Biomedical subjects
Publications and source records attributed to D Lim.
Microprobe analysis was performed at the cellular and subcellular levels of type I and type II vestibular hair cells. In principle the same types of elemental histograms were found in the two types of hair cells studied. High concentrations of Cl and K were detected in stereocilia, whereas calcium was found when analyzing stereocilia and the supranuclear cytoplasm.
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The incidence of oncofoetal antigens has been reported to be increased in patients with gynaecological cancers. In this study the incidence of CEA, AFP, and hCG (beta subunit) were studied in patients with adenocarcinoma of the ovary, adenocarcinoma of the cervix, and squamous-cell carcinoma of the cervix. Using a low cut-off point (CEA 2.5 microgram/l, AFP 5 microgram/l, and hCG 3 i.u./l) there is an unacceptably high proportion of control patients having one or more positive tests (42-54%) compared to cancer-bearing patients (67%). The specificity of the tests can be increased to over 95% by increasing the cut-off point to CEA 10 microgram/l, AFP 10 microgram/l, and hCG 10 i.u./l). Although this reduces the sensitivity considerably, the incidence of false positives in the control population is reduced to nil in non-cancer patients and to 2% in cancer patients tested when free of tumour, compared to 17% of patients with cancer of the ovary, 33% with adenocarcinoma of the cervix, and 6% with squamous-cell carcinoma of the cervix. Patients with adenocarcinoma of the cervix were clearly distinguishable from those with squamous-cell carcinoma of the cervix by these tests. There was also a significant correlation between AFP and hCG levels in adenocarcinoma of the cervix (r = 0.53, P less than 0.05).
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Secretory component of IgA (SIgA) was isolated by DEAE Sephacel anion exchange chromatography and Sephadex G200, radioiodinated, and a radioimmunoassay procedure developed. The standard inhibition curve was linear to 10 ng/ml. The levels of SIgA in the serum of normal persons was 1.9 +/- 0.1 microgram/ml (mean +/- SE), whereas in lactating women the level was 5.5 +/- 0.5. In cancer of the ovary, endometrium, and cervix, the levels of SIgA were 3.1 +/- 0.3, 2.2 +/- 0.5, and 2.8 +/- 0.4 microgram/ml respectively. A significantly increased level of SIgA was found in 13/24 (54%) of patients with cancer of the ovary and in 5/15 (33%) of patients with cancer of the cervix. Further studies are in progress to establish levels of SIgA following surgery and chemotherapy.
A previously healthy 6-year-old boy who presented with meningococcal meningitis responded favorably to ampicillin, but suffered two and possibly three repeat attacks in the ensuing month. No abnormality of the otolarynx, skin, or neuroskeleton was found. The infecting strain, Neisseria meningitidis, Group Y, Type IV, was sensitive to the therapeutic agents used, and antibiotic levels were adequate. Serum bactericidal antibody titers against autologous meningococci were high. Serum complement hemolytic bactericidal activities, however, were entirely lacking, and this was attributable to a complete deficiency of C6. Measurements of the remaining complement components, C-dependent chemotaxis and opsonization, neutrophil function, specific immunity, and the coagulation system, were normal. The parents had half-normal C6 levels. Recurrence of meningitis in this patient supports the concept that complement plays a role in resistance to certain microorganisms and emphasizes the need for complete evaluation of the complement system in individuals with unexplained repeated infections.
From two families, one with Clr deficiency and the other with C6 deficiency, evidence was obtained suggesting genetic independence between the transmission of a 50% deficit in the functional activity of these two complement components and the inheritance of the HL--A system, the ABO system, and the sex of individuals.
Human external auditory canal skin, with a special emphasis on the secretory system, was studied by light, transmission electron and scanning electron microscopy. Two types of secretory glands were observed: modified apocrine (ceruminous) and sebaceous. The sebaceous secretory cellere homogeneous; on the other hand, modified apocrine secretory cells contained heterogeneous secretory granules. They were ither dark granules or light granules. Evidence to support both the apocrine as well as the eccrine mode of secretion was noted in the modified apocrine gland. This finding is partly in agreement with early reports based on light microscopy with suggested only an apocrine mode and data based on transmission electron microscopy which showed only the eccrine mode. Significance of the secretion by the external ear canal and its role in a local immune defense system is discussed.
