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Biomedical subjects

P H Martin

Publications and source records attributed to P H Martin.

12 recordsLinked to original sources
PubMed2001

Two novel alternatively spliced 9-bp exons in the COL4A5 gene.

The existence of an alternatively used 18-bp sequence has been described in type IV collagen alpha 5 chain mRNA from human kidney (Guo et al., Kidney Int 44, 1993). In this study we have shown that this sequence is encoded by two exons, termed 41A and 41B, that are located in a 9-kb intron 41 that was sequenced in its entirety. The sequences of exon 41A and 41B were shown to be present in mRNAs from a variety of tissues.

Alternative Splicing↗
PubMed1999

Cellular source in ewes of prostaglandin-endoperoxide synthase-2 in uterine arteries following stimulation with lipopolysaccharide.

Prostaglandin-endoperoxide synthase (PTGS) (also known as cyclooxygenase) converts arachidonic acid into several prostaglandins, many of which have roles in vasodilation and vasoconstriction under normal and pathological conditions. There are two isoforms of PTGS: PTGS-1 and PTGS-2; PTGS-1 is constitutively expressed in many tissues and is believed to be involved in the homeostatic maintenance of the body. In contrast, PTGS-2 is believed to have a "differentiative" role in the cells and is highly inducible during inflammation and in response to lipopolysaccharide (LPS). Endothelial cells as well as vascular smooth muscle cells can be a source of PTGS within the artery. The objective of this study was to determine the cell population(s) in uterine arteries that respond to LPS with an increase in PTGS-2 protein expression. Uterine arteries collected from ewes during the follicular (Day 0, Day 0 = estrus, n = 4) or luteal (Day 10, n = 4) phase were treated in vitro with LPS as intact artery segments, cut-open artery segments, or cut-open and denuded (endothelial cells absent) artery segments. After 24 h of LPS treatment, intact, cut-open, and denuded uterine artery segments were collected into homogenization buffer for determination of PTGS-2 protein levels by Western blot analysis. The culture medium was collected and used for detection of 6-keto-prostaglandin F(1alpha) (6-keto-PGF(1alpha)), the stable metabolite of prostacyclin, using an enzyme immunoassay. In addition, the location of PTGS-2 after LPS treatment was analyzed by immunohistochemistry in intact artery segments. Denuded arteries (endothelium absent) did not show increases in PTGS-2 protein in the homogenates or 6-keto-PGF(1alpha) in the culture medium after LPS exposure. In contrast, cut uterine arteries responded to LPS stimulation with a significant increase in PTGS-2 protein in homogenates and 6-keto-PGF(1alpha) in culture medium. Immunohistochemical staining for PTGS-2 was associated with both endothelial cells and vascular smooth muscle cells. These results suggest that while both endothelial cells and vascular smooth muscle cells are associated with PTGS-2, after LPS exposure it is the endothelial cells that are essential in uterine artery increases in PTGS-2 and prostacyclin in response to LPS stimulation.

6-Ketoprostaglandin F1 alpha↗
PubMed1998

A comparison of the effects of intravenous tramadol, codeine, and morphine on gastric emptying in human volunteers.

UNLABELLED: We compared the effects of i.v. tramadol (1.25 mg/kg), codeine (1 mg/kg), morphine (0.125 mg/kg), and saline on gastric emptying in 10 healthy human volunteers using a double-blind, randomized, cross-over design. Subjects received one treatment at each of four sessions, 2 wk apart. Gastric emptying was studied using the paracetamol absorption test. There were significant differences when comparing all treatments for concentration-time data (P = 0.002), peak serum paracetamol concentrations (Cmax; P < 0.001), times at Cmax (Tmax; P = 0.003), and areas under the curves from Time 0 to 360 min (AUC(0-360); P = 0.049). Morphine profoundly inhibited gastric emptying. Tramadol had measurable but statistically insignificant inhibitory effects on gastric emptying compared with saline (mean +/- SEM: Cmax 22.4 +/- 2.2 vs 26.8 +/- 2.5 mg/L [P = 0.19], Tmax 33 +/- 5.4 vs 19.5 +/- 2.3 min [P = 0.054] for tramadol versus saline, respectively). Compared with morphine, the Cmax (P < 0.01), Tmax, and AUC(0-360) (P < 0.05) values for tramadol were significantly different. The Tmax value for codeine (63.3 +/- 11.7) was greater than that for tramadol (P = 0.034). We conclude that tramadol has a measurable but smaller inhibitory effect on gastric emptying compared with other opioids. IMPLICATIONS: We compared the effect of tramadol, an unconventional opioid painkiller, on stomach emptying with that of codeine and morphine in a human volunteer study. Tramadol had a measurable but smaller effect and may have clinical and economic advantages in acute pain management compared with conventional painkillers.

Acetaminophen↗
PubMed1997

Metabolic, biochemical and haemodynamic effects of infusion of propofol for long-term sedation of children undergoing intensive care.

