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Biomedical subjects

J M Hunter

Publications and source records attributed to J M Hunter.

At least 55 records · Page 3Linked to original sources
PubMed1996

Reconstruction of the transverse carpal ligament to restore median nerve gliding. The rationale of a new technique for revision of recurrent median nerve neuropathy.

Two clinical and four surgical steps can be taken to return gliding and nutritional balance to the median nerve after revision surgery for a recurrent median nerve neuropathy: Step One (Clinical): An accurate diagnosis of the median nerve traction neuropathy. Consider brachial plexopathy and terminal neuropathies. Step Two (Surgical): Comprehensive exploration and meso-epineurolysis of the median nerve from the radial remnants of the divided TCL and fibrosed radial and ulnar bursae by resection of the bursae and flexor tenosynovectomy. Step Three (Surgical): Fasciotomy of the volar carpal ligament to lengthen the ulnar leaf of the TCL; permits visualization of the ulnar artery and neurolysis of the ulnar motor nerve. Step Four (Surgical): Mobilize the previously released radical leaf TCL and motor median nerve from the origin of the thenar muscles. Step Five (Surgical): Restore the inner gliding surface and strength of the flexor retinaculum of the hand and wrist by reconstruction of the TCL and the forearm antebrachial fascia. Step Six (Clinical): An immediate postoperative hand therapy program to restore gliding to the median nerve and flexor tendons. Protocols for upper extremity nerve gliding should be carried out under supervision at selected daily intervals. A prevailing brachial plexopathy requires positive supervised therapy for nerve gliding and posture control.

Carpal Tunnel Syndrome↗
PubMed1996

Prevalence of hypertension among women in rural Zimbabwe: a comparison of pregnant and non-pregnant women.

OBJECTIVES: To determine the prevalence of pregnancy induced hypertension (PIH) in rural Zimbabwe. DESIGNS: A blood pressure survey conducted in three socio-economic strata of rural Zimbabwe, communal lands, commercial farms and mining areas. SETTING: Rural Zimbabwe, Mashonaland West Province. SUBJECTS: 627 pregnant (> 20 weeks gestation) and 483 non pregnant (ages 16 to 45) women. MAIN OUTCOME MEASURE: Prevalence of PIH. RESULTS: PIH was defined in two ways: 1. A combination of > or = 2+ proteinuria and systolic and/or diastolic pressure > or = SD above the mean for all pregnant women (> or = 123/75 mmHg). 2. > or = 1+ proteinuria and blood pressure of 140 and/or 90 mmHg. Eight women met definition 1 and seven met definition 2, giving a prevalence of 0.8pc; 1.3pc and 3.2pc in communal lands, commercial farms and mines respectively. In non-pregnant women the prevalence of hypertension (> or = 160 and/or 95 mmHg) was 3.5pc; 5.4pc and 15.1pc in communal lands, commercial farms and mines respectively. CONCLUSION: PIH is rare in rural Zimbabwe. Hypertension among non-pregnant women of child bearing age is most common in mining communities which have many similarities to urban environments.

Adolescent↗
PubMed1995

New neuromuscular blocking drugs.

The new nondepolarizing neuromuscular blocking drugs have specific advantages over succinylcholine. Rocuronium has an onset of action that is almost as rapid as that of succinylcholine and may be useful in patients with residual gastric contents. This drug may replace vecuronium, since the two agents are otherwise similar. The onset of action of mivacurium is similar to that of atracurium, but recovery from the blockade is more rapid (if the plasma cholinesterase level is normal), making mivacurium useful for short procedures. Although pipecuronium and doxacurium have minimal effects on the cardiovascular system, their long and variable onset and duration of action limit their usefulness. The need for either drug is questionable. There is still a need, however, for a nondepolarizing drug that has an onset of action as rapid as that of succinylcholine but a duration of action similar to that of mivacurium, with no adverse cardiovascular effects and clearance from the body that is independent of organ function.

Aged↗
PubMed1995

Paradise lost: an introduction to the geography of water pollution in Puerto Rico.

Rapid industrialization has transformed the agricultural economy of Puerto Rico, creating employment opportunities and raising standards of living. Success, however, is marred by widespread pollution that outstrips the infrastructural capacity necessary for the preservation of environmental quality and of human health. The result today is a landfill crisis, a heritage of toxic dumps, and an advancing tide of pollution. Rivers and reservoirs are nearly ubiquitously affected and groundwaters, long thought to be naturally protected, show evidence of increasing contamination. Limestone aquifers are at particular risk. Public awareness and inter-sectoral political leadership are urgently needed to reverse the trend towards environmental deterioration.

Developing Countries↗
PubMed1995

The tooth as a marker of developing world quality of life: a field study in Guatemala.

