A survey of pediatric malignancy in West Virginia

The occurrence of malignancy in the pediatric age group is an uncommon but serious event. Since little data are available on the extent, nature or referral patterns of childhood cancer in West Virginia, we conducted a survey of 782 primary care physicians and 17 regional referral centers. The results showed that 249 cases of malignancy in the pediatric age group were reported and that 68% of children with newly diagnosed childhood malignancy were referred to institutions within West Virginia. We conclude that the incidence and distribution of types of malignancy in childhood in West Virginia parallels that of the nation, although there is some regional variation within the state.

Influence of mechanical ventilation on blood lactate in patients with acute respiratory failure

OBJECTIVES

To determine whether mechanical ventilation (MV) may affect blood lactate concentration in patients with acute respiratory failure.

DESIGN

Prospective observational study with follow-up to hospital discharge.

SETTING

A 17-bed medical and coronary intensive care unit in a 650-bed general hospital.

PATIENTS

55 adult patients mechanically ventilated for acute respiratory failure between May 1996 and April 1997 were recruited.

MEASUREMENTS AND RESULTS

Arterial blood samples for determination of plasma lactate and blood gas analysis were taken just before tracheal intubation on spontaneous breathing, and 20 and 60 min after the initiation of controlled MV. Cuff systemic arterial pressure was measured before tracheal intubation and every 10 min during the first h of MV. Hyperlactatemia (arterial blood lactate > or = 2 mmol/l) was present in 21 of the 55 patients studied. After 20 min of MV, there was a decrease in blood lactate from 4.74 +/- 1.78 to 3.07 +/- 1.69 mmol/l (p < 0.01); 40 min later there was a further decrease to 2.63 +/- 1.35 mmol/l (p < 0.05). The decrease in blood lactate was also observed in those patients who after starting MV developed systemic arterial hypotension (p < 0.01). In patients with a normal lactate concentration at the entry to the study, lactate remained the same after 60 min on MV (NS).

CONCLUSIONS

Controlled MV decreases substantially the severity of hyperlactatemia in patients with acute respiratory failure, and any adverse circulatory effects of MV do not alter this beneficial outcome.

3-Alkyl ethers of clocinnamox: delayed long-term mu-antagonists with variable mu efficacy

In recent years there has been considerable interest in the relationship between clocinnamox (C-CAM) and its methyl ether methoclocinnamox (MC-CAM). While C-CAM appears to be an insurmountable mu-antagonist, MC-CAM has been shown to be a potent partial agonist at mu-opioid receptors. To further investigate this relationship we prepared other ethers of C-CAM and evaluated these in opioid receptor binding assays and in vivo in mouse antinociceptive assays and in morphine-dependent monkeys. In opioid binding assays, the ethers were generally mu-selective with affinity equivalent to that of C-CAM itself. Although they displayed little or no efficacy in vitro, some of the ethers showed substantial agonist activity in the in vivo antinociceptive tests. Two of the ethers, the propargyl ether 7 and the cyclopropylmethyl ether 5, were chosen for more detailed analysis in vivo. 7 was shown to have significant mu-agonist character and was able to substitute for morphine in morphine-dependent monkeys. Interestingly, when this agonist effect abated, 7 displayed long-lasting mu-antagonism. In contrast, 5 displayed little agonist activity in vivo and was characterized as a potent, long-acting mu antagonist. Although further work is needed to determine whether metabolism is a crucial factor in determining the pharmacological profile of these ethers, it is clear that 3-O-alkylation is a useful means of varying the mu efficacy displayed by this class of acyl-substituted 14-aminomorphinones. MC-CAM itself has generated considerable interest as a potential pharmacotherapy for opiate abuse. These analogues with differing mu efficacy but retaining the long-lasting mu-antagonist effects provide further opportunities for the development of treatment drugs.

Counting of single protein molecules at interfaces and application of this technique in early-stage diagnosis

The fluorescence-based detection and counting of single protein molecules after specific binding to antibodies at interfaces is presented. A diode laser was used as the excitation source. The unspecific binding at the interface has been reduced to a level of only 0.1% of the maximum signal level. At present, the detection limit of this molecule-counting process is in the range of 10(-17) mol/L, and the dynamic range of the signal corresponds to 7 orders of magnitude of antigen concentration, but these values are not limiting. As a preliminary application in early-stage diagnosis, we have investigated the detection of a single cardiac actin molecule in human plasma, which is of interest in myocardial infarction diagnosis.

