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Biomedical subjects

S H Moss

Publications and source records attributed to S H Moss.

At least 37 records · Page 2Linked to original sources

Photoreactivation in phr mutants of Escherichia coli K-12: cloning from the gal-att lambda interval increases the photoreactivable response in phrA strains.

In this report we have cloned restriction fragments from the gal-att lambda region obtained from a purified preparation of lambda dgal transducing 'phage DNA, and demonstrate the appearance of a photoreactivable response in a photoreactivation-deficient phrA phrB strain. We also show that when this plasmid is transduced into a delta phrA strain there is an increase in the photoreactivable response after a single high intensity light flash and after continuous illumination. These data have been discussed in relation to the hypothesis of the presence of multiple photolyase molecules in Escherichia coli.

Bacteriophage lambda↗

Effects of peroxide and catalase on near ultraviolet radiation sensitivity in Escherichia coli strains.

The role of peroxide and catalase on NUV radiation sensitivity was examined in two repair competent E. coli strains, AB1157 and B/r. Exponential phase B/r is considerably more sensitive to NUV radiation than exponential phase AB1157. However, resistance to 5 mmol dm-3 H2O2 was induced in both AB1157 and B/r by pretreating growing cells with 30 mumol dm-3 H2O2. Pretreatment also induced resistance to broad-band NUV radiation in these strains. The addition of catalase to the post-irradiation plating medium increased survival to the same extent as that provided by pretreatment with 30 mumol dm-3 H2O2, in both strains. The NUV radiation sensitivity seen in B/r does not appear to be due to a deficiency in enzymes that scavenge H2O2, as a catalase deficient mutant, E. coli UM1, is more resistant to NUV radiation than B/r. Also, assays for H2O2 scavenging ability show little difference between AB1157 and B/r in this respect. Two hypotheses are put forward to account for the sensitivity of exponential phase B/r. Whilst it is apparent that peroxides and catalase do have a role in NUV radiation damage, it is clear that other factors also influence survival under certain conditions.

Catalase↗

The sensitivity of an actinic reticuloid cell strain to near-ultraviolet radiation and its modification by trolox-C, a vitamin E analogue.

Near-UV radiation (365 nm)-induced lethality, as measured by colony-forming ability, showed an actinic reticuloid cell strain to be sensitive relative to normal human fibroblasts, when irradiated at 25 degrees C. This effect was not seen after far-UV (254 nm) irradiation. Trolox-C, a water-soluble analogue of vitamin E, incorporated in the pre-irradiation growth medium or in the post-irradiation plating medium, protected the actinic reticuloid cells to the extent that they were as resistant as normal cells. Plating medium containing Trolox-C did not provide differential protection against inactivation of the two cell strains by wavelengths in the far-UV region. The protection provided by Trolox-C, an analogue of the natural antioxidant vitamin E, suggests some free radical involvement in the aetiology of the disease.

Antioxidants↗

Effect of growth temperature on lipid composition and ultraviolet sensitivity of human cells.

Human skin fibroblasts were incubated at either 25 or 37 degrees C before UV irradiation. Cells incubated at 25 degrees C were more resistant to near UV radiation than cells grown at 37 degrees C, but cells grown at the lower temperature were more sensitive to 254 nm radiation. Fatty acid analysis of membranes of cells showed that cells incubated at the lower temperature contained significantly higher amounts of linoleic acid (18:2) and linolenic acid (18:3) than cells incubated at 37 degrees C. To determine if this difference in fatty acid content of the membranes was responsible for the UV survival characteristics of cells incubated at different temperatures, cells were enriched with either linoleate or linolenate during a 37 degrees C incubation period. Gas chromatography revealed that cells incorporated the supplied fatty acid. Fatty acid enriched cells were then irradiated with near UV, and survival characteristics were compared to those obtained with cells grown at the lower incubation temperature. The results suggest that the different proportion of fatty acid content of the cells is not the cause of different UV sensitivities of cells grown at 25 degrees C compared to cells grown at 37 degrees C.

Cell Division↗

Scaphoid implant resection arthroplasty. Long-term results.

