The genetic landscape of mitochondrial diseases in the next-generation sequencing era: a Portuguese cohort study.

Introduction: Rare disorders that are genetically and clinically heterogeneous, such as mitochondrial diseases (MDs), have a challenging diagnosis. Nuclear genes codify most proteins involved in mitochondrial biogenesis, despite all mitochondria having their own DNA. The development of next-generation sequencing (NGS) technologies has revolutionized the understanding of many genes involved in the pathogenesis of MDs. In this new genetic era, using the NGS approach, we aimed to identify the genetic etiology for a suspected MD in a cohort of 450 Portuguese patients. Methods: We examined 450 patients using a combined NGS strategy, starting with the analysis of a targeted mitochondrial panel of 213 nuclear genes, and then proceeding to analyze the whole mitochondrial DNA. Results and Discussion: In this study, we identified disease-related variants in 134 (30%) analyzed patients, 88 with nuclear DNA (nDNA) and 46 with mitochondrial DNA (mtDNA) variants, most of them being pediatric patients (66%), of which 77% were identified in nDNA and 23% in mtDNA. The molecular analysis of this cohort revealed 72 already described pathogenic and 20 novel, probably pathogenic, variants, as well as 62 variants of unknown significance. For this cohort of patients with suspected MDs, the use of a customized gene panel provided a molecular diagnosis in a timely and cost-effective manner. Patients who cannot be diagnosed after this initial approach will be further selected for whole-exome sequencing. Conclusion: As a national laboratory for the study and research of MDs, we demonstrated the power of NGS to achieve a molecular etiology, expanding the mutational spectrum and proposing accurate genetic counseling in this group of heterogeneous diseases without therapeutic options.

TGFß activating integrins ß6 and ß8 are dysregulated in inflammatory skin disease and cutaneous melanoma.

BACKGROUND: Integrins avß6 and avß8 are expressed by keratinocytes and transactivate latent TGFß. In a murine model, integrin mediated activation of TGFß has been shown to be critical in maintaining skin homeostasis, specifically playing roles in epidermal retention of Langerhans cells and resident memory cells T cells (Trm). OBJECTIVE: We examine expression of Integrins ß6 and ß8 in human skin, inflammatory skin disease, benign nevi, and melanoma and hypothesize that integrin expression is dysregulated in disease. METHODS: Using immunohistochemistry, we stained tissue from normal human skin (n = 8), psoriasis (n = 6), atopic dermatitis (n = 6), lichen planus (n = 5), benign nevi (n = 24), and melanoma (n = 25) with anti-integrin ß6 and anti-integrin ß8 to survey expression pattern. We also performed a retrospective chart review in the melanoma cohort to examine if integrin ß6 and ß8 expression was associated with increased Breslow depth and worse prognostic staging. RESULTS: Here, we show that human keratinocytes express integrins ß6 and ß8, similar to murine keratinocytes. We also found that inflammatory skin conditions have increased Integrin ß6, but not Integrin ß8 expression. Furthermore, we identified that melanomas have greatly increased expression of integrin ß8 compared to nevi. Additionally, high expression of integrin ß8 was correlated with greater Breslow depth at diagnosis and with worse prognostic staging. CONCLUSION: These findings demonstrate that like murine keratinocytes, human keratinocytes express integrin ß6 and ß8 under steady state conditions. Moreover, altered integrin expression may participate in the development or maintenance of cutaneous inflammation as well as tumor immune evasion.

TNF-α and IL-1ß Do Not Induce Langerhans Cell Migration by Inhibiting TGFß Activation.

In the skin, Langerhans cells (LCs) require autocrine latent TGFß that is transactivated by the integrins ανß6 and ανß8 expressed by keratinocytes (KCs) for long-term epidermal retention. Selective expression of a ligand-independent, constitutively active form of TGFßR1 inhibits LC migration during homeostasis and in response to UVB exposure. In this study, we found that LC migration in response to inflammatory stimuli was also inhibited by ligand-independent TGFßR1 signaling. Contrary to UVB stimulation, which reduced KC expression of ανß6, in vitro and in vivo exposure to TNF-α or IL-1ß increased ανß6 transcript and protein expression by KCs. This resulted in increased KC-mediated transactivation of latent TGFß. Expression of ανß8 was largely unchanged. These findings show that ligand-independent TGFßR1 signaling in LCs can overcome inflammatory migration stimuli, but reduced KC-mediated transactivation of latent TGFß by KCs may only drive LC migration during homeostasis and in response to UV stimulation.

