Skin and hair follicle integrity is crucially dependent on beta 1 integrin expression on keratinocytes

beta 1 integrins are ubiquitously expressed receptors that mediate cell-cell and cell-extracellular matrix interactions. To analyze the function of beta1 integrin in skin we generated mice with a keratinocyte-restricted deletion of the beta 1 integrin gene using the cre-loxP system. Mutant mice developed severe hair loss due to a reduced proliferation of hair matrix cells and severe hair follicle abnormalities. Eventually, the malformed hair follicles were removed by infiltrating macrophages. The epidermis of the back skin became hyperthickened, the basal keratinocytes showed reduced expression of alpha 6 beta 4 integrin, and the number of hemidesmosomes decreased. Basement membrane components were atypically deposited and, at least in the case of laminin-5, improperly processed, leading to disruption of the basement membrane and blister formation at the dermal-epidermal junction. In contrast, the integrity of the basement membrane surrounding the beta 1-deficient hair follicle was not affected. Finally, the dermis became fibrotic. These results demonstrate an important role of beta 1 integrins in hair follicle morphogenesis, in the processing of basement membrane components, in the maintenance of some, but not all basement membranes, in keratinocyte differentiation and proliferation, and in the formation and/or maintenance of hemidesmosomes.

Hypertonic saline-dextran improves intestinal perfusion and survival in porcine endotoxin shock

OBJECTIVE

To examine the effects of hypertonic (7.5%) saline-6% dextran 70 (HSD) and isotonic (0.9%) saline-6% dextran 70 (ISD) on cardiovascular function and intestinal perfusion in experimental endotoxin shock.

DESIGN

Experimental, randomized, unblinded, interventional study.

SETTING

University experimental animal laboratory.

SUBJECTS

Anesthetized and mechanically ventilated landrace pigs (n = 24).

INTERVENTIONS

Induction of endotoxin (ET) shock by infusion of Escherichia coil lipopolysaccharide endotoxin (serotype 0111: B4) followed by no fluid treatment (control; C) or small-volume (4 mL/kg) treatment with HSD or ISD.

MEASUREMENTS AND MAIN RESULTS

Mean arterial pressure, central venous pressure, pulmonary artery pressure, pulmonary artery occlusion pressure, cardiac output, portal vein blood flow, intestinal microcirculation, intramucosal (regional) P(CO2), intestinal-arterial gap of CO2, and intramucosal pH were monitored, and blood gases were analyzed. Infusion of ET resulted in hypokinetic shock, which in untreated animals led to cardiovascular deterioration and a survival rate of only 33% at 300 mins after start of ET infusion. ISD treatment transiently improved hemodynamic variables and mucosal blood flow but did not affect the survival rate vs. C. Significant beneficial, long-lasting effects of HSD infusion on hemodynamics, especially on mucosal blood flow and intramucosal pH, were demonstrable, resulting in a survival rate of 86%. The relative risk of death at 300 mins was 1.20 for ISD vs. C and 0.17 for HSD vs. C.

CONCLUSION

Small-volume HSD resuscitation is much more effective than ISD resuscitation. Variables that were improved include cardiac output, portal blood flow, and intestinal mucosal blood flow in ET shock, all of which improve survival. Such beneficial effects of HSD on splanchnic perfusion may be of value in treating critically ill septic patients in the intensive care unit.

Conversion of alpha-lactalbumin to a protein inducing apoptosis

In this study alpha-lactalbumin was converted from the regular, native state to a folding variant with altered biological function. The folding variant was shown to induce apoptosis in tumor cells and immature cells, but healthy cells were resistant to this effect. Conversion to HAMLET (human alpha-lactalbumin made lethal to tumor cells) required partial unfolding of the protein and a specific fatty acid, C18:1, as a necessary cofactor. Conversion was achieved with alpha-lactalbumin derived from human milk whey and with recombinant protein expressed in Escherichia coli. We thus have identified the folding change and the fatty acid as two key elements that define HAMLET, the apoptosis-inducing functional state of alpha-lactalbumin. Although the environment in the mammary gland favors the native conformation of alpha-lactalbumin that serves as a specifier in the lactose synthase complex, the conditions under which HAMLET was formed resemble those in the stomach of the nursing child. Low pH is known to release Ca(2+) from the high-affinity Ca(2+)-binding site and to activate lipases that hydrolyze free fatty acids from milk triglycerides. We propose that this single amino acid polypeptide chain may perform vastly different biological functions depending on its folding state and the in vivo environment. It may be speculated that molecules like HAMLET can aid in lowering the incidence of cancer in breast-fed children by purging of tumor cells from the gut of the neonate.

