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Biomedical subjects

L Griffin

Publications and source records attributed to L Griffin.

At least 37 records · Page 2Linked to original sources
PubMed1997

Motor unit discharge rate is not associated with muscle relaxation time in sustained submaximal contractions in humans.

The muscle wisdom hypothesis suggests that motor unit discharge rates decrease in parallel with the slowing of muscle contractile properties during fatigue. In this study, the discharge rates of single motor units and the muscle contractile properties were measured during a sustained submaximal contraction. The majority of motor units that were active from the beginning of the task demonstrated a decline in discharge rate in the absence of any slowing of muscle relaxation time. These findings suggest that the muscle wisdom hypothesis may not apply to sustained submaximal contractions.

Adult↗
PubMed1997

The effect on compliance of a health education leaflet in colorectal cancer screening in general practice in central England.

OBJECTIVE: To raise compliance in a general practice based colorectal cancer screening programme by the use of a simple health educational leaflet. DESIGN: A randomised controlled trial of the leaflet's effect on completion of faecal occult blood tests. The leaflet explained the high frequency of colorectal cancer, the principles of screening, and addressed reasons for non-compliance. SETTING: The British town of Market Harborough where most of the population are registered with a single practice. PARTICIPANTS: These comprised 1571 residents aged 61 to 70 years registered with the practice. Residents were invited to receive a free faecal occult blood test in a colorectal cancer screening programme. Half the population were randomly assigned to receive the educational leaflet about screening. RESULTS: Compliance in test and control groups, positive rate of stool testing, and pathology detected were measured. Compliance was higher in men who received the leaflet in those aged 61 to 65 years (36% v 27%, chi2 = 4.0, p < 0.05) and in men aged 66 to 70 years (39% v 23%, chi2 = 9.7, p < 0.01). In women, use of the leaflet did not affect compliance in those aged either 61 to 65 years (38% v 36%, chi2 = 0.1, NS) or 66 to 70 years (31% v 31%, chi2 = 0.0, NS). The positive rate of stool testing in patients observing the required dietary restrictions was 1.6%. A significant lesion was detected in 1.4% of people tested (2 carcinomas and 5 patients with adenomatous polyps). CONCLUSIONS: Health education leaflets addressing reasons for non-compliance significantly increased compliance in men and should be used in screening programmes. Reasons for the lack of success of the leaflet in women should be investigated and other interventions for raising compliance should be developed.

Aged↗
PubMed1997

Is ultrasonography a reliable way to confirm the diagnosis of Morton's neuroma?

The diagnosis of Morton's neuroma is based on patient history and clinical findings. Occasionally, however, the diagnosis still remains in doubt despite careful examination. While magnetic resonance imaging (MRI) has been used to evaluate such cases, its specificity remains unproven and its availability is not universal. Ultrasonography may offer a reasonable alternative to MRI. Eight patients clinically diagnosed with neuromas who had not responded to conservative care underwent ultrasonography. Sonography in each demonstrated a round or oval echogenic mass where a neuroma was believed to be present. Sonography on a control group of 10 asymptomatic patients (20 feet) revealed no such mass. Pathologic inspections of surgically resected specimens confirmed the diagnosis of Morton's neuroma. With no false positive results, this preliminary study indicates ultrasonography may be a specific diagnostic test for Morton's neuroma.

Adult↗
PubMed1996

Calcium buffering is required to maintain bone stiffness in saline solution.

This work determined whether mineral dissolution due to prolonged testing or storage of bone specimens in normal saline would alter their elastic modulus. In one experiment, small pieces of equine third metacarpal bone were soaked in normal saline supplemented with varying amounts of CaCl2. Changing Ca ion concentrations in the bath were monitored and the equilibrium concentration was determined. In a second experiment, the elastic moduli of twenty 4 x 10 x 100 mm equine third metacarpal beams were determined non-destructively in four-point bending. Half the beams were then soaked for 10 days in normal saline, and the other half in saline buffered to the bone mineral equilibrium point with Ca ions. Modulus measurements were repeated at 6 and 10 days. The equilibrium Ca ion concentration for bone specimens was found to be 57.5 mg l-1. The modulus of bone specimens soaked in normal saline significantly diminished 2.4%, whereas the modulus of those soaked in calcium-buffered saline did not change significantly.

Animals↗
PubMed1996

Pharmacokinetics, bioavailability, metabolism, and tissue distribution of cidofovir (HPMPC) and cyclic HPMPC in rats.