Competition for Active TGFß Cytokine Allows for Selective Retention of Antigen-Specific Tissue- Resident Memory T Cells in the Epidermal Niche.

Following antigen-driven expansion in lymph node, transforming growth factor-ß (TGFß) is required for differentiation of skin-recruited CD8+ T cell effectors into epidermal resident memory T (Trm) cells and their epidermal persistence. We found that the source of TGFß -supporting Trm cells was autocrine. In addition, antigen-specific Trm cells that encountered cognate antigen in the skin, and bystander Trm cells that did not, both displayed long-term persistence in the epidermis under steady-state conditions. However, when the active-TGFß was limited or when new T cell clones were recruited into the epidermis, antigen-specific Trm cells were more efficiently retained than bystander Trm cells. Genetically enforced TGFßR signaling allowed bystander Trm cells to persist in the epidermis as efficiently as antigen-specific Trm cells in both contexts. Thus, competition between T cells for active TGFß represents an unappreciated selective pressure that promotes the accumulation and persistence of antigen-specific Trm cells in the epidermal niche.

Langerhans Cells Spy on Keratinocytes.

Tunneling nanotubes (TNTs) have been described as a novel mechanism for intercellular communication. However, the ability of epidermal cells to utilize TNTs remains a mystery. In this issue, Su and Igyártó (2019) showed that Langerhans cells (LCs) obtain mRNA from keratinocytes (KC) in vivo presumably via TNTs. The demonstration of exchange of genetic material from KC to LC in vivo is an an unexpected method of antigen acquisition by LC and also an important consideration when analyzing transcriptomic data.

Langerhans Cells Sense Staphylococcus aureus Wall Teichoic Acid through Langerin To Induce Inflammatory Responses.

Staphylococcus aureus is a major cause of skin and soft tissue infections and aggravator of the inflammatory skin disease atopic dermatitis (AD [eczema]). Epicutaneous exposure to S. aureus induces Th17 responses through skin Langerhans cells (LCs), which paradoxically contribute to host defense but also to AD pathogenesis. The molecular mechanisms underlying the interaction between S. aureus and LCs are poorly understood. Here we demonstrate that human LCs directly interact with S. aureus through the pattern recognition receptor langerin (CD207). Human, but not mouse, langerin interacts with S. aureus through the conserved ß-N-acetylglucosamine (GlcNAc) modifications on wall teichoic acid (WTA), thereby discriminating S. aureus from other staphylococcal species. Importantly, the specific S. aureus WTA glycoprofile strongly influences the level of proinflammatory cytokines that are produced by in vitro-generated LCs. Finally, in a murine epicutaneous infection model, S. aureus strongly upregulated transcripts of Cxcl1, Il6, and Il17, which required the presence of both human langerin and WTA ß-GlcNAc. Our findings provide molecular insight into the unique proinflammatory capacities of S. aureus in relation to skin inflammation.IMPORTANCE The bacterium Staphylococcus aureus is an important cause of skin infections and is also associated with the occurrence and severity of eczema. Langerhans cells (LCs), a specific subset of skin immune cells, participate in the immune response to S. aureus, but it is yet unclear how LCs recognize S. aureus Therefore, we investigated the molecular mechanism underlying the interaction between LCs and S. aureus We identified that wall teichoic acid, an abundant polymer on the S. aureus surface, is recognized by langerin, a receptor unique to LCs. This interaction allows LCs to discriminate S. aureus from other related staphylococcal species and initiates a proinflammatory response similar to that observed in patients with eczema. Our data therefore provide important new insights into the relationship between S. aureus, LCs, and eczema.

Anaemia in pregnancy: associations with parity, abortions and child spacing in primary healthcare clinic attendees in Trinidad and Tobago.