Salmonella infection of bone marrow-derived macrophages and dendritic cells: influence on antigen presentation and initiating an immune response

Traditionally macrophages (MPhi) have been considered to be the key type of antigen presenting cells (APC) to combat bacterial infections by phagocytosing and destroying bacteria and presenting bacteria-derived antigens to T cells. However, data in recent years have demonstrated that dendritic cells (DC), at their immature stage of differentiation, are capable of phagocytosing particulate antigens including bacteria. Thus, DC may also be important APC for initiating an immune response to bacterial infections. Our studies focus on studying how DC and MPhi process antigens derived from bacteria with no known mechanism of phagosomal escape (i.e. Salmonella typhimurium) for T cell stimulation as well as what role these APC types have in Salmonella infection in vivo. Using an in vitro antigen processing and presentation assay with bone marrow-derived (BM) APC showed that, in addition to peritoneal elicited MPhi and BMMPhi, BMDC can phagocytose and process Escherichia coli and S. typhimurium for peptide presentation on major histocompatibility complex (MHC) class I (MHC-I) and class II MHC-II. These studies showed that both elicited peritoneal MPhi and BMMPhi use an alternate MHC-I presentation pathway that does not require the transporter associated with antigen processing (TAP) or the proteasome and involves peptide loading onto a preformed pool of post-Golgi MHC-I molecules. In contrast, DC process E. coli and S. typhimurium for peptide presentation on MHC-I using the cytosolic MHC-I presentation pathway that requires TAP, the proteasome and uses newly synthesized MHC-I molecules. We further investigated the interaction of Salmonella with BMDC and BMMPhi by analyzing surface molecule expression and cytokine secretion following S. typhimurium infection of BMDC and BMMPhi. These data reveal that Salmonella co-incubation with BMDC as well as BMMPhi results in upregulation of MHC-I and MHC-II as well as several co-stimulatory molecules including CD80 and CD86. Salmonella infection of BMDC or BMMPhi also results in secretion of cytokines including IL-6 and IL-12. Finally, injecting mice with BMDC that have been loaded in vitro with S. typhimurium primes naïve CD4(+) and CD8(+) T cells to Salmonella-encoded antigens. Taken together, our data suggest that DC may be an important type of APC that contributes to the immune response to Salmonella.

Specific angiotensin II receptor blockage improves intestinal perfusion during graded hypovolemia in pigs

OBJECTIVE

To investigate the potential of specific angiotensin II subtype 1 (AT1) receptor blockade to modify the mesenteric hemodynamic response to acute hypovolemia and retransfusion.

DESIGN

Prospective, randomized, controlled experimental study.

SETTING

University-affiliated animal research laboratory.

SUBJECTS

Fasted, anesthetized, ventilated, juvenile domestic pigs of both sexes.

INTERVENTIONS

Acute, graded hypovolemia by 20% and 40% of the total estimated blood volume followed by retransfusion in control animals (CTRL; n = 10) and animals pretreated with the AT1 receptor blocker candesartan (CAND; n = 10).