The pharmacokinetics, distribution, and metabolism of [14C]cidofovir and its cyclic analog {[2-14C]-1-[((S)-2-hydroxy-2-oxo-1,4, 2-dioxaphosphorinan-5-yl)methyl]cytosine; [14C]cyclic HPMPC} were compared after administration to Sprague-Dawley rats. After intravenous (iv) administration of [14C]cidofovir (3 or 5 mg/kg) or [14C]cyclic HPMPC (5 mg/kg), plasma concentrations of total radioactivity declined in a multiexponential manner for both drugs with terminal half-lives of 7-11 hr. No metabolites of cidofovir were observed in plasma. However, iv [14C]cyclic HPMPC was converted in vivo to cidofovir (3.9% of the AUC of total radioactivity). The corrected half-life of cyclic HPMPC was 0.53 +/- 0.05 hr. The clearance of iv cidofovir (0.60-0.79 liter/hr/kg) was significantly less than that of cyclic HPMPC (1.10 +/- 0.12 liter/hr/kg). Cyclic HPMPC was more efficiently secreted by the kidney than cidofovir. The steady-state volume of distribution of cyclic HPMPC (0.32 +/- 0.5 liter/kg) was substantially less than that of cidofovir (0.9-3.0 liter/ kg). Concentrations in kidney at 24 hr after iv administration of 5 mg/kg were approximately 20-fold higher for cidofovir (6.6 micrograms-eq/g) than for cyclic HPMPC, whereas levels of radioactivity in the remaining tissues were similar for both drugs. This is consistent with the improved therapeutic index observed for cyclic HPMPC in animals. After iv administration of [14C]cidofovir (3 mg/kg), concentrations in most tissues declined with half-lives > 12 hr, presumably reflecting the long intracellular half-life of phosphorylated drug. Kidneys and liver of animals given iv [14C]cidofovir (5 mg/kg) contained unchanged cidofovir (35-65%), metabolite I (attributed to cidovofir phosphocholine) (29-60%), and a peak coeluting with cyclic HPMPC on three different HPLC systems (metabolite II) (5-7%). Kidneys, liver, and lung of animals given iv [14C]cyclic HPMPC contained cyclic HPMPC (1-6%), cidofovir (44-50%), and metabolite I (44-54%). The subcutaneous bioavailability of cidofovir was 91.5%. The subcutaneous and oral bioavailabilities of cyclic HPMPC were 82.7% and 3.50 +/- 1.07%, respectively, based on total radioactivity.

Administration, Cutaneous↗
PubMed1991

Porin interaction with hexokinase and glycerol kinase: metabolic microcompartmentation at the outer mitochondrial membrane.

Porin is the pore-forming protein involved in the movement of adenine nucleotides across the outer mitochondrial membrane (OMM). Hexokinase and glycerol kinase interact with porin on the outer surface of the OMM in a manner which provides these enzymes with preferred access to the ATP generated in the mitochondrion. We review recent evidence which permits refinement of our knowledge of these proteins and their interactions at the OMM. The involvement of this system in metabolic microcompartmentation is discussed, as well as possible pathological consequences of its disruption in malignancy and genetic deficiencies of hexokinase, glycerol kinase, and porin.

Adenine Nucleotides↗
PubMed1986

Bipolar fixation of fractures of the distal radius: preliminary results.

Twenty-eight unstable distal fractures of the radius have been treated with pins incorporated into a forearm plaster. The wrist is maintained in a neutral position permitting early use of the hand. Secondary displacement has been decreased. It is a safe and effective method of treating unstable distal fractures of the radius suitable for regular use in a busy district general hospital without the need of expensive specialized equipment.

Casts, Surgical↗
PubMed1983

Congenital transmission of Trypanosoma congolense in mice.

Pregnant mice were infected with a strain of T. congolense which produces a chronic infection, to determine if congenital infection can occur. Some of the mice were killed before delivery and tissues of foetuses injected into clean male mice. Other mothers were allowed to deliver and the tissues of some of the 1-day-old young inoculated into male mice while the remaining members of each litter were suckled by the infected mother until weaning. Some but not all males infected from foetuses and 1-day-old young became infected, while the litter-mates suckled normally by their mothers did not show any infection. It seems that T. congolense, though not commonly found in tissues of the host, can cross the placental barrier and infect the foetus, but that young suckled by infected mothers may be protected from infection.

Animals↗
PubMed1983

Serological and parasitological survey of blood donors in Kenya for toxoplasmosis.

322 samples of sera from blood donors in four areas of Kenya were screened for Toxoplasma gondii antibodies by haemagglutination and 54% proved positive. 299 of these were also tested by dye test and 42% were positive, with 5.9% showing high titres indicating possible active infection. Parasitological examination of the buffy coat from donors was also carried out on 100 samples but no Toxoplasma parasites were seen in spite of high antibody incidence. There appears to be little or no clinical toxoplasmosis in Kenya but serological studies indicate a widespread distribution of the parasite in the human population.

Adolescent↗
PubMed1983

The frequency of psychiatric disorders among patients attending semi-urban and rural general out-patient clinics in Kenya.

The prevalence of psychiatric morbidity (PM) was studied among general hospital out-patients in a rural and in a semi-urban area of Kenya. There were no significant differences in the demographic features of psychiatric patients from the two areas, so the results were pooled: this gave a PM prevalence rate of 29 per cent among 388 patients. Anxiety and depression were the most frequent diagnostic categories. Alcoholism was more common in the rural than in the semi-urban area. There was no sex difference in the prevalence of PM and possible reasons for this, which is in contrast to western findings, are discussed. Psychiatric symptoms could be readily elicited when present. Patients showing them had been ill longer than non-PM patients. The study suggests that clinic staff not psychiatrically trained should be able to identify and treat psychiatric morbidity, even when it is presented as somatic illness.

Adolescent↗
PubMed1982

Does Pneumocystis carinii occur in Kenya?

An experiment was carried out exposing immunosuppressed mice to the atmosphere to determine if transmission of Pneumocystis carinii occurred in Kenya. Mice were killed at weekly intervals for four months and the lungs examined histologically for the presence of these parasites. None of the mice contracted even light infections and this, together with the lack of clinical evidence of this disease in immunosuppressed or neonatal cases, suggests that this parasite does not occur in Kenya. Possible reasons for this are discussed.

Animals↗