Sterile abscesses in glioma patients treated by intraparenchymal injection of lymphokine-activated killer cells and recombinant interleukin-2: case reports

Earlier, we conducted Phase I clinical trials to determine any acute toxicity of adoptive immunotherapy with intralesional injections of autologous lymphocytes expressing lymphokine-activated killer (LAK) activity and recombinant interleukin-2 (rIL-2) in patients with malignant glioma. Within six weeks of craniotomy and intralesional injection of autologous LAK cells plus rIL-2, 3 of 29 patients demonstrated a decline in clinical status and evidence on computed tomographic and magnetic resonance imaging scans of edema and mass of unknown character at the site of previous surgery and immunotherapy. Craniotomy was performed to remove the tissue and reduce intracranial pressure. Microscopic examination of the excised material indicated no new tumor growth within the resected mass, but rather that the tissue had the histological characteristics of a chronic sterile abscess including necrosis, fibrosis, and influx of inflammatory cells. Factors that may have contributed to this reaction in the 3 patients were age, Karnofsky score, the extent of tumor excision, and immune status. All 3 had also been treated with greater than average numbers of rIL-2 activated lymphocytes that demonstrated significant in vitro LAK activity. The results suggest that in patients whose clinical status is good and who are not immunosuppressed by corticosteroids, the dose-limiting toxicity of intraparenchymal immunotherapy with LAK cells plus rIL-2 for glioma may be related to the total, absolute number of activated cells injected, and this toxicity develops over time and is manifested by development of a sterile abscess.     

Setaria cervi: Enzymes in microfilariae and in vitro action of antifilarials

Summary Microfilariae of bovine filarial parasiteSetaria cervi are equipped with the enzymes of glycolysis, pentose phosphate and PEP-succinate pathways and thus resemble the adult form in its metabolic pattern. Malate dehydrogenase was the most active enzyme in microfilariae followed by lactic dehydrogenase and fumarase, while phosphoglucoisomerase, PEP-carboxykinase and FDP-aldolase were comparatively less active. The very low ratio of PK/PEPCK inS. cervi microfilariae indicates active fixation of CO₂ into PEP to produce oxalacetate. Centperazine and diethylcarbamazine significantly inhibited PEP-carboxykinase, fumarate reductase and succinic dehydrogenase, suggesting that these antifilarials probably exert microfilaricidal action by blocking the PEP-succinate pathway.     

Hyaline globules and intracellular lumina in a hepatocellular carcinoma

The authors report ultrastructural findings on the morphogenesis of hyaline globular inclusions (HG) of a moderately well-differentiated hepatocellular carcinoma, with the features of a fibrolamellar variant. Pale blue cytoplasmic inclusions (pale bodies) of the tumor cells were shown to be intracellular lumina lined with numerous microvilli. Our findings suggest that HG were formed apparently by the successive deposition of fine granular materials in the lumina. Small accumulations were present in the intracellular lumina, which were seen on light microscopy as central hyaline cores of pale inclusions. Larger globular deposits, corresponding to HG and presumably mature ones, were lined closely with membranes devoid of microvilli that were probably shed intraluminally. Our observation was discussed with relation to the previous findings on the inclusions.     

Estimation of solid–liquid interfacial tension using curved surface of a soft solid