MEASUREMENTS AND MAIN RESULTS

Invasive monitoring of arterial and central venous blood pressures, cardiac output, portal venous blood flow, and jejunal mucosal blood flow. Blood gases were repeatedly analyzed to calculate oxygen delivery and consumption. Thirty minutes after each level of hypovolemia at 20% and 40%, cardiac output was decreased in CTRL animals from a baseline of 2.9 +/- 0.1 to 1.8 +/- 0.2 and 1.1 +/- 0.2 L/min, with no differences compared with CAND animals. Cardiac output was restored to 3.0 +/- 0.3 L/min 30 mins after retransfusion in CTRL animals, with no significant intergroup differences. Baseline portal venous blood flow (Q(MES)) and jejunal mucosal perfusion (PU(JEJ)) were greater in CAND animals compared with CTRL animals. During graded hypovolemia, CAND animals maintained Q(MES) and PU(JEJ) at significantly higher levels compared with CTRL animals, particularly after 40% hemorrhage (+221% and + 244%, respectively, relative to the mean values in CTRL animals). The same pattern was observed after retransfusion. Moreover, the calculated mesenteric critical oxygen delivery was significantly greater in CTRL animals (74 mL/min) compared with CAND animals (34 mL/min). No animals died in the CAND group, whereas four animals died during 40% hypovolemia or retransfusion in the CTRL group.

CONCLUSIONS

Specific AT1 blockade before acute hypovolemia significantly ameliorated mesenteric and, in particular, jejunal mucosal hypoperfusion. In addition, cardiovascular stability was improved, and mortality in conjunction with acute hypovolemia and retransfusion could be completely avoided. These findings support a fundamental role of the renin-angiotensin system in the mesenteric response to acute hypovolemia and indicate a substantial interventional potential for candesartan in conjunction with circulatory stress.

A folding variant of alpha-lactalbumin with bactericidal activity against Streptococcus pneumoniae

This study describes an alpha-lactalbumin folding variant from human milk with bactericidal activity against antibiotic-resistant and -susceptible strains of Streptococcus pneumoniae. The active complex precipitated with the casein fraction at pH 4.6 and was purified from casein by a combination of anion exchange and gel chromatography. Unlike other casein components, the active complex was retained on the ion-exchange matrix and eluted only with high salt. The eluted fraction showed N-terminal and mass spectrometric identity with human milk alpha-lactalbumin, but native alpha-lactalbumin had no bactericidal effect. Spectroscopic analysis demonstrated that the active form of the molecule was in a different folding state, with secondary structure identical to alpha-lactalbumin from human milk whey, but fluctuating tertiary structure. Native alpha-lactalbumin could be converted to the active bactericidal form by ion-exchange chromatography in the presence of a cofactor from human milk casein, characterized as a C18:1 fatty acid. Analysis of the antibacterial spectrum showed selectivity for streptococci; Gram-negative and other Gram-positive bacteria were resistant. The folding variant of alpha-lactalbumin is a new example of naturally occurring molecules with antimicrobial activity.

Evaluation of the BioRID P3 and the Hybrid III in pendulum impacts to the back--a comparison to human subject test data

The BioRID P3 (Biofidelic Rear Impact Dummy) and the Hybrid III were evaluated in pendulum impacts to the back and compared to data from previous cadaver tests. The test setup impacting seated cadavers was reproduced with a pendulum impacting seated dummies at the level of T6 (6th thoracic vertebra). The pendulum mass was 23 kg and the impact velocity 4.6 m/s. The results showed that the BioRID P3 was more biofidelic than the Hybrid III in terms of the peak responses and the temporal window of the head and head relative to T1 horizontal, vertical, and angular displacement. This study is an evaluation of both the BioRID P3 and the Hybrid III against a recently available set of human subject data. The study meets the need for validation of the BioRID P3 at a higher impact severity than has been previously accomplished.

Intestinal perfusion during pneumoperitoneum with carbon dioxide, nitrogen, and nitric oxide during laparoscopic surgery

OBJECTIVE

To find out what effect insufflation pressure and type of gas have on intestinal perfusion during pneumoperitoneum.

DESIGN

Randomized, controlled, prospective, experimental study.

SETTING

University affiliated animal experimental laboratory, Sweden.

ANIMALS

Fasted, anaesthetised, domestic pigs of both sexes operated on laparoscopically (n = 7, weight 26-31 kg).

INTERVENTIONS

Insufflation of carbon dioxide (CO2), nitric oxide (NO), or nitrogen (N2) at intra-abdominal pressures of 0, 5, 10, 15 and 20 mm Hg.

