A versatile method is described for preparing aryl nitrogen mustard-oligodeoxyribonucleotide (mustard-ODN) conjugates under anhydrous conditions. The chemistry uses DMSO soluble triethylammonium or tributylammonium salts of the ODNs. A G/A motif triplex forming ODN was chosen for study since it had been shown earlier to bind with high affinity and specificity to a duplex DNA target. A 5'-hexylamine derivative of this ODN was reacted with three different 2,3,5,6-tetrafluorophenyl ester derivatives of aryl nitrogen mustards which were designed to have different alkylation rates. An HPLC assay was used to determine reaction rates of these mustard-ODNs under various conditions. The reactivity of the mustard groups depended on chloride concentration and the presence of nucleophiles. Conjugation of mustards to G/A-containing ODNs decreased their aqueous stability. Hydrolysis and alkylation rates of these agents were consistent with reaction via an aziridinium intermediate. Rates of sequence specific alkylation within a triplex were determined by denaturing gel electrophoresis and shown to depend on inherent reactivity of the mustard group. The improved synthesis and chemical characterization of mustard-ODNs should facilitate their use as sequence specific alkylating agents and as probes for nucleic acid structure.

Alkylation↗

PubMedDate not supplied

Fire hazard in the operating room.

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Fires↗

PubMedDate not supplied

Automatic noninvasive blood pressure monitors: analog/manual adaptation of Dinamap (TM).

This paper describes some of the features and limitations of the newly-developed, automatic, noninvasive blood pressure monitors. In particular, an analog/manual modification is presented which can be adapted to a variety of such devices. The manual/automatic adaptation of the Critikon Dinamap (TM) blood pressure monitor is specifically described. This modification provides continuous observation of cuff pressure and permits the option of manual cuff inflation and deflation. The analog/manual adaptation is useful in special patient conditions and as a teaching aid.

Blood Pressure Determination↗

PubMedDate not supplied

Preparing anesthesia equipment for suspected malignant hyperthermia episodes.

Malignant hyperthermia is a relatively rare condition which strikes susceptible patients undergoing surgery. This disorder is an inherited biochemical defect, triggered by certain anesthetic agents and stress. The patient suffers a rapid and potentially dangerous rise in temperature, brought about by an increase in metabolism. If a patient, by family history or test, is suspected of being susceptible to malignant hyperthermia, special precautions must be taken before proceeding with surgery. The clinical engineer must: 1) prepare special anesthesia equipment which is free of trace gases capable of triggering an episode of malignant hyperthermia; 2) provide special monitoring facilities to detect the onset of an episode; and 3) have treatment facilities on hand in the event that an episode does develop.

Anesthesiology↗

PubMedDate not supplied

A standards primer.

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Biomedical Engineering↗

PubMedDate not supplied

A neonatal insert adaptor for a capnometer breathe-through cell.

This paper describes a neonatal insert for use with the Hewlett-Packard Model 47210A capnometer airway adaptor. Dead space using this adaptor is 4.2 ml, which compares to 28.4 ml with the standard adaptor system and 4.0 ml with the pediatric Y-piece and endotracheal tube alone. Resistance was evaluated by plotting pressure drop-flow relationships. For oxygen flow rates used of up to seven L/min, the neonatal insert reduced the pressure drop as compared to both the standard adaptor and the pediatric Y-piece and endotracheal tube alone. Pressure drops were not very much larger than calculated theoretical values.

Carbon Dioxide↗

PubMedDate not supplied

Effective communication and supervision in the biomedical engineering department.

It is important for biomedical engineering supervisors to master the art of effective communication. Supervisors who have effective communication skills can successfully initiate creative programs and generate a harmonious working atmosphere. Using effective communication, they can promote good working conditions, such as high morale, worker initiative and loyalty to the department, which are almost impossible to measure but imperative for a successful department. However, effective communication tends to be neglected by supervisors who are either functional specialists or managerial generalists. This paper presents several cases of what effective communication truly is and discusses some potential factors that may lead to ineffective communication.

Biomedical Engineering↗

PubMedDate not supplied

Anorectal function and continence mechanisms in childhood encopresis.

We compared anorectal sensory and motor functions, expulsion dynamics, and continence mechanisms in 50 children with encopresis and 21 healthy control children. When expulsion dynamics were studied, 43% of boys with encopresis inappropriately contracted the muscles near the anal canal compared with 10% of girls with encopresis (p greater than 0.05) and 10% of control children of both sexes (p less than 0.05). In contrast to previous studies we demonstrated no abnormalities of thresholds of conscious rectal sensation or internal anal sphincter relaxation. In addition, children with encopresis had no demonstrable abnormalities of rectosphincteric continence mechanisms or strength of external anal sphincter contraction. We conclude that a significant number of boys with encopresis have abnormal anorectal expulsion dynamics, which may contribute to chronic fecal retention and incontinence. Abnormalities of anorectal sensory and motor function and of rectosphincteric continence mechanisms do not seem to be important in the pathogenesis of childhood encopresis.