A geographical sample in a rural area of eastern Guatemala revealed widespread, premature and heavy losses of permanent teeth. Social and environmental influences that affect tooth loss include inadequate diet, refined sugar, poor oral hygiene, absence of fluoride, lack of preventive education and insufficiency of dental care services. Land hunger and family poverty are of paramount importance. Gender-based cultural differences are apparent in tooth extraction rates, and use of dentures. No one escapes visitations of severe orofacial pain that cast a blight upon the quality of rural life. Periodontal disease drives the poorest of the poor to spend disproportionately large sums on pharmaceutical pain-killers and destructive traditional medicines. Lay 'tooth-pullers' visit remote rural homes to extract teeth. Only full edentulism can bring patients permanent somatic and financial relief. Community dental health is conspicuously neglected in official policies and plans for rural development.

Adolescent↗
PubMed1995

Pharmacodynamics of the 1R cis-1'R cis isomer of atracurium (51W89) in health and chronic renal failure.

We have studied the pharmacodynamics of the 1R cis-1'R cis isomer of atracurium (51W89) in 15 healthy subjects and in 17 patients with chronic renal failure using a bolus dose of 51W89 0.1 mg kg-1 (2 x ED95). Fifteen patients with normal renal function were investigated also using an approximately equipotent dose of atracurium (0.4 mg kg-1). The compound surface action potential of the adductor pollicis muscle, in response to train-of-four stimulation of the ulnar nerve at the wrist, was recorded until recovery of the height of the first response of the train-of-four compared with baseline (T1:T0) had reached at least 85% and the train-of-four ratio (T4:T1) at least 80%. In the healthy and renal failure patients who received 51W89, there were no significant differences in any of the onset or recovery variables except for the time to 90% depression of T1:T0, which was longer in patients with renal failure (mean 3.7 min vs 2.4 min; P < 0.05). Of the healthy patients who were given either 51W89 or atracurium, there were no significant differences in the onset data, except for time to maximum block, which was longer in the 51W89 group (mean 7.7 min vs 6.2 min; P < 0.01). The mean times to 10%, 25%, 50% and 75% recovery of T1:T0 and the time for T4:T1 > 70% were significantly longer in patients receiving 51W89.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1995

Pharmacokinetics and pharmacodynamics of the three isomers of mivacurium in health, in end-stage renal failure and in patients with impaired renal function.

We have studied the pharmacokinetics of cis-trans, trans-trans and cis-cis mivacurium in nine healthy patients (creatinine clearance 66-133 ml min-1), in seven patients with end-stage renal failure requiring dialysis (creatinine clearance 4-11 ml min-1) and in seven patients with impaired renal function (creatinine clearance 32-49 ml min-1), during thiopentone-fentanyl-midazolam-nitrous oxide-oxygen anaesthesia. Mivacurium chloride was infused at a rate of 15 micrograms kg-1 min-1 for 10 min, 7.5 micrograms kg-1 min-1 for a further 10 min, and then at a rate adjusted to maintain T1/T0 at 5%. The minimum duration of infusion was 60 min (range 60-235 min). The plasma concentration of the three isomers was measured at regular intervals throughout the infusion, and for up to 300 min after the infusion was stopped. Compartmental analysis of the resulting isomer profiles was undertaken: one- and two-compartment models were fitted to derive clearance, volume of distribution and terminal elimination half-life. Clearance of the cis-cis isomer was reduced significantly in the renal failure (median 2.4 (range 2.1-2.6) ml kg-1 min-1) and intermediate renal function groups (2.1 (2.0-2.9) ml kg-1 min-1), compared with healthy patients (3.8 (2.6-4.9) ml kg-1 min-1) (P < 0.01 in each case).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Pharmacokinetics of 1R-cis 1'R-cis atracurium besylate (51W89) and plasma laudanosine concentrations in health and chronic renal failure.

To ascertain the effects of chronic renal failure on the pharmacokinetics of 1R-cis 1'R-cis atracurium besylate (a stereoisomer, designated 51W89), we gave a bolus dose of 0.1 mg kg-1 (2 x ED95) to 17 patients with end-stage renal failure and to 15 patients with normal renal function undergoing elective surgery. All patients received thiopentone, fentanyl and midazolam i.v. and 70% nitrous oxide in oxygen. Blood samples were obtained over 8 h and plasma analysed for 51W89 and laudanosine concentration, using high pressure liquid chromatography. A two-compartment model was fitted to the 51W89 plasma concentration data using the NONMEM program, to estimate pharmacokinetic variables and to determine the influence of renal failure, age, weight and sex. Clearance of 51W89 was found to be reduced by 13% in renal failure. The typical value of T1/2 beta was 4.2 min longer in renal failure than in the healthy patients (34.2 vs 30.0 min, P < 0.005). In the healthy patients, clearance of 51W89 was greater in males, but it decreased with increasing age by approximately 1.5 ml min-1 yr-1. Mean plasma laudanosine concentrations were significantly higher in the renal failure group; nevertheless, they were approximately one-tenth of those reported after atracurium.

