FFA-induced hepatic insulin resistance in vivo is mediated by PKCδ, NADPH oxidase, and oxidative stress.

Fat-induced hepatic insulin resistance plays a key role in the pathogenesis of type 2 diabetes in obese individuals. Although PKC and inflammatory pathways have been implicated in fat-induced hepatic insulin resistance, the sequence of events leading to impaired insulin signaling is unknown. We used Wistar rats to investigate whether PKCδ and oxidative stress play causal roles in this process and whether this occurs via IKKß- and JNK-dependent pathways. Rats received a 7-h infusion of Intralipid plus heparin (IH) to elevate circulating free fatty acids (FFA). During the last 2 h of the infusion, a hyperinsulinemic-euglycemic clamp with tracer was performed to assess hepatic and peripheral insulin sensitivity. An antioxidant, N-acetyl-L-cysteine (NAC), prevented IH-induced hepatic insulin resistance in parallel with prevention of decreased IκBα content, increased JNK phosphorylation (markers of IKKß and JNK activation, respectively), increased serine phosphorylation of IRS-1 and IRS-2, and impaired insulin signaling in the liver without affecting IH-induced hepatic PKCδ activation. Furthermore, an antisense oligonucleotide against PKCδ prevented IH-induced phosphorylation of p47(phox) (marker of NADPH oxidase activation) and hepatic insulin resistance. Apocynin, an NADPH oxidase inhibitor, prevented IH-induced hepatic and peripheral insulin resistance similarly to NAC. These results demonstrate that PKCδ, NADPH oxidase, and oxidative stress play a causal role in FFA-induced hepatic insulin resistance in vivo and suggest that the pathway of FFA-induced hepatic insulin resistance is FFA → PKCδ → NADPH oxidase and oxidative stress → IKKß/JNK → impaired hepatic insulin signaling.

Proliferative diabetic retinopathy: Role of bevacizumab in decreasing the occurrence of vitreous hemorrhage after panretinal photocoagulation.

PURPOSE: To investigate the beneficial effect of bevacizumab injection one week prior to panretinal photocoagulation (PRP) on the occurrence of vitreous hemorrhage (VH) following PRP in high-risk proliferative diabetic retinopathy (PDR). METHODS: This was a case-control pilot study conducted on two groups: an anti-VEGF treatment group, treated with bevacizumab injection one week prior to the first PRP session, and a control group of treatment-naive PDR patients who underwent PRP treatment and were not given an intravitreal bevacizumab injection, consecutively recruited. In both groups, a complete ophthalmological examination was conducted prior to PRP and at 4, 9, and 16 weeks following treatment. The primary endpoint studied was the occurrence of VH. RESULTS: The control group included 69 patients (mean age 63±12.3 years) with high-risk PDR who received PRP treatment only, and the anti-VEGF treatment group included 67 patients (mean age 63.13±10.3 years). None of the demographic variables or comorbidities showed any significant difference between the two groups. The number of PRP sessions was not significantly correlated to the occurrence of VH in either of the groups (P=0.167). Vitreous hemorrhage within 16 weeks following laser treatment occurred in 10 patients (14.5%) in the control group and in only 3 patients (4.5%) in the anti-VEGF group (P=0.047). CONCLUSION: Our case-control pilot study demonstrates that a bevacizumab injection preceding the initial PRP session might be beneficial in reducing the occurrence of VH in the first 16 weeks following PRP.

Methylotrophic bacteria: biochemical diversity and genetics.

Bacteria that are able to use methane as a sole carbon and energy source also carry out a broad range of biotransformations, some of which have industrial and environmental significance. Genetic studies on methylotrophs, including the use of recombinant DNA techniques, show promise for the isolation and cloning of genes coding for specific functions.

Dopamine D(3) receptor antagonists. 1. Synthesis and structure-activity relationships of 5,6-dimethoxy-N-alkyl- and N-alkylaryl-substituted 2-aminoindans.

