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In-plane InGaAs/Ga(As)Sb heterojunction tunnel diodes are fabricated by selective area molecular beam epitaxy with two different architectures: either radial InGaAs core/Ga(As)Sb shell nanowires or axial InGaAs/GaSb heterojunctions. In the former case, we unveil the impact of strain relaxation and alloy composition fluctuations at the nanoscale on the tunneling properties of the diodes, whereas in the latter case we demonstrate that template assisted molecular beam epitaxy can be used to achieve a very precise control of tunnel diodes dimensions at the nanoscale with a scalable process. In both cases, negative differential resistances with large peak current densities are achieved.

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During chronic tonsillitis, the relationship between proliferation and apoptosis of lymphocytes in tonsillar follicles can be disturbed, which gives rise to attenuation of tonsil immunocompetence and diminishing its contribution in systemic immunity. In this study, we have quantified the cells expressing the markers of proliferation and apoptosis in the follicles of the palatine tonsil. Six tonsils from patients aged 10-29 years with hypertrophic tonsillitis and five tonsils from patients aged 18-22 years with recurrent tonsillitis were studied. The sections of paraffin blocks of tonsillar tissue were stained by the immunohistochemical LSAB/HRP method with the utilisation of antibodies for: Ki-67 antigen-cell marker of proliferation; Bcl-2 and survivin anti-apoptotic factors and Fas/CD95, caspase-3 and Bax pro-apoptotic factors. The size of lymphoid follicles, i.e. mean follicle area and number of lymphoid follicle immunopositive cells per mm2 of a slice area, i.e. numerical areal density were determined by the quantitative image analysis. The localisation of Ki-67, Bcl-2, survivin, Fas/CD95, caspase-3 and Bax- immunopositive cells inside the palatine tonsil was similar in both types of tonsillitis. The number of Ki-67 immunopositive cells was significantly (p < 0.01) larger in the tonsils with hypertrophic tonsillitis (14681.4 ± 1460.5) in comparison to those with recurrent tonsillitis (12491.4 ± 2321.6), although the number of survivin and caspase-3 immunopositive cells was significantly (p < 0.05) larger in recurrent tonsillitis (survivin, 406.9 ± 98.4; caspase-3, 350.4 ± 119.4) when compared to those with hypertrophic tonsillitis (survivin, 117.4 ± 14.5; caspase-3, 210 ± 24). Our results show that the rate of the proliferation and apoptosis of follicular lymphocytes is different in various types of tonsillitis. This suggests that the immunological potential of the palatine tonsil varies in patients with hypertrophic and recurrent tonsillitis, which in practice poses a dilemma over the choice of conservative or surgical treatment.

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BACKGROUND: Palatine tonsils represent the first place of contact for a variety of antigenic substances present in air and food. Upon antigen stimulation, the interactions between T and B lymphocytes in the tonsil are known to depend on the expression of different co-stimulatory molecules, including proteolytic ectoenzymes. Dipeptidyl peptidase IV (DPP IV) and aminopeptidase N (APN), as T lymphocyte co-stimulatory molecules, participate in the regulation of the immune response during inflammation. METHODS: In this study, the serum and lymphocyte enzymatic activity of DPP IV and APN was investigated in 32 patients, 13 with recurrent tonsillitis (RT) and 19 with tonsillar hypertrophy (TH), before and one month after tonsillectomy. The enzymatic activity of DPP IV and APN in tonsillar lymphocytes and serum was determined kinetically at 37 degrees C using Gly-Pro-p-nitroanilide (for DPP IV) and Ala-p-nitroanilide (for APN) as chromogenic substrates. RESULTS: Significantly higher serum DPP IV and APN activities (P<0.001) were found in TH patients compared with those with RT before tonsillectomy. DPP IV activity in TH patients was also elevated compared with the control of the same age (P<0.001), whereas the activity of APN was the same as the control group. The activity of both enzymes was the same as of controls after tonsillectomy. In addition, the results show that DPP IV and APN activities in serum decrease significantly with age. Tonsillar lymphocytes demonstrated a wide range of DPP IV and APN activities without significant differences between the investigated groups. CONCLUSION: An increased serum DPP IV activity was observed in TH patients compared with both RT patients and controls before tonsillectomy. After tonsillectomy, all activities were similar. The results suggest that serum DPP IV activity may have potential as a diagnostic marker for patients with TH.