Adult↗
PubMed1995

Pharmacokinetics of 51W89: preliminary data.

The pharmacokinetics of the 1R cis-1'R cis-isomer of atracurium (51W89) and its metabolite, laudanosine, were studied in 11 healthy patients with normal renal function and in 12 patients with chronic renal failure undergoing regular dialysis. A bolus dose of 51W89 (0.1 mg/kg) was given, and the plasma concentration was measured at regular intervals for 480 min. The elimination half-life of 51W89 was significantly longer in renal failure patients than in healthy controls (38.9 min vs 30.6 min; P < 0.05). The plasma laudanosine levels were lower than those reported after an equipotent dose of atracurium besylate. 51W89 may have a prolonged effect in renal failure patients.

Atracurium↗
PubMed1995

The pharmacokinetics of rocuronium bromide in hepatic cirrhosis.

The pharmacokinetics of aminosteroid neuromuscular blocking drugs have been shown to be altered in patients with hepatic cirrhosis. A reduced clearance and prolonged elimination half-life of pancuronium and vecuronium have been demonstrated. Pharmacokinetic studies of the newest aminosteroid neuromuscular blocking agent, rocuronium, performed in a small number of cirrhotic patients, have proved inconclusive, apart from noting a higher central volume of distribution than in healthy patients. This difference may result in a slightly delayed onset of neuromuscular block. Nevertheless, rocuronium, even in cirrhotic patients, has the fastest onset of action of any non-depolarizing neuromuscular blocking agent. Further pharmacokinetic studies are necessary of this drug in hepatic cirrhosis.

Androstanols↗
PubMed1994

Pharmacokinetics of the three isomers of mivacurium and pharmacodynamics of the chiral mixture in hepatic cirrhosis.

We have studied the pharmokinetics of cis-trans, trans-trans and cis-cis mivacurium in 10 healthy subjects and 11 patients with mild or moderate hepatic cirrhosis, during nitrous oxide-oxygen-isoflurane anaesthesia. Mivacurium 15 micrograms kg-1 min-1 was infused for 10 min (total dose 0.15 mg kg-1) and the plasma concentration of the three isomers measured at regular intervals for 190 min. The electromyographic response to the drug was also measured. Compartmental analysis of the resulting isomer profiles was undertaken: one- and two-compartment models were fitted to derive clearance, volume of distribution and half-life. Clearance of the cis-trans and trans-trans isomers was reduced significantly in the cirrhotic compared with the healthy group: cis-trans (median (range)) 44 (15-121) ml kg-1 min-1 vs 95 (57-213) ml kg-1 min-1 (P < 0.05); trans-trans 32 (12-64) ml kg-1 min-1 vs 70 (34-101) ml kg-1 min-1 (P < 0.05). The difference in the clearance of the cis-cis isomer in the cirrhotic (4.2 (2.9-12.1) ml kg-1 min-1) compared with the healthy group (5.2 (2.9-8.9) ml kg-1 min-1) was not significant with this sample size. Clearance of each isomer correlated significantly with plasma cholinesterase activity: cis-trans r = 0.73, P < 0.001; trans-trans r = 0.69, P < 0.001; cis-cis r = 0.48, P < 0.05.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Muscle relaxants in renal disease.

The use of neuromuscular blocking drugs during anaesthesia for patients with chronic renal failure is discussed. The disadvantages of the older non-depolarizing agents, such as tubocurarine, alcuronium, and pancuronium are outlined, as are the significant benefits of the use of atracurium or vecuronium in these patients. Preliminary reports on the new non-depolarizing drugs, pipecuronium, mivacurium, doxacurium, and rocuronium are also noted.

Anesthesia↗
PubMed1993

Effect of age, gender and anaesthetic technique on the pharmacodynamics of atracurium.

We have measured in 38 patients the plasma concentration profile of atracurium and its effect on the electromyographic first response of the train-of-four. One of three techniques was used to supplement anaesthesia with 66% nitrous oxide in oxygen, 0.9% isoflurane (end-tidal), 0.5% halothane (end-tidal) or midazolam 3-10 mg. A four-parameter threshold pharmacodynamic model was fitted to the data in each patient. Compared with a group of patients anaesthetized with an i.v. technique, the steady-state plasma concentration producing 50% block (Cpss50) was reduced by halothane, and to a greater extent by isoflurane. The rate constant for exit from the effect compartment (k(eo)) correlated negatively with age and was greater in female patients, but unaffected by anaesthetic technique. The values of gamma, the slope of the concentration-response curve, and of the threshold (Cpss theta) were not affected significantly by age, sex or anaesthetic technique.

Adolescent↗