Unlike liquids, for crystalline solids the surface tension is known to be different from the surface energy. However, the same cannot be said conclusively for amorphous materials like soft cross-linked elastomers. To resolve this issue we have introduced here a direct method for measuring solid–liquid interfacial tension by using the curved surface of a solid. In essence, we have used the inner surface of tiny cylindrical channels embedded inside a soft elastomeric film for sensing the effect of the interfacial tension. When a liquid is inserted into the channel, because of wetting-induced alteration in interfacial tension, its thin wall deflects considerably; the deflection is measured with an optical profilometer and analyzed using the Föppl–von Kármán equation. We have used several liquids and cross-linked poly(dimethylsiloxane) as the solid to show that the estimated values of the solid–liquid interfacial tension matches with the corresponding solid–liquid interfacial energy reasonably well.Surface energy of a material is the energy required to create a unit area of new surface by the process of division, whereas surface tension is the isotropic surface stress associated with its deformation. For liquid, these two quantities are numerically equal because, when a liquid surface is deformed, the separation distances between molecules at the surface do not necessarily alter as molecules can move from the bulk to a deforming surface. It is generally not so for a solid, as it has been argued (1–3) that a solid surface consists of a constant number of atoms, so the work done to alter the separation distance between atoms at the surface is expected to depend on this distance itself. As a result, work of deformation is not necessarily the same as the thermodynamic work required to create a new surface. It is not clear, however, if this picture is true for all kinds of solids. For crystal surfaces the question is somewhat resolved as it has been shown both experimentally and theoretically (2, 4) that surface free energy is a function of area itself and therefore the surface tension is expected to be different from surface energy. However, for amorphous materials, like polymeric solids and cross-linked elastomers, the issue remains unresolved because, for these materials, the molecules can have local mobility which allows them to show liquid-like behavior, e.g., surface reconstruction in response to external cues (5, 6). It has not been possible, however, to state anything conclusively because for most solids surface tension has not been measured accurately. The difficulty arises because, when a solid deforms due to the application of external forces, the internal stresses at the bulk of it far exceed that at the surface (7), which prevents the estimation of surface tension. Even when the sole effect of surface tension is considered, for most solids it remains almost immeasurable as the deformation due to surface tension remains significantly small.In general, surface tension can deform only a sufficiently compliant solid, the extent of deformation of which can be estimated in terms of an elastocapillary length (8) defined as l = γ/μ, where γ and μ are, respectively, the surface tension and shear modulus of the solid. For a soft rubber-like elastomer, with γ = 22 mN/m and μ = 10⁶ Pa, the capillary length is estimated to be l = 22 nm, which is too small to be measured by standard techniques, e.g., optical microscopy. For example, it has been shown that surface tension can result in blunting of a sharp corner (radius of curvature → 0) of rubbery solid, thereby compromising the fidelity of pattern transfer (9), but it has not been possible to measure the surface tension because of very small deformation and the possibility of effect of surface tension being coupled with thermal and chemical stresses during cross-linking. However, when the modulus of the solid is diminished considerably, e.g., by over three orders of magnitude, μ ～ 10² ? 10³ Pa, the elastocapillarity leads to meso- to microscopic effects which become somewhat tractable by optical methods. Flattening of undulating surface of a soft gel (10), diminishing effect of adhesion-induced surface roughening of a confined gel layer (11), and prevention of creasing instability in compressed solid (12, 13) are signatures of surface tension of the solids, yet the deformation is too small, <1 μm, to allow accurate estimation of it.Apart from solid–air interfaces, solids in contact with a liquid also have been examined for interfacial tension-driven phenomena, e.g., formation of ridges at the three-phase contact line of a sessile liquid drop (14–18) placed on a compliant surface; stiffening of a soft gel embedded with tiny droplets of a liquid (19, 20); and compressive surface stress owing to Laplace pressure across a curved solid surface of a slender gel filament submerged inside a liquid and the resultant Rayleigh–Plateau instability (8, 21). Although deformation in all these experiments ranges from a few micrometers to hundreds of micrometers, they involve also measurement of liquid contact angle at the three-phase contact line which is generally hysteretic owing to metastable states in the energy landscape. Therefore, methods dependent on measurement of contact angle are expected to be colored by hysteresis and associated inaccuracies. Importantly, the above phenomena all occur in only very compliant solids (Young’s modulus ∼1 kPa) and therefore are not suitable for measurement of surface tension of stiffer solid (Young’s modulus ∼1 MPa).Recent experiments show that for such solids too, geometric amplification can result in significant deformation, thereby facilitating measurement of surface tension. For example, an incompressible elastic film, embedded with liquid-filled microstructures, bulges out considerably because of wetting (22, 23). The deflection of a flat, thin, circular elastomeric film of thickness t in contact with a liquid drop of radius c gets amplified by geometric ratio (24) (c/t): δ ～ (σ/μ)(c/t); here σ denotes the summation of bulk and surface stresses present in the film. This observation was used to extract a value of interfacial tension by extrapolating σ to vanishing thickness of the film. The estimated values obtained for interfacial tension were, however, much larger than the corresponding interfacial energies, which calls into question if the film was completely stress-free to begin with, as the base state was not characterized. Furthermore, large SD in data suggests also uncertainties in the measurement. In another elegant yet simple approach, surface tension was estimated by measuring deflection profile of a thin elastomeric film floating on a liquid (25) and indented by a pair of closely spaced cylinders. Here too, surface tension could be recovered in the limit of zero thickness of the film.The above discussions bring out the point that for amorphous solids the relation between solid surface tension and surface energy still remains unresolved. It is in this context that we present a direct and accurate method for measuring surface tension of a relatively stiffer solid, e.g., poly(dimethylsiloxane) (PDMS), the shear modulus of which is on the order of 1 MPa, i.e., at least three orders of magnitude larger than that used in various earlier experiments. In essence we have here a thin elastomeric layer embedded with monolithic tiny microchannels of circular cross-section such that the thickness of the elastomeric skin above the channel does not remain uniform but varies according to channel curvature. When a liquid fills in these channels, the thin skin bulges out or bulges in, following changes in solid–liquid interfacial tension. The extent of bulging deflection depends on the minimum thickness, t₀ of the skin and the diameter d of the channel. Thus, this experiment allows the effect of finite thickness of a solid layer to be coupled with its intrinsic curvature to attain significant deflection of the solid. We show also that the inherent symmetry of the geometry allows the problem to be analyzed in two dimension so that solid–liquid interfacial tension γ_sl can be directly estimated by analyzing the deflection profile of the skin. We have examined the efficacy of this method by estimating γ_sl for several liquids and PDMS system. For all these cases the numerical value of interfacial tension was found to be similar to the interfacial energy estimated from Young’s equation.     

