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Biomedical subjects

J B White

Publications and source records attributed to J B White.

At least 19 recordsLinked to original sources
PubMed1992

Two gap junction genes, connexin 31.1 and 30.3, are closely linked on mouse chromosome 4 and preferentially expressed in skin.

Two new gap junction genes isolated from the mouse genome code for connexin homologues of 271 and 266 amino acids, designated here Cx31.1 and Cx30.3, respectively. The two open reading frames, oriented in the same direction, are only 3.4 kb apart on mouse chromosome 4. Within the connexin family, these two proteins are most closely related to one another (70% amino acid sequence identity) and to Cx31 (65 and 68% identity, respectively). Comparison of the Cx31.1 mouse gene with a Cx31.1 cDNA showed a similar genomic organization to that found with other members of the connexin gene family, i.e. the coding and 3'-untranslated regions are contained within a single exon, which is preceded by an intron, less than 25 bases upstream of the ATG start codon. Northern blot hybridization revealed highly tissue-specific coexpression of the 1.6-kb Cx31.1 mRNA and two Cx30.3 transcripts of 1.9- and 3.2-kb size, predominantly in skin and two related mouse keratinocyte cell lines. Minor levels of Cx31.1 mRNA were detected in testis. Microinjection of Cx30.3, but not Cx31.1 cRNA, into Xenopus oocyte pairs induced formation of functional gap junction channels with unique voltage-gated parameters compared to other connexins expressed similarly.

Amino Acid Sequence↗
PubMed1990

Evaluating sources of indoor air pollution.

Evaluation of indoor air pollution problems requires an understanding of the relationship between sources, air movement, and outdoor air exchange. Research is underway to investigate these relationships. A three-phase program is being implemented: 1) Environmental chambers are used to provide source emission factors for specific indoor pollutants; 2) An IAQ (Indoor Air Quality) model has been developed to calculate indoor pollutant concentrations based on chamber emissions data and the air exchange and air movement within the indoor environment; and 3) An IAQ test house is used to conduct experiments to evaluate the model results. Examples are provided to show how this coordinated approach can be used to evaluate specific sources of indoor air pollution. Two sources are examined: 1) para-dichlorobenzene emissions from solid moth repellant; and 2) particle emissions from unvented kerosene heaters. The evaluation process for both sources followed the three-phase approach discussed above. Para-dichlorobenzene emission factors were determined by small chamber testing at EPA's Air and Energy Engineering Research Laboratory. Particle emission factors for the kerosene heaters were developed in large chambers at the J. B. Pierce Foundation Laboratory. Both sources were subsequently evaluated in EPA's IAQ test house. The IAQ model predictions showed good agreement with the test house measurements when appropriate values were provided for source emissions, outside air exchange, in-house air movement, and deposition on "sink" surfaces.

Air Pollution↗
PubMed1989

Interrelations among children, parents, premedication, and anaesthetists in paediatric day stay surgery.