5,6-Dimethoxy-2-(N-dipropyl)-aminoindan (3, PNU-99194A) was found to be a selective dopamine D(3) receptor antagonist with potential antipsychotic properties in animal models. To investigate the effects of nitrogen substitution on structure-activity relationships, a series of 5,6-dimethoxy-N-alkyl- and N-alkylaryl-substituted 2-aminoindans were synthesized and evaluated in vitro for binding affinity and metabolic stability. The results indicate that substitution at the amine nitrogen of the 2-aminoindans is fairly limited to the di-N-propyl group in order to achieve selective D(3) antagonists. Thus, combinations of various alkyl groups were generally inactive at the D(3) receptor. Although substitution with an N-alkylaryl or N-alkylheteroaryl group yields compounds with potent D(3) binding affinity, the D(2) affinity is also enhanced, resulting in a less than 4-fold preference for the D(3) receptor site, and no improvements in metabolic stability were noted. A large-scale synthesis of the D(3) antagonist 3 has been developed that has proven to be reproducible with few purification steps. The improvements include the use of 3,4-dimethoxybenzaldehyde as a low-cost starting material to provide the desired 5,6-dimethoxy-1-indanone 5c in good overall yield (65%) and the formation of a soluble silyl oxime 17 that was reduced efficiently with BH(3).Me(2)S. The resulting amino alcohol was alkylated and then deoxygenated using a Lewis acid and Et(3)SiH to give the desired product 3 in good overall yield of ( approximately 65%) from the indanone 5c.

Anthelmintic activity of dioxapyrrolomycin.

Dioxapyrrolomycin, pyrrolomycin C, pyrrolomycin D, and piericidin C2 produced by UC 11065 were evaluated as anthelmintics. Assays used to examine these compounds included effects on the free-living nematode Caenorhabditis elegans, ability to clear target nematodes (Haemonchus contortus and Trichostrongylus colubriformis) from jirds, and clearance of Haemonchus contortus from lambs. A crude extract of UC 11065 containing dioxapyrrolomycin, pyrrolomycin C, pyrrolomycin D, and piericidin C2 was active against C. elegans and against H. contortus in the jird. Purified and/or synthetic samples of dioxapyrrolomycin, pyrrolomycin C, pyrrolomycin D, and piericidin C2 were tested in the jird model; only dioxapyrrolomycin exhibited appreciable activity against H. contortus (greater than or equal to 90.9% clearance at 0.33 mg/jird), while none of the compounds showed appreciable activity against T. colubriformis. Dioxapyrrolomycin cleared 99.9% of H. contortus from lambs at 12.5 mg/kg. An in vitro migration study using susceptible and closantel-resistant H. contortus showed there is cross-resistance between dioxapyrrolomycin and closantel. Dioxapyrrolomycin appears to be a narrow-spectrum anthelmintic which works through a closantel-like mode-of-action.

Conductivity detection in capillary electrophoresis--a powerful tool in ion analysis.

Conductivity detection in CE has recently become available in a commercial CE instrument. The new conductivity cell is based on an end-capillary concept. The conductivity sensor and the detection end of the fused-silica capillary are permanently encapsulated in two individually modified coupling connectors (ConTip, ConCap [both from Orion Research, Boston, MA, U.S.A.]). This open-architecture cell permits interchangeability of sensors and capillaries, while maintaining a precisely defined detection volume between those two components when inserted into the detector cell block. The detector's performance is evaluated for sensitivity, linearity, and reproducibility using low-mobility electrolytes. Electropherograms comprising a variety of ionic class separations including inorganic and organic anions, organic surfactants, alkali metals, alkaline earths, transition metals, and organic amines are shown along with separations of actual samples.

The psychoanalytic treatment of a preschool boy with a gender identity disorder.

A three-year, nine-month-old boy began analysis by wishing he was a girl and pretending he was a superheroine. Over the course of almost five years, the cross-gender defense against fear of loss of the object, anal loss, and castration by the object reorganized in all libidinal phases through early latency. Developmental arrests seemed to occur during the anal rapprochement and oedipal phases that led to observable cross-gender strivings by two and a half years of age. The role of early childhood illness, narcissistic vulnerability, mother's childhood wish for a sister, the mother's adult wish for a daughter, a shared fantasy between mother and child, identification with the perceived power and beauty of mother and grandmother, pathological sibling rivalry that influenced identification with his sister, were demonstrated in his play during sessions. Interwoven in the background was the impact of an emotionally absent father, a dying grandfather, and an accident-prone uncle. This paternal matrix seemed to discourage budding masculinity and encourage feminine identifications. The analyst's approach and the child's responses to interpretation of the transference manifestations, cross-gender behavior, fantasies, and play are presented. Finally, the gradual resolution of the conflicted wish to be a girl was supplanted by the emergence of appropriate gender identification. A two-year followup appeared to confirm his postanalytic gender stance and continuing consolidation of stable gender development.

