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Biomedical subjects

J Kirk

Publications and source records attributed to J Kirk.

At least 145 records · Page 8Linked to original sources
PubMed1981

Novel tubular inclusions in the bone marrow in multiple sclerosis: an ultrastructural study of early autopsy material.

Samples of bone marrow taken at early autopsy from patients who died with multiple sclerosis and from control cases, were examined ultrastructurally with the aim of detecting any infectious agents which might be present. No recognizable virus or mycoplasma was detected. However, rare bizarre cellular inclusions were found in 2 cases. The inclusions which are unlike anything previously described in MS consisted of fine (ca 17 nm) sinuous tubules occasionally showing dilated discoid ends. They occurred together with fragmentary electron opaque material in large membrane bound vacuoles in unidentified cells. Despite superficial resemblance to some viral nucleocapsids it is considered more likely that they have been formed as a result of degenerative phagocytic or autolytic activity. The specificity or otherwise of these inclusions to MS remains to be demonstrated.

Bone Marrow↗
PubMed1980

Environmental dermatitis: changing patterns.

Patch tests in 1000 cases of contact allergic dermatitis observed between 1972 and 1978 are recorded in detail, and compared in general with patch tests in a previously recorded 1000 cases of contact allergic dermatitis between 1964 adn 1972. The routine use, since 1974, of patch tests as advised by the International Contact Dermatitis Research Group has increased the detection of dermatitis caused by nickel, paraphenylene-diamine and related dyes, formaldehyde and perfumes (balsam of Peru), which indicates that aimed patch tests alone may be inadequate. The number of cases of dermatitis caused by antifungal agents and topical antihistamines decreased after Commonwealth and State legislation prohibiting their use was passed.

Allergens↗
PubMed1980

An investigation of the alternating fractionation formula of the Cumulative Radiation Effect.

The alternating fractionation formula of the Cumulative Radiation Effect (CRE) system was investigated using the mouse intestinal crypt system as a method of assessment of the amount of radiation damage in a normal tissue. The experimental results revealed that the formula is correct in predicting an increased effect with alternating large and small sized fractions, when compared with a standard schedule where the fraction size was kept constant but achieved the same total dose. However, the results also demonstrated that the order in which the alternate fractions were administered affected the amount of radiation damage produced in the tissue. This observation is in contradiction to another prediction of the formula, that the order in which equal numbers of fractions of different magnitudes are administered, will have no effect on the biological end point. The formula, therefore, is only an approximate model of radiation damage in normal tissue and much more information is required before it can be improved upon.

Animals↗
PubMed1979

Pseudoviral hollow-cored vesicles in multiple sclerosis brain.

Novel, superficially 'virus-like' hollow-cored particles 50--60 nm in diameter were found in the perivascular extracellular space of the brain from a patient who died with acute multiple sclerosis (MS). It is concluded that they are not virions but are derived from myelin undergoing vesicular demyelination. This case demonstrates the need for caution in the interpretation of unusual electron microscopic appearances.

Acute Disease↗
PubMed1979

Investigation of time-gap formulae on the CRE system using mouse tissue as a biological model.

The cumulative radiation effect (CRE) is one of several empirical scalar descriptions of biological effect which enable corrections to be made for gaps in radiotherapy treatment. Predictions of this theory were tested using mouse crypt regeneration and mouse skin as biological models. These experimental results are discussed in terms of the dependence of tissue regeneration potential during a gap on the biological effect achieved before the gap, and on gap length. A hypothesis is proposed to reconcile the apparent conflict between the two experiments. While the simple exponential gap formulation of the CRE is seen to be inadequate, insufficient data are available at present to modify it.

Animals↗
PubMed1979

The fine structure of the cns in multiple sclerosis. II. Vesilcular demyelination in an acute case.

Tubular vesicular and net-like dissolution of myelin sheaths associated with complete demyelination and preservation of axons, is described in the brain, obtained within 4 h of death, from a patient who died with acute multiple sclerosis (MS). It was rare, being found in only three out of twenty-three blocks examined, and was seen mainly in the partially demyelinated margin of an active plaque in the white matter. The possibility that post-mortem autolytic changes or fixation artefact might have accounted for the appearances is considered, but is thought unlikely. The findings, though not specific would be expected if current theories invoking myelin-directed 'autoimmune' mechanisms in MS pathogenesis are correct. However, other myelin-directed mechanisms cannot be excluded on the basis of this evidence alone.