OBJECTIVE: To determine the prevalence of anaemia in antenatal clinic attendees; to investigate the effects of parity, age, gravidity, previous abortions, child spacing and other factors on the prevalence of anaemia in pregnancy. METHODS: This was a retrospective and cross-sectional study. Antenatal records of 2287 pregnant women attending 40 public healthcare centres from January 2000 to December 2005 in Trinidad and Tobago were used. Data pertaining to the investigated variables were recorded. The national prevalence of anaemia was calculated and chi-square tests, odds ratios and logistic regression were used to assess the relationship between anaemia and each variable. RESULTS: The prevalence of anaemia was 15.3% (95% CI 13.4%, 16.6%). No significant difference in the prevalence of anaemia was found among the different clinics or counties. At the first haemoglobin reading, age was inversely related to the presence of anaemia, whereas gestational age at first visit was directly related. At the final haemoglobin reading, parity, gravidity, and previous spontaneous abortions were directly related to the prevalence of anaemia, while the number of visits was inversely related. Age was inversely associated to the severity of anaemia while gravidity was directly related. CONCLUSION: The prevalence of anaemia decreased by 18.7% from 1967. Despite this positive indication, women under 24 years and those commencing antenatal care after the first trimester are still at a higher risk for developing anaemia. Early commencement of antenatal care and close monitoring of the risk groups identified should be strongly advocated.

Anaemia in pregnancy: associations with parity, abortions and child spacing in primary healthcare clinic attendees in Trinidad and Tobago

OBJECTIVE: To determine the prevalence of anaemia in antenatal clinic attendees; to investigate the effects of parity, age, gravidity, previous abortions, child spacing and other factors on the prevalence of anaemia in pregnancy. METHODS: This was a retrospective and cross-sectional study. Antenatal records of 2287 pregnant women attending 40 public healthcare centres from January 2000 to December 2005 in Trinidad and Tobago were used. Data pertaining to the investigated variables were recorded. The national prevalence of anaemia was calculated and chi-square tests, odds ratios and logistic regression were used to assess the relationship between anaemia and each variable. RESULTS: The prevalence of anaemia was 15.3% (95% CI 13.4%, 16.6%). No significant difference in the prevalence of anaemia was found among the different clinics or counties. At the first haemoglobin reading, age was inversely related to the presence of anaemia, whereas gestational age at first visit was directly related. At the final haemoglobin reading, parity, gravidity, and previous spontaneous abortions were directly related to the prevalence of anaemia, while the number of visits was inversely related. Age was inversely associated to the severity of anaemia while gravidity was directly related. CONCLUSION: The prevalence of anaemia decreased by 18.7% from 1967. Despite this positive indication, women under 24 years and those commencing antenatal care after the first trimester are still at a higher risk for developing anaemia. Early commencement of antenatal care and close monitoring of the risk groups identified should be strongly advocated.

Leishmanial antigens in the diagnosis of active lesions and ancient scars of American tegumentary leishmaniasis patients

Cutaneous biopsies (n = 94) obtained from 88 patients with American tegumentary leishmaniasis were studied by conventional and immunohistochemical techniques...

Predicting outcome in hypoxic-ischemic brain injury.

Predicting the neurologic outcome of children after a hypoxic-ischemic event continues to be a challenge for intensivists and pediatric neurologists. Nevertheless, with accurate history taking, serial neurologic examination, and some ancillary studies, the clinician can predict accurately whether a child will die or have profound neurologic damage. Aggressive resuscitation should be offered to all children when found in CPA. A simple ingestion might have led to this clinical scenario, and complete neurologic recovery may be possible if effective resuscitation is implemented. In cases of drowning, several factors, if present, are consistent with profound neurologic sequelae or death. These include prolonged submersions with asystole, delayed onset of CPR, no spontaneous respirations on arrival to the emergency department, and low initial pH value. The options of withdrawal of life support or a DNR status should be offered to families of children who have survived a devastating hypoxic-ischemic event but who are in a PVS. If brain-death criteria have been fulfilled, the patient must then be disconnected from life support after organ donation has been discussed with the family.

Thiazolidinediones increase plasma-adipose tissue FFA exchange capacity and enhance insulin-mediated control of systemic FFA availability.