A silicone scaphoid implant was developed in 1967 to help improve the results of simple resection arthroplasty in the treatment of arthritic changes associated with advanced scaphoid disease. Patients who had scaphoid implant surgery since 1967 were studied. Preoperative and postoperative roentgenograms, charts, surgical pathology, and clinical evaluations were reviewed. A total of 55 cases of scaphoid implant arthroplasty were evaluated. A classification system was developed based on progressive severity, and treatment recommendations were developed for each stage of disease progression. Cystic and degenerative changes in contiguous carpal bones were evaluated. No evidence of cystic change could be found in 37 wrists, minimal changes were found in 9, moderate changes in 5, and severe changes in 4. There were no implant infections or fractures. Implant rotation occurred in two cases. Functional use of the hand with decreased pain was observed. It is important to detect and treat carpal instability, which may be associated with scaphoid disease. Cystic formation can be minimized by avoiding oversized implants, treating the associated carpal instability, bone-grafting preexisting cysts, and avoiding Kirschner wire fixation. By following treatment protocols as established in the classification system, the scaphoid implant can be successfully used in the management of scaphoid pathology.

Adult↗

Digital venous anatomy.

The veins of the digits and their valves were studied in nine cadaveric hands by sequential angiography, microdissection, routine histology, cross-sectional microradiography, and corrosion casting. The findings revealed a pattern of dorsal venous arches situated over each digit. Connections between those arches were at the level of the metacarpal heads, the point at which most of the palmar venous blood joins the dorsal system by intercapitular veins. A system of valves, which were arranged so as to direct flow from distal to proximal, from palmar to dorsal, and from radial to ulnar in the hand, was present in all veins as far distal as the pulp.

Fingers↗

The response of normal and ataxia-telangiectasia human fibroblasts to the lethal effects of far, mid and near ultraviolet radiations.

The responses of two ataxia-telangiectasia (A-T) cell strains to the lethal effects of monochromatic far, mid and near ultraviolet radiations have been determined and compared with the responses of three normal human cell strains. Our results confirm a previous observation that the A-T cell strain AT4BI is abnormally sensitive to the lethal effects of mid u.v. (313 nm) radiation. After far u.v. (254 nm) radiation the strain AT4BI exhibits a small but statistically significant increase in sensitivity compared to the normal strains. Of most interest, in terms of a mechanistic interpretation of the sensitivity of A-T strains, the survival responses of neither A-T strain tested to near u.v. (365 nm) radiation differed significantly from the mean response of the normal strains, although it is of interest that one normal strain (48BR) was found to be significantly more resistant to near u.v. radiation than any of the other strains tested. The results are discussed in terms of the possible induction of radiogenic lesions in DNA by ultraviolet radiations and the possible mechanisms of radiation sensitivity in ataxia-telangiectasia.

Ataxia Telangiectasia↗

Unicompartmental and bicompartmental arthroplasty of the knee with a finned metal tibial-plateau implant.

We followed a series of ten patients (ten knees) who had a unicompartmental and twenty patients (twenty-two knees) who had a bicompartmental arthroplasty of the knee, in which a finned metal tibial-plateau implant had been used, for two to fourteen years (average, five years) postoperatively. According to the modified criteria of MacIntosh and Hunter, thirty knees (94 per cent) had a good result and two (6 per cent), a fair result. There were two complications: one intraoperative and one postoperative fracture of the tibial plateau. One patient with rheumatoid arthritis required a revision to a total knee arthroplasty at six months because of rapid progression of disease in the contralateral, untreated compartment. Our results suggest that with the proper indications this arthroplasty has a place in reconstructive surgery of the arthritic knee joint.

Adult↗

Radial tunnel syndrome: a spectrum of clinical presentations.

A variety of symptoms associated with 15 cases of resistant tennis elbow and resistant radial tunnel pain are described. These included sensations of popping, paresthesias, and paresis. The duration of symptoms averaged 2.3 years before a definitive diagnosis of radial tunnel syndrome was made. Two unique anomalies were contributing factors in the radial nerve entrapment; one case demonstrated a completely tendinous proximal border of the extensor carpi radialis brevis and the other a bifid extensor carpi radialis brevis origin. Excellent pain relief, elimination of popping, and improvement of the paresthesias and paresis was achieved by release of the radial tunnel in cases unresponsive to conservative treatment.

Adult↗

Congenital hypoplastic thumb in the Silver syndrome--a case report and review of upper extremity anomalies in the world literature.

A case of classical Silver syndrome presented with a congenital hypoplastic thumb, absent thenar musculature, and partial index ankylosis. No previous association of congenital hypoplastic thumb and the Silver syndrome has been noted by Dr. Silver or described in the world literature. Restoration of thumb function was achieved in this particular case by the abductor digiti minimi transfer described by Huber. The upper extremity anomalies thus far reported with Silver syndrome in the world literature are summarized.

Child↗