Transverse cerebellar diameter: a reliable predictor of gestational age

ObjectivesTo determine accuracy of transverse cerebellar diameter (TCD) measurement in the prediction of gestational age (GA) in normal fetuses; to develop reference chart for TCD according to GA in Indian population.DesignA retrospective cross-sectional study.MethodUltrasonographic measurements in 300 singleton pregnant women included biparietal diameter (cm), head circumference (cm), abdominal circumference (cm), femur length (cm) and transverse cerebellar diameter (cm). Reference chart with mean TCD for corresponding gestational age (GA) in weeks was developed.ResultsStatistically significant relationship found between TCD and gestational age (R2=0.92, p=0.0006). Regression formulae based on TCD with other parameter can be used to predict gestational age of foetus. When TCD is compared with findings in other studies in different ethnic population, it is found that there is significant difference exists.ConclusionIn normally developing fetuses the TCD has linear correlation with advancing gestational age. A separate reference chart is required for every different population because ethnicity, nutrition and environmental factors can have impact on normal TCD values. This will help to avoid misinterpretation of data to determine gestational age.     

Multifocal electroretinogram in normal emmetropic subjects: correlation with optical coherence tomography

Aim of the Study:

To establish the normative database for multifocal electroretinogram (mfERG) parameters in a normal emmetropic population. To correlate the data so obtained with the central macular thickness obtained using the optical coherence tomography (OCT) scan.

Materials and Methods:

mfERG data were obtained from 222 eyes of 111 emmetropic subjects. The amplitude (nv/deg²) and implicit times (ms) of the first-order kernel mfERG responses (N1, P1, and N2 waves) were obtained and grouped into five rings (Ring 1: Central 2°, Ring 2: 2–5°, Ring 3: 5–10°, Ring 4: 10–15°, Ring 5: >15°). The central macular thickness (CMT) was obtained using the macular thickness scan protocol of the OCT.

Results:

The mfERG data obtained were used to create a normative database. The amplitudes of the mfERG waves were maximum in the fovea and progressively decreased with increasing eccentricity (P = 0.0001). The latencies of the P1 and N2 waves were longest in the central ring and progressively shortened with eccentricity (P = 0.0001). No statistically significant correlations were observed between central ring 1 parameters and the CMT.

Conclusion:

This study establishes normative database for mfERG parameters in an emmetropic population. No statistically significant correlation was noted between CMT and mfERG parameters.