We studied the effects of thiazolidinedione treatment (rosiglitazone 1 or 10 micromol.kg(-1).day(-1) or darglitazone 1.3 micromol.kg(-1).day(-1) for 3 weeks) on lipid metabolism in obese Zucker rats. In the basal 7-h fasted state, rosiglitazone (10 micromol.kg(-1).day(-1)) and darglitazone corrected the hypertriglyceridemia by increasing plasma triglyceride (TG) clearance and decreasing hepatic TG production, as assessed using Triton WR 1339. Free fatty acid (FFA) metabolism was assessed using 3H-palmitate tracer by estimating rates of plasma FFA appearance (Ra), whole-body FFA oxidation (Rox), and tissue-specific nonoxidative FFA disposal (Rfs). Basal Ra, plasma FFA levels, and clearance were increased by both thiazolidinediones. Detailed studies were conducted with darglitazone, which under basal conditions increased Ra (+114%), Rox (+51%), and Rfs in adipose tissues. During euglycemic clamps performed at insulin levels corresponding to those observed postprandially, darglitazone increased the glucose infusion rate from 4.7 to 13.3 mg.min(-1) and, in contrast to the basal state, it decreased Ra (-67%), Rox (-84%), and Rfs in adipose tissue, muscle, and liver. We concluded that thiazolidinediones 1) ameliorate hypertriglyceridemia by lowered hepatic TG production and augmented TG clearance (two separate kinetic effects), 2) enhance insulin-mediated suppression of systemic FFA mobilization while increasing the capacity to mobilize FFA during fasting, 3) increase FFA trafficking into adipose tissue by increasing the ability of adipose tissue to take up and store FFA, and 4) enhance metabolic flexibility by improving glucoregulation under hyperinsulinemic conditions (possibly involving reduced skeletal muscle and liver exposure to fatty acids) and augmenting the capacity to utilize FFAs during fasting.

Epinephrine in irrigating solutions and its effect on blood pressure and pulse rates

A study was done to determine if epinephrine 1:600,000 concentration mixed with BSS will have any effect on a patients cardiovascular status during and after cataract surgery. A retrospective study was done on 50 cataract patients from January to June 1999. 0.3ml of epinephrine added to 500cc of BSS were used as the irrigating solution for phacoemulsification. Phacoemulsification using the pre-slice technique under topical anesthesia was performed on all patients. Irrigation and aspiration was done and small amounts of solution to reform the chamber. Patients blood pressure and pulse rates were taken preoperatively, intra-operatively, post-operatively and 24 hrs. post-operatively. Results showed no statistically significant rise in systolic blood pressure and pulse rates. We conclude that epinephrine 1:600,000 mixture in BSS is a safe way of maintaining pupillary dilatation during phacoemulsification. (Author)

Enhanced renal vascular responsiveness to angiotensin II in hypertensive ren-2 transgenic rats.

The present study was performed to evaluate renal vascular responsiveness (RVR) to ANG II in hypertensive transgenic rats [TGR; strain TGR(mRen2)27] harboring the mouse ren-2 renin gene. Renal blood flow (RBF) responses to either intravenous or intrarenal arterial administration of ANG II were assessed in pentobarbital sodium-anesthetized female heterozygous TGR (9-12 wk old) and age-matched transgene-negative Hanover Sprague-Dawley rats (HanSD). Intravenous bolus injections of 15 and 30 ng ANG II elicited dose-dependent increases in mean arterial blood pressure (AP) and decreases in RBF in both TGR and HanSD. However, the magnitude of the increases in AP was greater in TGR than in HanSD (24 +/- 1 vs. 17 +/- 2 mmHg and 33 +/- 2 vs. 25 +/- 1 mmHg, respectively, P < 0.05 in both cases). Similarly, the magnitude of the decrease in RBF elicited by intravenous administration of 15 ng of ANG II was greater in TGR than HanSD (-62 +/- 3 vs. -52 +/- 5%, P < 0.05). Intrarenal arterial administration of 1.5 and 3 ng ANG II did not alter mean AP in either group but elicited larger decreases in RBF in TGR than in HanSD (-24 +/- 2 vs. -13 +/- 1% and -41 +/- 5 vs. -30 +/- 2%, respectively, P < 0.05 in both cases). In contrast, intrarenal arterial administration of norepinephrine (40 and 80 ng) elicited smaller decreases in RBF in TGR than in HanSD (-24 +/- 3 vs. -40 +/- 6% and -51 +/- 9 vs. -71 +/- 8%, respectively, P < 0.05 in both cases), indicating that TGR do not exhibit a generalized increase in RVR to endogenous vasoconstrictors. Furthermore, the enhanced RVR to ANG II does not appear to reflect an impaired RVR to endogenous vasodilator factors since intrarenal administration of bradykinin and acetylcholine elicited larger increases in RBF in TGR than in HanSD. The present findings indicate that hypertensive TGR exhibit exaggerated renal and peripheral vascular responses to ANG II, which likely contributes to an increased renal and peripheral vascular resistance and thereby to the hypertension in TGR.