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The nephroprotective effects of pentoxifylline, a methylxantine, were studied in glycerol-induced acute renal failure. Glycerol treated rats exhibited collecting duct and medullary ascending limb dilation and casts, with focal tubular damage, confined mainly to the superficial cortex. In the interstitium focal mononuclear infiltration was observed. In some glomeruli there was swelling of mesangial spaces and mesangial cells. Pentoxifylline injected to glycerol pretreated rats exerted a protective effect. Only few groups of proximal tubules in the subcapsulary region of renal cortex showed necrosis and tubulorhexis. There were not leukocyte infiltrations or vascular congestion. Morphometric analysis showed increased surface area fraction of tubular lumen in rats treated with glycerol (p < 0.01) compared to those in controls. Intratubular cast formations in rats treated with glycerol alone were significantly higher than in rats given pentoxifylline in addition to glycerol. Kidney cortex ectopeptidases (APA, APN and DPP IV) were not significantly changed after glycerol administration. Serum creatinine and blood urea were markedly increased in glycerol treated rats, however, pentoxifylline reduced significantly their levels. This study in glycerol-induced acute renal failure showed a marked renal morphologic and functional protection by pentoxifylline.

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Renal ischemia as well as oxygen metabolites play an important role in renal injury during myoglobinuric acute renal failure (ARF). On the other hand, flavonoids, a diverse group of constituents naturally occurring in plants, have a strong antioxidative activity, and have been implicated in vascular relaxation. In this study the protective effect of a new bioflavonoid proanthocyanidin-BP1 (BP1), extracted from seeds of grapes, was evaluated in glycerol-induced ARF in rats. Stereological methods were used to quantify changes in renal morphology associated with ARF. Volume density of tubular lumen and intratubular cast formations, nuclear parameters (area, diameter, volume) of epithelial cells in the cortical proximal tubules, and glomerular parameters (surface area, diameter, volume, perimeter) were estimated on kidney sections of rats treated either with 50% glycerol (8 mL/kg i.m.) alone. BP1 (20 mg/kg i.p.) in addition to glycerol, or BP1 alone. It was noted that the volume density of tubular lumen and cast formations were significantly lower (p < 0.001) in kidneys of the rats treated with BP1 in addition to glycerol, compared with those treated with glycerol alone. There were no significant differences in glomerular and nuclear parameters between glycerol treated, and BP1 in addition to glycerol treated rats. Renal function was significantly improved in rats treated with BP1 in addition to glycerol. The results suggest that BP1 is a protective agent in glycerol model of ARF. This effect is probably due to the antioxidative activity of BP1 and reduced toxicity of myoglobin in renal tissue. Moreover, it is possible that the ability of BP1 to protect the kidney is dependent upon renal vascular relaxation. The potential beneficial effects of bioflavonoid-BP1 demonstrated in experimental ARF could be considered in therapy of myoglobinuric ARF.

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The histochemical localisation of two ecto-enzymes, 5'-nucleotidase (5'-NT) and Mg(2+)-ATPase, was investigated in hyperplastic and recurrent tonsillitis. Detection of enzymes was performed on frozen sections using the classical lead nitrate method. Activity of 5'-NT was demonstrated particularly in the cells of lymphoid follicles and in the basal layer of the surface tonsillar epithelium. There was no difference in localisation of 5'-NT between hyperplastic and recurrent tonsillitis, whereas a stronger reaction in follicular mantle zones was observed in recurrent tonsillitis compared to hyperplastic tonsillitis. Mg(2+)-ATPase activity was mainly associated with the cells lining the tonsillar crypt, with the interfollicular areas and blood vessels. In recurrent tonsillitis only half of the studied follicular germinal centres expressed Mg(2+)-ATPase activity, compared to hyperplastic tonsillitis. The similar localisation of 5'-NT and ecto-ATPase in both types of chronic tonsillitis suggests that in inflamed tonsils expression of investigated enzymes probably does not depend on the type of chronic tonsillitis.

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The activities of two ectoenzymes,Mg(2+)-ATPase (ATPase) and 5'-nucleotidase (5'-NT) from tonsillar mononuclear cells (TMC) and peripheral blood mononuclear cells (PBMC) were investigated in idiopathic tonsillar hyperplasia and recurrent tonsillitis. The ATPase activity of TMC was significantly higher in recurrent tonsillitis than in idiopathic tonsillar hyperplasia, whereas no difference was demonstrated in ATPase activity of PBMC. The activity of 5'-NT was similar in both investigated groups. However, ATPase and 5'-NT activities were significantly higher in TMC compared to PBMC. Such results suggest a possible role of ATPase in the activation of TMC during the course of chronic tonsillitis and indicate a difference in the function of TMC and PBMC.

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