Urinary complications of Miami pouch: trend of conservative management

OBJECTIVE

Continent urinary diversions have become popular among gynecologic oncologists. Much information has been gained concerning the complications and current management of patients with continent ileocolonic reservoirs. The high mortality rate associated with reoperation has led clinicians to adopt a trend toward conservative means of management. The purpose of this study was to evaluate the applicability of conservative management of complications related to the creation of the continent ileocolonic reservoir Miami pouch.

STUDY DESIGN

Patients who underwent creation of the Miami pouch at the Division of Gynecologic Oncology, University of Miami School of Medicine, since 1988 have been included in this study. Management of complications, with particular emphasis on the conservative treatment, has been reviewed in detail for each patient. Open surgery and conservative treatment have been compared.

RESULTS

Seventy-seven patients underwent creation of the Miami pouch from February 1988 to September 1997. Sixty (77.9%) patients were affected by recurrent cervical cancer; 72 (93.5%) were previously radiated. The perioperative mortality rate was 11.7% (9 patients). Six of these patients died as a result of sepsis; all of them underwent reoperation at least once. The most common urinary complications were ureteral stricture or obstruction (22.1%), difficult catheterization (19.5%), and pyelonephritis (13%). Conservative management strategies used for these complications included percutaneous nephrostomy, stent placement, balloon dilatation, radiologically (ultrasonography, fluoroscopy, computed tomography) guided placement of catheters, and antibiotic treatment. Eighty percent of the complications associated with the ileocolonic reservoir were resolved with conservative treatment, whereas 16.9% required surgical revision.

CONCLUSION

On the basis of these findings, conservative management of urinary reservoir complications should always be considered before surgical intervention is attempted. The exact time to engage in open revision should be individualized on the basis of the clinical condition of each patient. It is our belief that the conservative approach should be instituted whenever possible but surgical intervention not be delayed when absolutely indicated.

Measurement of how well a paediatric training programme prepares graduates for their chosen career paths

To provide a sound basis for modification of our paediatric residency education programme, we surveyed graduates from the past 16 years. The questionnaire was designed to determine the adequacy of training rotations in preparing graduates for their career paths. Questionnaires were mailed to 81 graduates; 73 (90%) replied. A modified version was completed by 27 of 29 current residents (93%). For most rotations, responses were normally distributed. However, 10 or more respondents identified exposure in one area as 'excessive' and in 6 as 'inadequate'. Current residents scored many rotations as 'inadequate', likely indicative of their limited exposure to actual practice. Recommendations were consistent for subjects needing more instruction. All major issues raised by graduates had been identified by faculty, but the substantiation enabled changes to be made with widespread support. We recommend periodic survey of graduates to evaluate how well education is preparing residents for their ultimate career paths.

Associations of protein C and protein S with serum lipid concentrations

Difficulties in the laboratory measurement of protein C and protein S levels cause problems in the diagnosis of deficiency states in individual patients and may complicate estimation of the prevalence of these states in the general population. Some difficulties may be due to unappreciated influences affecting the measured levels of proteins C and S. We measured protein C activity and antigen, total and free protein S antigen, and serum total cholesterol, high-density cholesterol and triglyceride in a community-based study of 150 adults (73 male, 77 female), age range 23-80 years. Participants were identified from the list of a single general practice by stratified random sampling within sex and decade of age. Protein C activity and antigen were strongly associated with serum lipids, mean levels increasing by approximately 0.25 u/ml as total cholesterol and triglyceride concentration each rose from the 5th to 95th centile. Total protein S antigen concentration was associated with total cholesterol, the mean rising by over 0.1 u/ml as total cholesterol increased from the 5th to the 95th centile, whilst a similar rise in triglyceride was associated with an increase in mean free protein S of more than 0.3 u/ml. Overall, physiological variation in total cholesterol and triglyceride concentration was associated with significant variation in protein C and protein S levels, independent of age and sex, suggesting that it is important to take serum lipids into account when investigating patients for protein C or protein S deficiency. Failure to do so may be misleading in some circumstances.

