain blood for culture may be an acceptable method for ruling out bloodstream infections.

Serum MMP-9 and TIMP-1 levels are related to MRI activity in relapsing multiple sclerosis

OBJECTIVE

To 1) compare monthly serum levels of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of MMP-type 1 (TIMP-1) in patients with relapsing-remitting MS (RRMS) versus healthy controls and 2) determine the relationship among monthly serum levels of MMP-9 and TIMP-1 and MRI activity.

BACKGROUND

Activated T-cells and macrophages secrete MMPs that may facilitate their migration across vascular subendothelial basement membranes into the CNS. The serum concentration of MMP-9 is reported to be higher in patients with RRMS than healthy controls.

METHODS

Monthly evaluations including gadolinium-enhanced (Gd+) brain MRI and measures of serum MMP-9 and TIMP-1 were performed for up to 15 months in 24 patients with RRMS and for up to 4 months in 10 controls.

RESULTS

Serum MMP-9 but not TIMP-1 levels are elevated in RRMS patients compared to healthy controls (p = 0.025, p = 0.61). In a univariate analysis, high MMP-9 and low TIMP-1 levels precede appearance of new Gd+ lesions (respectively; odds ratio = 3.3, p = 0.008; odds ratio = 2.2, p = 0.086). In a multivariate analysis, in comparison to months when MMP-9 is low and TIMP-1 high, MRI scans obtained the month following high MMP-9 and low TIMP-1 serum concentrations are more likely to report new Gd+ lesions (p = 0.0006, odds ratio = 21.5).

CONCLUSION

An increase in the activity of matrix metalloproteinase-9 (MMP-9) relative to tissue inhibitor of MMP-type 1 (TIMP-1) may be related to formation of new MS lesions, suggesting that serum levels of MMP-9 and TIMP-1 may be surrogate markers of disease activity in relapsing-remitting MS.

Identification of multiple Gypsy LTR-retrotransposon lineages in vertebrate genomes

Gypsy LTR-retrotransposons have been identified in the genomes of many organisms, but only a small number of vertebrate examples have been reported to date. Here we show that members of this family are likely to be widespread in many vertebrate classes with the possible exceptions of mammals and birds. Phylogenetic analyses demonstrate that although there are several distinct lineages of vertebrate gypsy LTR-retrotransposons, the majority clusters into one monophyletic clade. Groups of fungal, plant, and insect elements were also observed, suggesting horizontal transfer between phyla may be infrequent. However, in contrast to this, there was little evidence to support sister relationships between elements derived from vertebrate and insect hosts. In fact, the majority of the vertebrate elements appeared to be most closely related to a group of gypsy LTR-retrotransposons present within fungi. This implies either that at least one horizontal transmission between these two phyla has occurred previously or that a gypsy LTR-retrotransposon lineage has been lost from insect taxa.

Randomized trial of peripheral blood progenitor cell vs bone marrow as hematopoietic support for high-dose chemotherapy in patients with non-Hodgkin's lymphoma and Hodgkin's disease: a clinical and molecular analysis

Filgrastim (r-metHuG-CSF)-mobilized peripheral blood progenitor cells (PBPC) and unstimulated bone marrow (BM) were evaluated and compared for reconstitution after high-dose chemotherapy in patients with relapsed Hodgkin's disease (HD) or non-Hodgkin's lymphoma (NHL) with respect to engraftment, overall and relapse-free survival, and contamination by lymphoma cells using molecular analysis of immunoglobulin gene rearrangements. Forty-four patients with either NHL or HD underwent autologous transplantation after high-dose chemotherapy. Patients were randomized to receive either Filgrastim-mobilized PBPC (n = 15) or unstimulated BM (n = 14). An additional 15 patients received PBPC without randomization because of a recent history of marrow involvement by lymphoma. Use of PBPC was associated with faster neutrophil engraftment than BM (11 vs 14 days to an absolute neutrophil count >0.5 x 10(9)/l, P = 0.04), but without any difference in platelet engraftment, infectious complications, or overall or event-free survival. Both BM (65%) and PBPC (73%) were frequently contaminated by tumor cells as assessed by CDR3 analysis. Patients with negative polymerase chain reaction analysis of a BM sample during the study had a trend towards an improved survival; however, BM involvement by disease had no impact on the ability to mobilize or collect PBPC. We conclude that PBPC are as effective as BM in reconstituting hematopoiesis after high-dose chemotherapy and that both products are frequently contaminated by sequences marking the malignant clone.