MAIN OUTCOME MEASURES

Cardiac output, portal blood flow, and jejunal mucosal perfusion.

RESULTS

Cardiac output decreased during N2 and NO (15, 20 mm Hg) but not during CO2 insufflation because of an accompanying tachycardia. Portal flow decreased during insufflation with N2 and NO (15, 20 mm Hg) and CO2 (20 mm Hg). Jejunal perfusion was reduced during N2 and NO insufflation (5-20 mm Hg) but remained unchanged during CO2 insufflation (5-20 mm Hg).

CONCLUSIONS

Insufflation with CO2 maintained jejunal mucosal perfusion, probably as a result of hypercarbia as N2 at equal pressures reduced mesenteric flow. The vasodilator NO provided no haemodynamic benefit.

Neural stem cells in the adult human brain

New neurons are continuously generated in certain regions of the adult brain. Studies in rodents have shown that new neurons are generated from self-renewing multipotent neural stem cells. Here we demonstrate that both the lateral ventricle wall and the hippocampus of the adult human brain harbor self-renewing cells capable of generating neurons, astrocytes, and oligodendrocytes in vitro, i.e., bona fide neural stem cells.

The immunohistochemical expression of DNA-PKCS and Ku (p70/p80) in head and neck cancers: relationships with radiosensitivity

PURPOSE

The DNA-PK complex is one of the major pathways by which mammalian cells respond to DNA double-strand breaks induced by ionizing radiation. This study evaluated the relationship between the immunohistochemical expression of the individual components of DNA-PK and cellular radiosensitivity in head and neck cancers.

METHODS AND MATERIALS

Biopsies from patients with previously untreated squamous cell carcinomas of the head and neck were assessed for inherent tumor radiosensitivity measured as the surviving fraction at 2 Gy (SF2) using a soft agar clonogenic assay. Paraffin-embedded tumor material from 64 successfully grown specimens was immunohistochemically stained for expression of DNA-PKcs and Ku (p70/p80). The same tumor material was previously analyzed for the immunohistochemical expression of p53.

RESULTS

A significant correlation was found between the degree of expression of DNA-PKcs and Ku (p70/p80) (r = 0.55, p<0.001). There were no overall significant differences in the levels of expression of DNA-PKcs and Ku (p70/p80) in tumors from patients of either sex, different sites, histologies, and stages. No relationship was found between SF2 and the expression of either DNA-PKcs (r = 0.22, p = 0.081) or Ku (p70/p80) (r = 0.064, p = 0.62). Comparison with previous immunohistochemical characterization showed no significant correlations between the expression levels of p53 and either DNA-PKcs (r = 0.093, p = 0.46) or Ku (p70/p80) (r = -0.17, p = 0.17).

CONCLUSIONS

This study suggests that determining the immunohistochemical expression of DNA-PK in head and neck cancers from multiple sites does not have a role as a predictive assay of tumor in vitro radiosensitivity.

Glial responses to synaptic damage and plasticity

We review three principally different forms of injury-induced synaptic alterations. (1) Displacement of presynaptic terminals from perikarya and dendrites of axotomized neurons, (2) central changes in primary afferent terminals of peripherally axotomized sensory ganglion cells, and (3) anterograde Wallerian-type degeneration following interruption of central axonal pathways. All these instances rapidly activate astrocytes and microglia in the vicinity of the affected synaptic terminals. The evidence suggests that activated astrocytes play important and direct roles in synapse elimination and in the processes mediating collateral reinnervation. The roles of microglia are enigmatic. They undergo activation close to axotomized motoneuron perikarya, where synapse displacement occurs, but not adjacent to axotomized intrinsic central nervous system neurons, where synapse displacement also occurs. Microglia are also rapidly activated around central primary sensory terminals of peripherally axotomized sensory ganglion cells. Occasional phagocytosis of degenerating axon terminals by microglia occur in the latter situation. However, the role of microglia may be more oriented toward the general tissue conditions rather than specifically toward synaptic terminals.