Retroviral diversity and distribution in vertebrates

We used the PCR to screen for the presence of endogenous retroviruses within the genomes of 18 vertebrate orders across eight classes, concentrating on reptilian, amphibian, and piscine hosts. Thirty novel retroviral sequences were isolated and characterized by sequencing approximately 1 kb of their encoded protease and reverse transcriptase genes. Isolation of novel viruses from so many disparate hosts suggests that retroviruses are likely to be ubiquitous within all but the most basal vertebrate classes and, furthermore, gives a good indication of the overall retroviral diversity within vertebrates. Phylogenetic analysis demonstrated that viruses clustering with (but not necessarily closely related to) the spumaviruses and murine leukemia viruses are widespread and abundant in vertebrate genomes. In contrast, we were unable to identify any viruses from hosts outside of mammals and birds which grouped with the other five currently recognized retroviral genera: the lentiviruses, human T-cell leukemia-related viruses, avian leukemia virus-related retroviruses, type D retroviruses, and mammalian type B retroviruses. There was also some indication that viruses isolated from individual vertebrate classes tended to cluster together in phylogenetic reconstructions. This implies that the horizontal transmission of at least some retroviruses, between some vertebrate classes, occurs relatively infrequently. It is likely that many of the retroviral sequences described here are distinct enough from those of previously characterized viruses to represent novel retroviral genera.

Transrectal ultrasonography: relationship with anorectal manometry, electromyography and sensitivity tests in irritable bowel syndrome

Irritable bowel syndrome is the most frequently diagnosed disorder in gastroenterology. It has been demonstrated with specialized motility studies that these patients compared to healthy subjects show changes in rectoanal electrical and mechanical activity and in rectoanal sensitivity. However, until now no report has been published on morphological alterations in the rectum or the internal anal sphincter. Twenty-five consecutive patients with irritable bowel syndrome (mean age 32, range 17-47 years; 24 females) were evaluated prospectively by transrectal ultrasonography, rectal sensitivity studies, and recordings of both electrical and mechanical activity of the distal rectum and internal anal sphincter during a 2-h inter-digestive period. Ten healthy volunteers (mean age 34.5, range 19-50 years) served as a control group. Paired and non-paired Student's two-tailed t test and linear regression analysis were used. It was shown that muscle thickness of the rectum during rest (4.7 +/- 0.1 mm) was correlated neither with its rectal spike amplitude (0.73 +/- 0.1 mV) nor with rectal spike frequency (17.06 +/- 3.6 spike/2 h). In addition, the diameter of the internal anal sphincter (1.2 +/- 0.1 mm) was correlated neither with its resting pressure, nor with frequency (17.1 +/- 3.2/2 h), duration (14.9 +/- 1.5 s), or amplitude (14.1 +/- 1.9 mmHg), of inhibition of the spontaneous rectoanal inhibitory reflex. No correlation was found between ultrasonographic parameters and rectal distension variables (r = 0.03). This study demonstrates for the first time morphological anorectal changes in patients with irritable bowel syndrome compared to healthy subjects, in addition to showing that morphological changes are independent of physiological ones. Therefore both transrectal ultrasonography to determine anorectal morphology and electromanometry to assess anorectal function are important measures in the evaluation of patients with irritable bowel syndrome.

Large-scale taxonomic profiling of eukaryotic model organisms: a comparison of orthologous proteins encoded by the human, fly, nematode, and yeast genomes

Comparisons of DNA and protein sequences between humans and model organisms, including the yeast Saccharomyces cerevisiae, the nematode Caenorhabditis elegans, and the fruit fly Drosophila melanogaster, are a significant source of information about the function of human genes and proteins in both normal and disease states. Important questions regarding cross-species sequence comparison remain unanswered, including (1) the fraction of the metabolic, signaling, and regulatory pathways that is shared by humans and the various model organisms; and (2) the validity of functional inferences based on sequence homology. We addressed these questions by analyzing the available fractions of human, fly, nematode, and yeast genomes for orthologous protein-coding genes, applying strict criteria to distinguish between candidate orthologous and paralogous proteins. Forty-two quartets of proteins could be identified as candidate orthologs. Twenty-four Drosophila protein sequences were more similar to their human orthologs than the corresponding nematode proteins. Analysis of sequence substitutions and evolutionary distances in this data set revealed that most C. elegans genes are evolving more rapidly than Drosophila genes, suggesting that unequal evolutionary rates may contribute to the differences in similarity to human protein sequences. The available fraction of Drosophila proteins appears to lack representatives of many protein families and domains, reflecting the relative paucity of genomic data from this species.

Transmyocardial laser-revascularization: experimental studies on prolonged acute regional ischemia

OBJECTIVE

This experimental study in pigs was undertaken to answer the question whether TMLR after acute myocardial infarction may improve regional myocardial perfusion, left ventricular function and diminish myocardial necrosis in the area at risk.

