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Biomedical subjects

J Leach

Publications and source records attributed to J Leach.

At least 37 records · Page 2Linked to original sources
PubMed1988

Regionally variable pulmonary artery responses to C3a.

Products of the complement (C) cascade may have direct effects on pulmonary vascular tissue and contribute to pulmonary vasoconstriction in states of C activation. We studied the effects of C3a, a C-derived vasoactive peptide, on isolated rabbit hilar (HPA) and main pulmonary arteries (MPA). C3a elicited concentration-dependent constriction of HPA (10(7) M to 5 x 10(7) M) but minimal response in MPA at all concentrations tested. The difference between HPA and MPA responses was significant (P less than 0.05, paired t test). To evaluate HPA desensitization to C3a, the peptide was reapplied at 60 min in some tissues and at 120 min in others. All tissues consistently exhibited less constriction at 60 min than observed with previous exposures. Histamine contribution to the HPA response to C3a was determined by exposing the tissues for 30 min before C3a application to pyrilamine (1 x 10(-5) M), an histamine H1-receptor antagonist. Pyrilamine reduced the HPA response to C3a by 70-85%. We conclude that 1) isolated rabbit PA responses exhibit regional variability to C3a over a range of concentrations; 2) C3a desensitizes HPA for at least 60 min, but the tissue demonstrates variable recovery within 120 min; and 3) HPA responses to C3a are reduced by pyrilamine, an H1-receptor antagonist.

Animals↗
PubMed1987

Recombinant DNA in filamentous fungi: progress and prospects.

Recombinant DNA technology enables the creation of well-defined alterations in the genetic material of an organism. Methods to manipulate recombinant DNA in the filamentous fungi (a group of microorganisms that includes species of academic as well as commercial interest) have recently been developed. This has been the result of adaptation of procedures successfully employed in the manipulation of other microorganisms. There are a number of similarities in the behavior of recombinant DNA in different fungi, but a number of differences have also been observed between the filamentous and the nonfilamentous fungi. Such differences include the ability to identify DNA replication origins and the host range of expression of fungal genes.

Cloning, Molecular↗
PubMed1987

Nonunion following two-level anterior cervical discectomy and fusion.

Nonunion is a potential complication of anterior cervical discectomy and fusion (ACDF). There are reports that cite the prevalence of nonunion for two-level ACDF with various fusion techniques, but they do not recommend treatment alternatives. Pseudarthrosis after a two-level ACDF occurred in a 69-year-old man. Posterior cervical wiring and autograft resulted in a successful fusion anteriorly and posteriorly. Posterior fusion augments stability, enhances the potential for eventual anterior fusion, avoids the risks of an additional anterior procedure, and is an excellent therapeutic alternative to a second anterior attempt at stabilization.

Aged↗
PubMed1986

Foot deformities in infants and children.

Foot deformities may reflect a generalized disorder, especially a neurologic problem; thus, the child should have a brief general examination. Many infantile foot deformities, such as calcaneovalgus, are postural and self-correcting. Metatarsus varus is not referred for treatment until age 2 months and then only if the deformity is moderate or severe. Fixed forefoot equinus and heel varus characterize a clubfoot, which requires immediate treatment. Corrective shoes are not advised as the primary treatment for metatarsus varus or clubfoot but often are prescribed to maintain the corrected position after serial casts. Flexible flatfoot is a manifestation of a constitutional laxity affecting all ligaments and joints. The feet appear abnormal because of weight-bearing stresses. Most children with flatfoot achieve a partial correction spontaneously. Current research does not document that treatment with corrective shoes or inserts produces a result better than the partial correction that occurs naturally.

Clubfoot↗
PubMed1984

Occupational exposure to chlorophenates: toxicology and respiratory effects.