OBJECTIVE: To investigate the incidence of difficulties associated with parental presence during the induction of anaesthesia in children and the influence of premedication with special reference to vomiting after papaveretum. DESIGN: Mixed factual and multiple choice questionnaire completed by medical and nursing staff and parents during and after admission. SETTING: Teaching hospital with regional paediatric general surgical unit where parental presence during induction of anaesthesia is long established. PATIENTS: 151 Children aged 1-14 years who had not previously undergone surgery attending with parents for day stay general surgical procedures. INTERVENTION: Children were randomly allocated to receive no premedication (group 1), oral diazepam elixir (0.3 mg/kg) (group 2), or intramuscular papaveretum with hyoscine (0.3 mg/kg with 0.006 mg/kg) (group 3). No other modification to established day stay routine was made. RESULTS: No major problems were associated with the presence of parents during the induction of anaesthesia. Only 10 of the 141 parents who accompanied their child caused some difficulty, and five became distressed. Premedication with both diazepam and papaveretum resulted in sedation but did not ease induction of anaesthesia. Papaveretum greatly reduced pain and distress immediately after the operation, pain and discomfort being observed in only 15% of children (7/48) compared with 66% (27/41) in group 1 and 49% (22/45) in group 2. Papaveretum, however, must be given intramuscularly, and nurses observed that the children preferred being given premedication orally to intramuscularly. In addition, the incidences of nausea and vomiting were significantly higher in the postoperative ward and at home with papaveretum, although no patient who had been given the drug was nauseous or vomited in the recovery area. The incidences of nausea in group 3 were 62% (31/50) and 57% (27/47) in the postoperative ward and at home, respectively, v 21% (7/33) and 14% (4/29) in group 1 and 13% (5/38) and 14% (5/37) in group 2; the incidences of vomiting in group 3 were 60% and 43% in the postoperative ward and at home, respectively, v 18% and 7% in group 1 and 11% and 11% in group 2. Finally, neither the administration or otherwise of premedication nor the drug given affected the children's or parents' perception of day care surgery. CONCLUSIONS: Difficulties with parents in anaesthetic rooms were not common or severe. Premedication provides preoperative sedation and papaveretum improves the immediate postoperative course but the incidences of nausea and vomiting after operation are higher with its use than without.

Ambulatory Surgical Procedures↗
PubMed1989

Analgesia following inguinal herniotomy or orchidopexy in children: a comparison of caudal and regional blockade.

The effectiveness of postoperative analgesia was compared in 44 children undergoing inguinal surgery, 19 of whom received caudal analgesia (1 ml 0.2% bupivacaine/kg) and 25 ilioinguinal block (0.25 ml 0.5% bupivacaine/kg). The requirement for supplementary analgesia (intramuscular morphine) was less in the caudal group, although this did not reach statistical significance in the number studied. Ilioinguinal and caudal blockade both provide useful postoperative analgesia for children following ilioinguinal surgery.

Analgesia↗
PubMed1988

Plasma bupivacaine concentrations during caudal analgesia and ilioinguinal-iliohypogastric nerve block in children.

Plasma bupivacaine concentrations were measured in 27 children aged 3-7 years who received one of two analgesic regimens for herniotomy or orchidopexy. Analgesia was provided either by caudal epidural bupivacaine 0.2% 2 mg/kg (n = 14) or by ilioinguinal-iliohypogastric nerve block with bupivacaine 0.5% 1.25 mg/kg (n = 13). Mean (SD) peak venous bupivacaine concentrations were 0.57 (0.17) microgram/ml and 0.79 (0.38) microgram/ml respectively. Time to peak plasma concentrations were 29.6 (7.9) and 22.3 (10.9) minutes respectively. These concentrations are well below the potentially toxic level of 4.0 micrograms/ml, but suggest that uptake of bupivacaine is more rapid after ilioinguinal-iliohypogastric nerve block than during caudal analgesia.

Anesthesia, Caudal↗
PubMed1988

Cardiac tamponade: a review of diagnosis and anaesthetic and surgical management illustrated by three case reports.

Cardiac tamponade is an uncommon problem in a district general hospital. Three patients were admitted to the intensive therapy unit at Northampton General Hospital with tamponade in a 7-week period, each with a different underlying aetiology. Their case histories are presented and the management in the light of these described. The aetiology, physiology, clinical signs and investigations leading to the diagnosis are considered. In the discussion the opportunity is taken to review the recent literature on the subject.

Adult↗
PubMed1987

Anaesthesia for paediatric tonsillectomy. Comparison of spontaneous ventilation and intermittent positive pressure ventilation.