Proximal tubular fluid, kidney, and plasma levels of angiotensin II in hypertensive ren-2 transgenic rats.

The present study was performed to assess the plasma and kidney levels of angiotensin I (ANG I) and ANG II during prehypertensive (4- to 5-wk old), development (6- to 8-wk old), and maintenance (10- to 12-wk old) phases of hypertension in pentobarbital-anesthetized transgenic rats [TGR; strain name: TGR(mRen2)27] and age-matched transgene-negative Hannover Sprague-Dawley rats (HanSD). At 4-5 wk, mean arterial pressures of TGR were not different from those of HanSD (110 +/- 5 vs. 114 +/- 4 mmHg). However, mean arterial pressures of 6-8 wk and 10-12 wk TGR were higher than those of HanSD (179 +/- 3 vs. 110 +/- 6 and 173 +/- 5 vs. 116 +/- 3 mmHg, respectively; P < 0.01 in both cases). Plasma ANG II levels in 4-5 wk and 6-8 wk TGR were not different from those in HanSD (70 +/- 11 vs. 66 +/- 7 and 60 +/- 8 vs. 48 +/- 12 fmol/ml, respectively). However, plasma ANG II levels in 10-12 wk TGR were higher than those in HanSD (125 +/- 26 vs. 38 +/- 12 fmol/ml, P < 0.01). Kidney ANG II levels in 4-5 wk, 6-8 wk, and 10-12 wk TGR averaged 370 +/- 57, 247 +/- 16, and 562 +/- 86 fmol/g, respectively, values not different from those in HanSD. In additional studies performed on 6-8 wk TGR and HanSD, multiple free-flow proximal tubular fluid collections were obtained and pooled for each animal. In these experiments, mean arterial pressures of the 10 TGR and 7 HanSD studied averaged 178 +/- 9 and 129 +/- 3 mmHg (P < 0.01), respectively. The ANG II concentration in proximal tubular fluid obtained from TGR averaged 5.6 +/- 2.1 pmol/ml (n = 10), a value not different from that in proximal tubular fluid collected from HanSD (5.3 +/- 2.8 pmol/ml, n = 7). However, the ANG II contents of the micropunctured left kidney and the nonmicropunctured right kidney of TGR were lower than those in HanSD (690 +/- 95 vs. 1,374 +/- 210 and 659 +/- 119 vs. 1,303 +/- 196 fmol/g, respectively; P < 0.01 in both cases). The present findings indicate that proximal tubular fluid of hypertensive TGR contains nanomolar concentrations of ANG II and that proximal tubular fluid, plasma and kidney ANG II levels in anesthetized hypertensive TGR are not markedly suppressed compared with those in normotensive control rats.

Application of computer-assisted morphometry to the analysis of prenatal development of human lung.

Morphometry is well-established in tumour pathology. To evaluate is potential usefulness for description of developmental processes, histological slides from paraffin-embedded specimens of 67 human fetal lungs were Feulgen-stained, and morphometric characteristics of nuclei of epithelial pulmonary cells were analysed with an automated image analysis system. The measured cytometric features comprised of integrated optical density (IOD), S-phase-related IOD fraction, IOD entropy and nuclear area. Histometric features of the specimens were based upon the minimum spanning tree (MST) and included distances between neighboring epithelial cells, between epithelial cells and neighboring lymphocytes, and assessment of MST entropy. Notably, certain parameters revealed a non-uniform level during prenatal development S-phase-related IOD fraction increased from 5% to 8% between 14 and 16 weeks of gestation, then declined to 6% until birth. The IOD entropy steadily increased during development, whereas the extent of nuclear area remained constant. In accordance with an increase of the S-phase-related fraction the MST entropy displayed a singular peak between 14 and 16 weeks of gestation, which is probably associated with development of glandular structures in the lung. Correlation of expression of binding sites for markers, presumably involved in functional aspects of development, with such alterations, is shown for binding capacities of biotinylated fucoidan and the S-phase-related fraction. This may be helpful to infer immuno- or ligando histochemically defined tissue sites with potential physiological significance in morphometrically distinguished periods of development.