METHODS

Thirty open-chest anesthetized pigs were observed for 6 h, six pigs served as controls. In 24 pigs, occlusion of the left anterior descending artery (LAD) beyond the first diagonal branch was performed: seven pigs had LAD occlusion only (ischemia group), and 17 pigs were treated by TMLR (using a CO2-laser, energy: 40 J) prior to coronary occlusion; nine pigs received one laser channel (1 mm diameter) per cm2 (laser group 1) and eight pigs two channels per cm2 in the LAD territory (laser group 2). Regional myocardial blood flow by microspheres, function (franc starling curves), histochemical assessment (triphenyl tetrazolium chloride, TTC and histology), were performed.

RESULTS

The lased pigs were less prone to ventricular fibrillation (laser group 2, 38%; laser group 1, 56%; ischemic group, 100%; P < 0.05), and showed a significant smaller area of necrosis (TTC) in the area at risk (laser group 1, 23%; laser group 2, 14%; vs. ischemia group, 31%; P < 0.01). There was no significant difference between laser-treated and ischemia hearts regarding the amount of blood flow into the infarcted LAD region and the maximal left ventricular stroke work index after 6 h (P = n.s). Regional myocardial blood flow: ischemia group, 4 +/- 5 ml/100 g/min; laser group 1, 3 +/- 10 ml/100 g/min, and laser group 2, 2 +/- 10 ml/100 g/min; maximal left ventricular stroke work index: ischemia group, 1.8 mJ/g; laser group 1, 2.1 mJ/g and laser group 2, 2.1 mJ/g.

CONCLUSIONS

This model of acute regional ischemia demonstrates that CO2-laser revascularization diminish significantly the incidence of ventricular fibrillation and necrosis in the area at risk, and does not change regional myocardial perfusion and global left ventricular function. This experiment indicates that TMLR may be an alternative in treating advanced ischemic heart disease.

Travel health: non-vaccine preventable risks

This article discusses non-vaccine preventable health hazards associated with foreign travel. It outlines the main risks involved and describes the kind of advice on prevention and treatment that nurses can offer to people travelling abroad on holiday or business.

Direct channel-gating and modulatory effects of triiodothyronine on recombinant GABA(A) receptors

We have previously shown that triiodothyronine (T3) inhibits gamma-aminobutyric acid type A (GABA(A)) receptors in synaptoneurosomes and transfected cells. To further characterize this phenomenon, the effect of T3 on recombinant GABA(A) receptors expressed in Xenopus oocytes was investigated using the two-electrode voltage-clamp method. T3 inhibited GABA-gated chloride currents in a non-competitive manner and yielded an IC50 of 7.3 +/- 0.8 microM in oocytes coexpressing alpha1beta2gamma2L receptor subunits. T3 had no inhibitory effect on alpha6beta2gamma2L or beta2gamma2L receptor constructs, indicating that the alpha1 subunit imparts T3 sensitivity to the receptor. In addition to the inhibitory effect of T3 on GABA responses, T3 alone induced a current in oocytes expressing alpha1beta2gamma2L, alpha6beta2gamma2L and beta2gamma2L constructs. This current displayed a reversal potential identical to that of GABA-gated chloride currents, and was blocked by picrotoxin (10 microM), but not by bicuculline (50 microM), indicating that T3 gates the chloride channel by binding to a site other than the GABA-binding site. The direct channel-gating action of T3 was concentration-dependent, with an EC50 of 23 +/- 5 microM. The actions of T3 are unique in that T3 acts as a noncompetitive antagonist in the presence of GABA but can directly gate the chloride channel in the absence of GABA.

Physical assault in New Zealand: the experience of 21 year old men and women in a community sample

AIM

To obtain epidemiological information on physical assault in a high risk group of New Zealanders.

METHOD

Rates of physical assault in the preceding twelve months were ascertained by interview in a cohort of 21 year old, Dunedin-born men (n = 482) and women (n = 462).

RESULTS

Forty-five percent of the men and one quarter of the women reported at least one physical assault, either completed, attempted or threatened. A small proportion of these received medical treatment. Most serious assaults were by a perpetrator who was thought to have been drinking alcohol. Most assaults on men were by strangers but partners carried out more assaults against women, especially those receiving medical treatment. One quarter of all assaults on women were by other women, compared to 15% of the assaults on men. Differences between patterns of assaults on women and on men are discussed.

CONCLUSION

It is important for doctors to be aware of the widespread occurrence of interpersonal violence in New Zealand and its underreporting.

Does withholding gonadotrophin administration prevent severe ovarian hyperstimulation syndrome?