We have identified 71 chlorophenate-exposed sawmill workers as part of a group undergoing an extensive health and environmental evaluation in a pulp mill. We have compared this group with a group (351) with no physical proximity to the area in which chlorophenates were used. We demonstrated a gradient of exposure from 230 ppb in urine and 919 ppb in serum for those directly handling the contaminated wood, to 139 ppb in urine and 354 ppb in serum for those working in the area but not in manual contact as compared with serum levels of 84 ppb in the unexposed group. We noted that the bulk chemical was primarily in the tetrachloro-form but the serum levels contained more pentachlorophenate. The urine proportions were intermediate, approximating the bulk chemical proportions at the lower levels of exposure. We did not find an excess prevalence of respiratory symptoms or spirometric abnormalities which could be explained by the chlorophenate exposure.

Adult↗
PubMed1983

Correlation of scoliosis and pulmonary function in Duchenne muscular dystrophy.

Pulmonary function was correlated with patient age and degree of thoracic scoliosis in 25 patients with Duchenne muscular dystrophy in a retrospective, longitudinal study. The observed forced vital capacity (FVC) was found to peak at approximately the age when standing ceases, then to decline rapidly. Thoracolumbar curves were found to be insignificant in adversely affecting pulmonary function in patients with Duchenne muscular dystrophy. Percent FVC was found to be the parameter of pulmonary function that was most strongly correlated with age and scoliosis measurements. In addition, age and thoracic scoliosis together were better predictors of percent FVC than either one alone. Each 1 year of age had approximately the same negative influence on percent FVC that each 10 degrees of thoracic scoliosis had; both decreased percent FVC by approximately 4%. A regression equation for percent FVC is presented which predicts that the patient who has had scoliosis progression halted by spinal fusion would, subsequent to the surgery, show a slower rate of decline of percent FVC and that this rate is quantifiable, predictable, and dependent solely on the patient's advancing age. Therefore, early spinal instrumentation and fusion is advocated in the patient with Duchenne muscular dystrophy.

Adolescent↗
PubMed1981

The pathomechanics of gait in Duchenne muscular dystrophy.

Forty-six separate gait studies were analysed for 21 ambulatory patients with Duchenne muscular dystrophy. Three groups were defined on the basis of significant gait variables: early, transitional and late. Disease progression can be predicted with 91 per cent accuracy by three gait variables: cadence, dorsiflexion in swing, and anterior pelvic tilt. The patients in the early group manifested a positive Gower's sign but gait changes were subtle, being principally slightly increased hip flexion in swing, decreased dorsiflexion in swing and reduction in cadence. The force line moved in front of the knee center early in single-limb support. In the transitional stage, anterior pelvic tilt was exaggerated, cadence was further reduced, and foot drop in swing phase was increased. Shoulder sway was noted as a compensation for gluteus medius weakness. The base of support widened. The force line remained behind the hip joint and in front of the knee joint throughout single-limb support. In the late stage, work output increased, cadence continued to drop, shoulder sway increased further, and there was a wider base of support. The force line remained very close to the center of the hip and in front of the knee at all times during single-limb support. The authors' conclusions are: (1) the earliest postural change in gait is increased lumbar lordosis secondary to gluteus maximus weakness, and at this time the quadriceps are relatively competent; (2) quadriceps insufficiency was the key factor in gait deterioration. It appeared in the transitional stage and was characterized by exaggerated anterior pelvic tilt, restricted hip extension in stance phase, equinus posturing, and maintenance of the force line in front of the knee throughout single-limb support. Long-leg bracing is indicated when these signs of quadriceps insufficiency are noted.

Biomechanical Phenomena↗
PubMed1978

The effectiveness of a service for helping destitute men.

The effectiveness of a voluntary organization which aimed to help destitute men contacted by means of a 'soup run' was evaluated. The assessment was carried out in stages. At the end of each stage results were discussed with the organization and a set of recommendations for further action put forward. At the end of the first stage, it was agreed that the organization's aim should be restricted to attempting to help men settle in one of its houses (staffed by young volunteer workers) for a period of at least three months. A number of recommendations intended to achieve this result were unsuccessful. Following the setting up of a night shelter, it was observed that many men attended regularly. An assessment procedure was instituted which resulted in the selection of men who did settle in the houses for long periods, so much so that no further admissions became possible.

Cultural Deprivation↗