Properties of spin and fluorescent labels at a receptor-ligand interface

Site-directed labeling was used to obtain local information on the binding interface in a receptor-ligand complex. As a model we have chosen the specific association of the extracellular part of tissue factor (sTF) and factor VIIa (FVIIa), the primary initiator of the blood coagulation cascade. Different spectroscopic labels were covalently attached to an engineered cysteine in position 140 in sTF, a position normally occupied by a Phe residue previously characterized as an important contributor to the sTF:FVIIa interaction. Two spin labels, IPSL [N-(1-oxyl-2,2,5, 5-tetramethyl-3-pyrrolidinyl)iodoacetamide] and MTSSL [(1-oxyl-2,2,5, 5-tetramethylpyrroline-3-methyl)methanethiosulfonate], and two fluorescent labels, IAEDANS [5-((((2-iodoacetyl)amino) ethyl)amino)naphthalene-1-sulfonic acid] and BADAN [6-bromoacetyl-2-dimethylaminonaphthalene], were used. Spectral data from electron paramagnetic resonance (EPR) and fluorescence spectroscopy showed a substantial change in the local environment of all labels when the sTF:FVIIa complex was formed. However, the interaction was probed differently by each label and these differences in spectral appearance could be attributed to differences in label properties such as size, polarity, and/or flexibility. Accordingly, molecular modeling data suggest that the most favorable orientations are unique for each label. Furthermore, line-shape simulations of EPR spectra and calculations based on fluorescence depolarization measurements provided additional details of the local environment of the labels, thereby confirming a tight protein-protein interaction between FVIIa and sTF when the complex is formed. The tightness of this local interaction is similar to that seen in the interior of globular proteins.

The novel pyrrolopyrimidine PNU-101033-E improves facial motor neuron survival following intracranial axotomy of the facial nerve in the adult rat

Neuronal survival is important to functional restitution following axotomy. Proximal lesions of the facial nerve, due to head trauma or tumor growth, for example, may cause long-standing or even permanent facial nerve palsy. Betamethasone has been used by several neurosurgical clinics for the treatment of postoperative facial nerve palsy; however, this practice is based only on clinical experience. The aim of the present study was to explore the putative effect on facial motor neuron survival of a novel lazaroid (pyrrolopyrimidine, PNU-101033-E) and furthermore to compare the effects with those of betamethasone, following intracranial transection of the facial nerve in adult rats. Both agents are known to inhibit lipid peroxidation by free radical scavenging. The lesion model used has recently been reported to induce massive neuronal cell death with a relative survival of 26.8 +/- 11.3% 1 month after lesion. Oral administration of lazaroids or daily injections of betamethasone followed surgery for 1 month, after which quantification of motor neuronal profiles was performed in the facial nucleus. Lazaroid-treated animals showed a significantly enhanced neuronal survival (68.0 +/- 9.8%), whereas no significant difference was found in betamethasone-treated animals (33.1 +/- 11.7%). The microglial and astrocytic responses in the facial nucleus were intense on the operated sides in betamethasone-treated as well as lazaroid-treated animals, and no differences in comparison with untreated animals were found. In conclusion, we found that the novel pyrrolopyrimidine PNU-101033-E, but not betamethasone, significantly enhanced nerve cell survival. This agent may therefore serve as a useful neuroprotective agent following intracranial trauma to the facial nerve and should be further evaluated for clinical use.

Hereditary absence of complement C5 in adult mice influences Wallerian degeneration, but not retrograde responses, following injury to peripheral nerve

We have examined the role of complement component 5 (C5) in peripheral nerve fiber degeneration and regeneration, as well as in glial and neuronal cell responses in the central nervous system (CNS). Adult congenic mice lacking C5 (C5(-)) and the corresponding normal strain (C5(+)) were used. Macrophage recruitment as well as axonal and myelin sheath elimination were delayed from 1 to 21 days postinjury in C5(-) mice compared to the C5(+) group after sciatic nerve crush. Despite this, recovery of motor function was not delayed. In the CNS, microglial cells and astrocytes responded in the same way from 3 to 21 days after sciatic nerve injury in C5(-) and C5(+) mice, and the extent of neuron death following hypoglossal nerve avulsion was the same in both groups. These findings suggest that C5 and/or its derivatives play an important role in initiating the recruitment of macrophages to the injured nerve and, probably indirectly, in early remyelination of regenerating axons, but does not influence the longterm functional restoration or axotomy-induced nerve cell death. C5-derived molecules do not appear to participate in central glial cell responses to peripheral nerve injury. These findings elucidate new aspects on the functional role of the complement system in the peripheral nervous system following peripheral nerve injury.