Withholding gonadotrophin administration (coasting) may prevent severe ovarian hyperstimulation syndrome (OHSS). To ascertain the effectiveness of this protection a cohort of 252 consecutive in-vitro fertilization (IVF) or IVF with intracytoplasmic sperm injection (ICSI) cycles was studied. Twenty women with exaggerated response were treated with coasting. Despite coasting, four patients developed severe OHSS requiring hospitalization. Two of these four patients also required paracentesis. Multiple regression analysis in coasting cycles revealed severe OHSS was related to youth, number of oocytes retrieved and serum oestradiol prior to human chorionic gonadotrophin (HCG). Risk of developing severe OHSS was multifactorial and not necessarily prevented by withholding gonadotrophin.

Histologic findings of transmyocardial laser channels after two hours

Histologic examination of the human myocardium has been performed several days, weeks, and months after transmyocardial laser revascularization. We performed microscopic examinations 2 hours postoperatively. In addition to the patent channel (diameter, 1 mm) and a 1-to 2-mm rim of necrosis, a 1- to 3-mm zone of myofibrillary degeneration was found. This additional reversible injury immediately after transmyocardial laser revascularization could explain the higher mortality rate in patients with reduced left ventricular function.

Morphology of basal optic tract terminals in the turtle, Pseudemys scripta elegans

The morphologies of axon terminals of retinal ganglion cells projecting to the basal optic nucleus (BON) via the basal optic tract (BOT) were studied in the red-eared turtle. The BOT was visualized on the ventral surface of the brainstem in vitro, and either biotinylated dextran amine was injected extracellularly or neurobiotin was injected into physiologically identified axons during intracellular recordings. Up to 16 hours after tracer injection, the brains were fixed, sectioned parasagittally, and stained for biotin and Nissl substance. The diameters and depths of extracellularly filled axons were measured at three BON sites. Fourteen axons were reconstructed from serial sections with the aid of appropriate computer software. Analysis of extracellularly filled retinal axons revealed that about three times more axons were present just inside the rostral border of the BON compared with its caudal border. Thick (2-4 microm) axons were located within 100 microm from the ventral border, whereas thin (<2 microm) axons were found throughout the nucleus. Only the thinnest axons (<1 microm) extended caudally from the nucleus, indicating that some extracellularly labelled fibers passed through the BON. The intracellularly filled axons were more similar to the thick axons filled extracellularly and arborized entirely within the BON. All of the intracellularly filled axons had thick ventral trunks from which many thin branches extended dorsally and obliquely within the BON. The thin branches bifurcated repeatedly to form bead-like varicosities or boutons that often formed clusters within regions of 150 microm3 or less. These clusters may reflect areas of focused synaptic contact on BON cells with specific direction preferences.

The use of alternative therapies by children with asthma: a brief report

OBJECTIVE

To identify the nature and prevalence of alternative therapies used by children with asthma attending a children's hospital.

METHODOLOGY

Subjects consisted of a consecutive series of 51 children with asthma aged 1-6 years who were attending the Women's and Children's Hospital, South Australia. Parents of the children completed a questionnaire describing the use of alternative therapies by the children.

RESULTS

Approximately 55% of children used alternative therapies for asthma management. Therapies used most commonly were massage, relaxation exercises, diet therapy and vitamins. There was no significant difference in the age, asthma severity, length of time since diagnosis or presence of another illness amongst children who did or did not use alternative therapies.

CONCLUSIONS

A substantial proportion of children with asthma who attend paediatric clinics use alternative therapies. Paediatricians should be aware of this and be prepared to discuss alternative therapies with parents. This may facilitate more open doctor-patient relationships and better management of children's asthma.

Protein folding assisted by the GroEL/GroES chaperonin system

The chaperonin system GroEL/GroES assists in the folding of proteins in the bacterial cytosol. Recent applications of biophysical techniques for the structural analysis of GroEL, GroES, and chaperonin-bound protein folding intermediates have provided the basis for understanding the molecular mechanism of GroEL/GroES action. GroEL, a double-ring complex, binds unfolded proteins at its inner ring surface. Protein folding proceeds in the central cavity of GroEL, after dissociation of the polypeptide has been triggered by ATP hydrolysis in GroEL. Premature release of unfolded protein into external solution is prevented by binding of the cofactor GroES on top of the GroEL cylinder, resulting in an enclosed cage. Upon ATP-dependent dissociation of GroES, substrate protein is eventually released from GroEL in a native or native-like conformation. While current in vitro results about the structure, function, and molecular mechanism of GroEL/GroES-assisted protein folding have led to a quite detailed picture of this complex process, the extent to which the GroEL/GroES system actually participates in the folding of newly-synthesized proteins in the cell is less defined and remains a subject for further studies. Ingenious biochemical and genetic approaches will be necessary to show whether our current view of chaperonin action indeed accurately reflects its modus operandi inside a living cell.