Efficacy and mechanisms of dopexamine in the prevention of ischemia-reperfusion induced organ damage: role of oxygen free radicals.

The studies reported in this article provide evidence that several complex mechanisms are involved in the ability of dopexamine HCl (DPX) in preventing ischemia-reperfusion induced organ damage. In a canine model of hemorrhagic shock in which shed-blood was reinfused, DPX prevented deterioration in renal blood flow via an action on beta-2 and DA-1 receptors, whereas its ability to preserve tubular function was essentially due its agonistic effects on DA-1 receptors. In a different experimental model in anesthetized rats, acute generation of oxygen free radicals (OFR) via intravenous administration of Xanthine (X) followed by Xanthine Oxidase (XO) resulted in depression of circulation and death of more than 80% of the animals within the observation period of 120 min. Pretreatment of the rats with DPX significantly enhanced survival rate in a dose dependent manner to about 70%. Neither dobutamine nor prenalterol, which are beta-1 adrenoceptor agonists and like DPX, potent chronotropic and inotropic agents were effective in preventing OFR induced lethal toxicity. In a separate series, a selective DA-1 receptor agonist felodopam had no protective effect and a DA-1 receptor antagonist SCH-23390 failed to antagonize the salutary effects of DPX. In contrast, salbutamol, a selective beta-2 adrenoceptor agonist significantly promoted the survival rate facilitated by DPX and a selective beta-2 adrenoceptor antagonist, ICI-558,551 significantly attenuated the survival rate. These later studies suggest that unlike in hemorrhagic shock, the beta-2 adrenoceptor agonistic properties are critical in the ability of DPX to attenuate lethal toxicity and these effects could be related to prevention of lipid peroxidation induced by oxygen free radicals.

Effect of pharmacological interventions in the prevention of lipid peroxidation and respiratory depression induced by oxygen free radicals in anesthetized rats.

We have recently reported that in an anesthetized rat model, generation of oxygen free radicals (OFR) via i.v. administration of Xanthine plus Xanthine Oxidase [X + XO] resulted in death of about 90% of the animals within a 120-min observation period. Pretreatment of the rats with endogenous scavengers Superoxide Dismutase and Catalase, or with felodipine, a dihydropyridine calcium channel blocker, and/or with dopexamine, an agonist of beta 2 adrenoceptors as well as dopamine (DA-1) receptors significantly enhanced the survival rate to over 70%. The present study was designed to investigate whether lipid peroxidation and ensuing respiratory depression contributed to the lethal toxicity of the free radicals. In the control group, the death of the rats administered [X + XO] was proceeded by significant increases in the plasma lipid peroxides (PLP) and by a severe hypertensive response characteristic of an intense ischemic state, which was confirmed by the presence of hypercapnia, hypoxemia, and acidosis. Placement of the animals on the positive pressure ventilation prior to the administration of [X + XO] did not prevent increases in PLP but, prevented any adverse alterations in the respiratory markers and significantly enhanced survival rate up to 70%. In contrast, both felodipine as well as dopexamine prevented any increases in PLP, normalized blood gas profile, and significantly increased survival rate to 80 to 90%. These observations suggest that the lethal toxicity produced by oxygen free radical was due to respiratory distress. The relationship between increases in the PLP and respiratory depression and the mechanisms via which two pharmacologically distinct agents, felodipine and dopexamine, facilitated the salutary effects cannot be conclusively stated at this time. It is further suggested that although the doses of these two drugs employed in the present studies are not adequate to function as antioxidants, such a possibility cannot be entirely ruled out.

Studies on the pharmacological interventions to prevent oxygen free radical (OFR)-mediated toxicity; effects of dopexamine, a DA1 receptor and beta 2 adrenoceptor agonist.