We have studied prospectively, in nine children requiring sedation to facilitate mechanical ventilation, the metabolic, biochemical and haemodynamic effects of infusion of propofol. Children were given infusions of propofol 1-4mg kg-1 h-1 and fentanyl 1-5 micrograms kg-1 h-1 for 48 h. Heart rate, arterial pressure, central venous pressure, fluid balance and urine output were recorded hourly and sedation scores every 4 h. In addition to routine haemodynamic and biochemical measurements in the intensive care, 6-hourly arterial blood-gas analysis and 12-hourly measurements of serum concentrations of glucose, lactate and electrolytes, renal function, triglycerides and liver function tests were performed. Urine was analysed for ketones. There were no significant differences in haemodynamic or biochemical variables during the 48-h period. In this small sample of children, propofol combined with fentanyl provided excellent sedation with no evidence of cardiac, renal or hepatic impairment. Under these very proscriptive conditions we did not encounter lipaemia or acidosis with infusion of propofol. Thus propofol may be a safe sedative agent for use in paediatric intensive care if used appropriately. Further large scale studies are needed to determine if warnings against the use of this agent in paediatric intensive care units are justified.

Acid-Base Equilibrium↗
PubMed1996

Effect of anaesthesia on lung function in children with asthma.

Spirometry was performed before operation, soon after recovery ("early") and the day after ("late") general anaesthesia for elective surgery in 20 children with asthma and 20 matched children without asthma. Pulse oximetry was recorded on the first postoperative night. The mean early peak expiratory flow rate (PEFR) decreased in the asthmatics by 19.91 (95% confidence intervals (CI) 10.84-28.97)% and in the controls by 19.25 (10.70-27.80)%. The mean early FEV1 decreased in the asthmatics by 16.02 (9.29-22.75)% and in the controls by 11.03 (2.86-19.19)%. The mean late decrease from baseline PEFR for the asthmatics was 18.55 (11.23-25.87)% but only 14.93 (7.89-21.97)% for the controls. The mean late FEV1 was 8.2 (0.83-15.56)% below baseline in the asthmatics but only 6.82 (-0.79 to 14.42)% in the controls. There were no differences in overnight pulse oximetry. We conclude that healthy children exhibited a decrease in FEV1 and PEFR after general anaesthesia for elective surgery, but this decline did not appear to be any greater in well controlled asthmatic children compared with children who did not have asthma.

Adolescent↗
PubMed1994

Use of liposuction and saline washout for the treatment of extensive subcutaneous extravasation of corrosive drugs.

We report a case of extensive subcutaneous extravasation of corrosive drugs used during cardiac resuscitation, in a neonate undergoing cardiac catheterization. Early management with hyaluronic acid, liposuction and saline washout of the extravasated fluid prevented development of any tissue damage. This simple technique was easy to use and extremely effective.

Cardiac Catheterization↗
PubMed1994

[Transmission of hepatitis C virus from mother to infant].

The transmission of hepatitis C virus (VHC) by percutaneous exposure to blood contamination is well documented but account for only 50 to 60% of hepatitis C cases. The transmission route for sporadic cases remains controversial and transmission by sexual contact and vertical transmission have been implicated. Antibodies to HCV are detected in 0 to 4.3% of pregnant women varying across geographic regions or origins. Passively transmitted maternal anti-HCV are detected in most of the new-born babies and persist during 6 to 18 months. The estimated risk of vertical transmission varies widely in the literature probably because of methodological considerations. But the detection of HCV-RNA in the blood of children has confirmed vertical transmission of HCV from mother to infant in mothers coinfected or not with human immunodeficiency virus type 1. In case of vertical transmission, some children develop an acute hepatitis or a chronic carrier state with or without chronic liver disease. In this case, the course of HCV RNA and transaminases might reflect the fluctuating viral replication. Some other children, infected at birth, seem to clear the HCV virus. The babies' HCV-antibodies are detected in some infected children but not in all. The follow up of HCV-seropositive pregnant women and their offsprings with more reliable methods should clarify the clinical importance, the rate of transmission and the factors which influence it.

Female↗
PubMed1992

Factors influencing epidural catheter migration.

The incidence and amount of migration of epidural catheters was investigated in a prospective randomised study of 153 women who required analgesia in labour. Inward or outward migration occurred in 36% of patients. Inward migration by 1-3 cm occurred in 21 (13.7%) patients and outward migration by 1 cm or more occurred in 34 (22.2%); three (2%) catheters migrated out through the skin. There were significant positive correlations between outward migration and weight, body mass index, and depth of the epidural space. There was no relationship between migration and height, age, intervertebral space used or duration of catheterisation. Problems with epidural block were no more likely in patients in whom migration of 1 cm or more occurred compared with those in whom migration was limited to a maximum of +/- 0.5 cm. However, the pattern of problems was different. All cases of failed epidural block occurred in patients whose epidural catheter migrated outward by 2.5 cm or more. Unilateral blockade was not more likely if migration of 1 cm or more occurred.

Adhesives↗
PubMed1985

An automatic contact-counter for recording object play.

The paper describes a portable electronic device which automatically records a measure of object play behaviour, by counting the number of contacts made with a play manipulandum. The device is designed for recording a measure of object play in domestic cats, but is readily adaptable for use with other species.

Animals↗