Acute Disease↗
PubMed1979

Systemic lupus erythematosus clinically resembling multiple sclerosis and with unusual pathological and ultrastructural features.

A case of systemic lupus erythematosus is described which clinically resembled multiple sclerosis and in which the lesions were restricted to the central nervous system. The necropsy findings of vascular thickening and necrosis in the spinal cord and in a posterior nerve root explain the main clinical abnormalities. Clinical signs of the terminal peritonitis secondary to cholecystitis were absent or minimised probably because of the steroid therapy and spinal cord necrosis. Primary demyelination was not demonstrated though electronmicroscopy revealed lattice fibrillar inclusions within a few myelin sheaths. An unusual ultrastructural feature was the finding of "rod-shaped tubular bodies" in large numbers in the endothelial cells of cerebral blood vessels. The incidence and morphology of these organelles are compared with those of the intracisternal tubuloreticular structures (TRS) commonly found in systemic lupus erythematosus.

Aged↗
PubMed1978

Acne treated with a tropical tetracycline preparation: results of a one-year multi-group study.

One hundred five patients were treated effectively with topically applied tetracycline in an ethanol-water solution with n-decyl methyl sulfoxide, and observed for a year. Comedones and cystic lesions were least responsive to topical tetracycline. Side effects, which were minor, included yellow staining of facial skin and stinging after application. Two patients, one with juvenile diabetes and one with congenital nephritis, successfully used the preparation without adverse effects.

Acne Vulgaris↗
PubMed1978

Effects of processing milk on concentrations of glucocorticoids in milk.

Concentrations of glucocorticoids were measured by protein binding in milk subjected to various processing methods. Raw whole milk was collected once per week for 3 wk from bulk milk tanks of each of 10 farms. Nine combinations of processing were tested: 1) none, 2) high-temperature short-time pasteurization of whole milk, 3) high-temperature short-time pasteurization and homogenization of whole milk, 4) bulk pasteurization of whole milk, 5) bulk pasteurization and homogenization of whole milk, 6) high-temperature short-time pasteurization of skim milk, 7) high-temperature short-time pasteurization and homogenization of skim milk, 8) bulk pasteurization of skim milk, and 9) bulk pasteurization and homogenization of skim milk. Mean concentrations of total glucocorticoids ranged from .46 to .65 ng/ml and were not different among either processing methods or whole versus skim milk classifications. No correlations were positive between percentage of fat and concentration of glucocorticoids in whole milk (-.22) or skim milk(-.09).

Animals↗
PubMed1977

Cumulative radiation effect. Part VI: simple nomographic and tabular methods for the solution of practical problems.

In five previous papers, the concept of the Cumulative Radiation Effect (CRE) has been presented as a scale of accumulative sub-tolerance radiation damage. The biological effect generated in normal connective tissue by fractionated or continuous radiation therapy given in any temporal arrangement is described by the CRE on a unified scale of assessment, so that a unique value of the CRE describes a specific level of radiation effect. The basic methods of evaluating CREs were shown in these papers to facilitate a full understanding of the fundamental aspects of the CRE-system, but these methods can be time-consuming and tediuous for complex situations. In this paper, simple nomographic and tabular methods for the solution of practical problems are presented. An essential feature of solving a CRE problem is firstly to present it in a concise and readily appreciated form, and, to do this, nomenclature is introduced to describe schedules and regimes as compactly as possible. Simple algebraic equations are derived to describe the CRE achieved by multi-schedule regimes. In these equations, the equivalence conditions existing at the junctions between schedules are not explicit and the equations are based on the CREs of the constituent schedules assessed individually without reference to their context in the regime as a whole. This independent evaluations of CREs for each schedule results in a considerable simplification in the calculation of complex problems. The calculations are further simplified by the use of suitable tables and nomograms, so that the mathematics involved is reduced to simple arithmetical operations which require at the most the use of a slide rule but can be done by hand. The order of procedure in the presentation and calculation of CRE problems can be summarised in an evaluation procedure sheet. The resulting simple methods for solving practical problems of any complexity on the CRE-system are demonstrated by a number of examples.

Connective Tissue↗