We have previously demonstrated that the lethal effects of free radicals generated by intravenous administration of Xanthine (X: 0.225 mg kg-1) and Xanthine Oxidase (XO: 5 u kg-1) were prevented by calcium channel blockers such as felodipine (a dihydropyridine calcium antagonist) and verapamil. These studies have implicated that there may be potential interactions between free radicals and cell calcium. However, alternate mechanisms such as hemodynamic changes in the overall effects of calcium antagonists cannot be ruled out. Therefore, the present studies are conducted to further investigate the efficacy of various cardiovascular agents such as Dopexamine (DPX) on [X+XO]-induced mortality. Intravenous administration of [X+XO] to anesthetized rats produced a rapid decrease in blood pressure and a mortality rate of over 90%. Pretreatment with dopexamine, a dopamine receptor (DA1) and beta 2 adrenoceptor agonist significantly enhanced survival upto 70%. Neither dobutamine nor prenalterol, (preferential beta 1 agonists) both of which produced similar increases in heart rate as DPX, enhanced survival rate thus suggesting that cardiac stimulation alone, did not contribute to the protective effects of DPX. Likewise, fenoldopam, a DA1 agonist and a vasodilator also failed to have any significant protective effect on [X+XO]-induced mortality suggesting that the DA1 receptor activation alone cannot account for the salutary effects of dopexamine. Pretreatment of the rats with Salbutamol, a preferential beta 2 agonist significantly enhanced survival upto 50% and a beta 2 antagonist ICI 118,551 significantly attenuated the ability of dopexamine to promote survival.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell type-dependent alterations of binding of synthetic blood group antigen-related oligosaccharides in lung cancer.

Blood group antigen-related oligosaccharides have been implicated in growth regulation, cell mobility control and adhesion; we are therefore interested in the localization of receptors for these oligosaccharides in tumour cells. Labelled neoglycoconjugates that carry synthetic sugar structures are suitable tools to determine: whether such binding sites are present in human lung cancer; whether structural alterations of the glycoligand part will affect extent of binding; and whether cell type-associated alterations can be detected. Sections from 121 cases of lung cancer, representing small cell and non-small cell lung carcinoma, mesothelioma and metastases from extrapulmonary primary carcinomas were used to study the binding of nine synthetic AH- and Le-related oligosaccharides. Probes with fucose-alpha 1-3/4-N-acetylglucosamine-beta 1-R, an A-like disaccharide and 3'-sulfated galactose as ligand appear to bind less well to small cell than to non-small cell lung cancer cases, whereas Lec-disaccharide distinguishes mesothelioma from metastatic carcinoma. The latter ligand, A-like disaccharide and H (type III)-like trisaccharide exhibit evident cell type-associated differences in extent of binding. Thus, tailor-made neoglycoconjugates constitute a promising class of histopathological tools that warrants further study.

Comparative evaluation of the acute effects of oxygen free radicals on myocardial contractility in anesthetized dogs with those occurring in the early stages of splanchnic artery occlusion and hemorrhagic shock.

Oxygen free radicals are cytotoxic and generated in excessive quantities during reoxygenation of ischemic organs. It has been demonstrated that oxygen free radicals impair cardiac contractile mechanisms in in vitro studies as well as depress myocardial contractility in in vivo experiments. The objectives of the present studies are to evaluate alterations in cardiac contractility and hemodynamics in two canine models of shock, namely, Wigger's model of hemorrhage and splanchnic artery occlusion (SAO) model. The data obtained in these models are comparatively evaluated with that caused by oxygen free radicals. Pentobarbital anesthetized dogs were instrumented to record blood pressure, heart rate, left ventricular pressure, (LVP & LVEDP) and LVdp/dt. Contractility index was evaluated as max dp/dt.p. In the Wigger's model, during the period of hemorrhage or after reinfusion of the shed blood despite marked variations in preload and afterload, index of contractility was not altered. Similarly, in the SAO model also, during the period of occlusion or after release, contractility index was not depressed. However, in both the models, after reinfusion of the blood (Wigger's) or after release of splanchnic arteries, there were gradual deteriorations of stroke volume, cardiac output, and arterial blood pressure. In contrast, after generation of free radicals by exogenous administration of xanthine plus xanthine oxidase, cardiac contractility was significantly depressed leading to decreases in stroke volume, cardiac output, and blood pressure. Using identical procedures to evaluate contractility, we have demonstrated that the initial depression of myocardial contractility was not the causative factor for circulatory failure in the two models of shock.(ABSTRACT TRUNCATED AT 250 WORDS)