Adolescent↗

PubMedDate not supplied

Evaluation of biofeedback in childhood encopresis.

In order to evaluate the efficacy of biofeedback for childhood encopresis, 50 children with encopresis were prospectively studied and randomized to receive biofeedback (B) or mineral oil therapy (M). Specificity of biofeedback was also evaluated by comparing outcomes of both regimens in children with normal (n = 32) and abnormal (n = 18) defecation patterns. Using a single blinded design, there were no significant differences in clinical outcomes between the 24 children receiving B and the 26 children receiving M at 3, 6, and 12 months. However, at 12 months six of nine children with abnormal defecation patterns were in remission or markedly improved after receiving B, compared to only three of nine children receiving M. In contrast, children with normal patterns appeared to respond better to M than did those receiving B (71 vs. 40% at 12 months). Biofeedback appears to warrant further evaluation in children with encopresis and abnormal defecation patterns.

Adolescent↗

PubMedDate not supplied

The effect of laboratory stressors on glycemic control and gastrointestinal transit time.

This study compared effects of an active coping task (computerized stressors involving arithmetic, anagrams, and Atari games) and a passive coping task (cold pressor) on gastrointestinal transit time and glycemic response to an oral glucose load. Eleven normal weight males were studied; subjects participated in three counterbalanced sessions, each including a 45-minute baseline, 20-minute experimental period (active coping, passive coping, or nonstress control) and 2.5-hour recovery period. The stressors produced different cardiovascular and catecholamine responses; systolic and diastolic blood pressure were highest during cold pressor (p less than 0.001), heart rate was highest during computer stressor (p less than 0.001), and norepinephrine excretion was greatest during cold pressor (p less than 0.002). However, both stressors delayed gastrointestinal transit time compared with the control condition (p less than 0.009 and p less than 0.026 for cold pressor and computerized stressor, respectively) and both delayed the time of peak glucose response (p less than 0.002 and p less than 0.05, respectively). Implications of these findings for patients with diabetes and for effects of stress on eating behavior are discussed.

Adaptation, Psychological↗

PubMedDate not supplied

Horatio B. Williams and the first electrocardiographs made in the United States.

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Electrocardiography↗

PubMedDate not supplied

Chronic headache in the shunt-dependent adolescent with nearly normal ventricular volume: diagnosis and treatment.

The shunt-dependent adolescent will occasionally manifest shunt malfunction by intermittent or chronic headache without any obvious signs of increased intracranial pressure (ICP). A small percentage of these patients will have nearly normal ventricular volume, making the diagnosis and treatment difficult. The authors present a comprehensive approach to this problem that uses computerized axial tomography (CT), ICP monitoring, positive contrast or isotope shunt scan, shunt revision, subtemporal craniectomy, or medical management as the individual situation dictates. The CT scan identifies patients with nearly normal ventricular volume. ICP monitoring then determines whether there is shunt malfunction. The shunt scan aids in localization of the malfunction. For distal obstruction, a simple revision is performed. When proximal shunt malfunction occurs, either subtemporal craniectomy or revision is carried out. It has been documented that occasionally ICP is episodically increased in the absence of shunt malfunction. This is secondary to abnormal brain compliance, and subtemporal craniectomy alone or in conjunction with corticosteroids is curative. This comprehensive approach is designed to provide a method for recognizing and treating intermittently increased ICP in the shunt-dependent child.

Adolescent↗

PubMedDate not supplied

Constipation in elderly patients. Pathogenesis and management.

The incidence of constipation appears to increase with increasing age, particularly after the age of 65. There are few data on the age-related physiological changes of colonic and anorectal function; however, anal sphincter pressures are decreased in elderly patients, while colonic transit time does not appear to be altered. The successful management of constipation in elderly patients requires an understanding of colorectal function, careful characterisation of the patient's complaint, and in selected patients, specialised studies of colonic and anorectal function. The cause of constipation in elderly patients is often multifactorial and may include inactivity, inappropriate diet, depression and confusion, certain medications, and neuromuscular disorders. The treatment of chronic constipation should be based on the nature of the complaint and the presumed pathophysiological mechanisms at work in each patient. Treatment will be based on one or more strategies including dietary changes, laxatives, and in carefully defined cases, surgery.

Aged↗