The human middle ear corpuscles originally described by von Troeltsch are examined by means of light microscopy in 124 subjects, and electron microscopy in 27 subjects. While the corpuscles are not observed in all 19 individuals under age six, and in all 20 adults who had a history of suppurative otitis media, an average of six corpuscles per temporal bone is found in 98 percent of 83 adult subjects who had no history of middle ear disease. Two-thirds of the corpuscles are located in the mastoid, and the remainder in the middle ear. Often, they become bifurcated or trifurcated. Although light microscopy shows that the corpuscle is formed by lamellar capsules and a central core resembling pacinian corpuscles, electron microscopic study failed to confirm that this structure is a typical pacinian corpuscle. Subsequently, possible physiological significance of this corpuscle is discussed.
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Immunological phenomena occurring in the mucosa of the middle ear and Eustachian tube were investigated following tubal obstruction in squirrel monkeys which produced middle ear effusions. Although there are many variations among specimens, in general all classes of immunoglobulin producing plasma cells have shown an increase in number and/or an increase in intensity of fluorescence. IgG and IgA-producing plasma cells were more prominent than those producing other immunoglobulins. These findings support the concept that the middle ear and Eustachian tube in monkeys as in humans is protected by an immunodefense system.
Localization of elements at the cellular and sub-cellular levels was performed with the energy dispersive X-ray microanalysis technique, using shock-frozen, freeze-dried and araldite-embedded mouse (CBA/CBA) cochleae sectioned dry. Anatomical identification occurred in the STEM (scanning transmission electron microscopy) mode. In inner hair cell stereocilia the K/Na ratio was 70:1 but only 20:1 in the cytoplasm. In outer hair cell cytoplasm the K/Na ratio was 11:1 while the ratio in stereocilia was similar to that in inner hair cells. Ca was identified in stereocilia and the upper part of the cytoplasm of both outer and inner hair cells. The elemental composition in the subtectorial space is endolymph-like and that in the inner tunnel of the organ of Corti is similar to extracellular fluid. Considerable regional differences in elemental composition occur in the tectorial membrane with regard to P, K and Ca. The highest concentration of Ca occurs in the basal part of the tectorial membrane towards the sensory hairs. The highest concentration of K occurs in the basal and outer parts whereas the middle part of the tectorial membrane contains low levels of both K and Ca. The elemental composition changes in two main directions: 1) from the limbal (growing) region to the tip of the tectorial membrane, and, 2) from upper to lower surfaces. The three cell types of the stria vascularis differ considerably in elemental composition. The highest concentration of K occurs in marginal cells. The basal cells contain more K than do the intermediate cells. A significantly higher concentration of Ca, Cl and Na occurs in marginal cell cytoplasm than in any other cell type in the stria vascularis.
This study demonstrates the mechanism of sensory hair fusion and its relationship to glycocalyx on the hair cells in the vestibular epithelia of gentamicin-treated guinea pigs, using a ruthenium red staining technique. 0.1 ml of a solution containing 50 mg gentamicin sulphate per 1 ml was injected once into the middle ear. After 7 days, various stages of sensory hair degeneration were observed. The glycocalyx was clearly visualized by ruthenium red. The gentamicin-induced hair damage started with a local decrease in or loss of glycocalyx from neighbouring sensory hairs, followed by formation of local attachment areas of membrane sensory hairs. These findings suggest that the glycocalyx of the sensory cell may play an important role in separating the cilia as well as maintaining the organization of the bundle. Therefore, the decrease in or loss of glycocalyx from the hair bundle of sensory cells affected by gentamicin, either directly or secondarily, can be considered as closely related to the fusion of the sensory hairs.
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