Fifty children undergoing tonsillectomy were anaesthetized using either a spontaneous ventilation (SV) technique with halothane (and nitrous oxide in oxygen) or intermittent positive pressure ventilation (IPPV) (with nitrous oxide, in oxygen) facilitated by atracurium 0.5 mg kg-1. Time to full recovery was significantly less in the IPPV group (1.8 +/- 3.79 min) than the SV group (20.0 +/- 6.77 min) (P less than 0.001) and ventilated children had a better quality of long-term recovery (sleep score 1.02 for the SV and 1.44 for the IPPV groups) (P less than 0.01). Apart from a significantly greater E'CO2 in the halothane group (7.3 kPa +/- 0.9 compared with 5.1 kPa +/- 0.5) (P less than 0.001), there was no significant difference in operative or postoperative morbidity.

Anesthesia Recovery Period↗
PubMed1986

Cardiovascular and renal effects of buspirone in several animal models.

Intravenous administration (0.3 or 3 mg/kg) of buspirone to anesthetized rats elicited a transient pressor response (14 +/- 2 mmHg) and sustained bradycardia. However, oral administration (30 mg/kg) reduced the blood pressure and heart rate of conscious normotensive (-14 +/- 4 mmHg) and DOCA-salt hypertensive rats (-22 +/- 5 mmHg). Buspirone (3-100 mg/kg, p.o.) elicited increases in urinary volume and electrolyte excretion of conscious normotensive rats and decreased these parameters in conscious mice. Buspirone was observed to possess alpha 1-adrenoceptor agonist activity in ganglion-blocked anesthetized rats. Buspirone (0.3-3 mg/kg, i.v.) elicited transient elevations in the blood pressure of open-chest anesthetized dogs. There was a sustained increase in total peripheral resistance and a decrease in aortic blood flow, heart rate, right ventricular contractile force and left ventricular dp/dt max. Intravenous and oral administration to anesthetized and conscious dogs elevated urinary volume and electrolyte excretion. However, the doses used to elicit the observed alterations in hemodynamic/renal function are considerably greater than those which produce anxiolytic effects. Thus, it is doubtful that anxiolytic doses of buspirone will produce cardiovascular alterations in patients.

Anesthesia↗
PubMed1985

Practice of preoperative assessment by anaesthetists.

The practice of preoperative assessment in 24 departments of anaesthesia in Great Britain and Ireland was surveyed. Most departments had no rigid policies governing assessment, and many served several hospitals. There was little evidence that admission procedures of patients scheduled for surgery or the organisation of operating lists took account of the problems encountered by anaesthetists undertaking preoperative assessment. From the participating departments 415 anaesthetists completed a questionnaire of their individual practice. Most (57%) visited at least 80% of their patients preoperatively, but 22% saw less than 50% of patients. The detection of potential anaesthetic problems and the establishment of rapport with patients were highly rated reasons for conducting such visits. Failure to visit was often related to organisational defects within the hospital service, and anaesthetists saw little prospect of improving these defects. The demands created by the needs of preoperative assessment on the one hand, and the need for a rapid turnover of surgical patients and financial stringency on the other, conflict, and this conflict is not easily reconciled.

Anesthesia Department, Hospital↗
PubMed1982

Acute and chronic diuretic-induced alterations in urinary sodium and calcium excretion in the conscious rat.

The acute and chronic (5-day) effects of three low-ceiling diuretics (hydrochlorothiazide, indapamide or xipamide) and two high-ceiling diuretics (furosemide or muzolimine) on urinary volume and electrolyte excretion were examined in the saline-loaded conscious rat. The three low-ceiling agents produced qualitatively similar alterations in both acute and chronic volume and electrolyte excretion patterns. Each of these agents produced an acute disassociation between urinary sodium and calcium excretion and hypocalciuria after chronic administration. It is suggested that indapamide and xipamide, like hydrochlorothiazide, inhibit sodium but not calcium reabsorption in the distal nephron. Acute as well as chronic treatment with either furosemide or muzolimine produced dose-dependent increases in urinary volume and electrolyte excretion. A generally parallel response was observed on sodium and calcium excretion with these agents. It is suggested that muzolimine, like furosemide, inhibits both sodium and calcium reabsorption in the ascending limb of Henle's loop.

Animals↗