Extensive neuronal cell death following intracranial transection of the facial nerve in the adult rat

The aim of the present study is to examine the neuronal degeneration and the glial response following intracranial transection of the facial nerve close to the brainstem and furthermore to compare the results with a distal nerve injury. The facial nerve was cut either intracranially in the posterior cranial fossa or further distally, where it passes the parotid gland, in adult rats. Intracranial axotomy caused a massive loss of neuronal profiles. Only 26.8+/-11.3% of facial motor neuronal profiles were found ipsilateral to the nerve injury when compared to the contralateral side, following intracranial axotomy. This was statistically significant in comparison to the distal injury (72.4+/-9.5%), 4 weeks post-lesion. Reactive microglial cells expressed ED1 immunoreactivity following the intracranial axotomy but not following the distal nerve injury. In conclusion, there was a large discrepancy in neuronal degeneration as well as presence of phagocytic (ED1 positive) microglia between the two lesions. The intracranial lesion model used in the present study generates a massive neuronal cell death and should therefore be a useful tool for studies on proximal cranial nerve injuries and in particular mechanisms causing cell death, which may occur following, for example, head trauma.

The lack of correlation between proliferation (Ki-67, PCNA, LI, Tpot), p53 expression and radiosensitivity for head and neck cancers

A study was made of the relationship between measurements of radiosensitivity versus proliferation and p53 status in head and neck cancers. Inherent tumour radiosensitivity was assessed as surviving fraction at 2 Gy (SF2) using a clonogenic soft agar assay (n = 77). The results were compared to data on proliferation obtained by both flow cytometry (labelling index (LI), the potential doubling time (Tpot) n = 55) and immunohistochemistry (Ki-67 and PCNA; n = 68), together with immunohistochemical p53 expression (n = 68). There were no overall significant differences in the median values of the various parameters analysed for the different sites within the head and neck region, disease stages, grades of tumour differentiation or nodal states. A subgroup analysis showed that oropharyngeal (n = 22) versus oral cavity (n = 35) tumours were more radiosensitive (P = 0.056) and had a higher Ki-67 index (P = 0.001). Node-positive tumours had higher LI (P = 0.021) and a trend towards lower Tpot (P = 0.067) values than node-negative ones. No correlations were seen between SF2 and any of the parameters studied. The long-standing dogma of an increased radiosensitivity of rapidly proliferating cells in contrast to slowly proliferating cells was not confirmed. The study shows that parallel measurements of different biological markers can be obtained for a large number of patients with head and neck cancers. The independence of the various parameters studied suggests that there may be potential for their combined use as prognostic factors for the outcome of radiotherapy.

Effect of Q10 supplementation on tissue Q10 levels and adenine nucleotide catabolism during high-intensity exercise

The aim of the present study was to investigate the concentration of ubiquinone-10 (Q10), at rest, in human skeletal muscle and blood plasma before and after a period of high-intensity training with or without Q10 supplementation. Another aim was to explore whether adenine nucleotide catabolism, lipid peroxidation, and mitochondrial function were affected by Q10 treatment. Seventeen young healthy men were assigned to either a control (placebo) or Q10-supplementation (120 mg/day) group. Q10 supplementation resulted in a significantly higher plasma Q10/total cholesterol level on Days 11 and 20 compared with Day 1. There was no significant change in the concentration of Q10 in skeletal muscle or in isolated skeletal muscle mitochondria in either group. Plasma hypoxanthine and uric acid concentrations increased markedly after each exercise test session in both groups. After the training period, the postexercise increase in plasma hypoxanthine was markedly reduced in both groups, but the response was partially reversed after the recovery period. It was concluded that Q10 supplementation increases the concentration of Q10 in plasma but not in skeletal muscle.