Proteins kinase Cɛ is required for non-small cell lung carcinoma growth and regulates the expression of apoptotic genes.

Protein kinase C (PKC)ɛ, a member of the novel PKC family, has key roles in mitogenesis and survival in normal and cancer cells. PKCɛ is frequently overexpressed in epithelial cancers, particularly in lung cancer. Using a short-hairpin RNA approach, here we established that PKCɛ is required for non-small cell lung carcinoma (NSCLC) growth in vitro as well as tumor growth when inoculated into athymic mice. Moreover, sustained delivery of a PKCɛ-selective inhibitor peptide, ɛV1-2, reduced xenograft growth in mice. Both RNA interference depletion and pharmacological inhibition of PKCɛ caused a marked elevation in the number of apoptotic cells in NSCLC tumors. PKCɛ-depleted NSCLC cells show elevated expression of pro-apoptotic proteins of the Bcl-2 family, caspase recruitment domain-containing proteins and tumor necrosis factor ligands/receptor superfamily members. Moreover, a Gene Set Enrichment Analysis revealed that a vast majority of the genes changed in PKCɛ-depleted cells were also deregulated in human NSCLC. Our results strongly suggest that PKCɛ is required for NSCLC cell survival and maintenance of NSCLC tumor growth. Therefore, PKCɛ may represent an attractive therapeutic target for NSCLC.

Effects of portal free fatty acid elevation on insulin clearance and hepatic glucose flux.

We tested the hypothesis that, due to greater hepatic free fatty acid (FFA) load, portal delivery of FFAs, as in visceral obesity, induces hyperinsulinemia and increases endogenous glucose production to a greater extent than peripheral FFA delivery. For 5 h, 10 microeq.kg(-1).min(-1) portal oleate (n = 6), equidose peripheral oleate (n = 5), or saline (n = 6) were given intravenously to conscious dogs infused with a combination of portal and peripheral insulin to enable calculation of hepatic insulin clearance during a pancreatic euglycemic clamp. Peripheral FFAs were similar with both oleate treatments and were threefold greater than in controls. Portal FFAs were 1.5- to 2-fold greater with portal than with peripheral oleate. Peripheral insulin concentrations were greatest with portal oleate, intermediate with peripheral oleate (P < 0.001 vs. portal oleate or controls), and lowest in controls, consistent with corresponding reductions in plasma insulin clearance and hepatic insulin clearance. Although endogenous glucose production did not differ between the two routes of oleate delivery, total glucose output (endogenous glucose production plus glucose cycling) was greater with portal than with peripheral oleate (P < 0.001) despite the higher insulin levels. In conclusion, during euglycemic clamps in dogs, the main effect of short-term elevation in portal FFA is to generate peripheral hyperinsulinemia. This may, in the long term, contribute to the metabolic and cardiovascular risk of visceral obesity.

Geriatrics: a specialty in search of specialists.

This paper explores the historical reasons why geriatrics has failed to become a popular specialty in America. Focusing upon the nineteenth and early twentieth centuries, it examines the medical theories and ideas that led to the creation of a specialty in the diseases of old age. According to Haber, these beliefs caused many would-be geriatricians to be extremely reluctant to devote themselves to the new field. While such physicians were often convinced that a separate practice for the old was both theoretically valid and necessary, they were far less sure of the ultimate usefulness of their work. The prevailing model of senescence portrayed old age as a progressive, incurable disease, and the elderly as the most difficult and trying of patients. Medically, as well as economically, geriatrics seemed to have little appeal. The author concludes that these beliefs still influence many physicians' conception of geriatrics; it remains a specialty in search of specialists.

Antioxidants attenuate endotoxin-gentamicin induced acute renal failure in rats.

The synergistic mechanism by which endotoxin enhances the nephrotoxic potential of gentamicin is unknown. In this study, we attempted to shed light on this mechanism by injecting rats with endotoxin plus gentamicin. Renal injury was assessed by measuring creatinine, inulin and PAH clearance, NADH levels and electrolyte reabsorption, for 24 hr following this injection. Gentamicin alone (20 mg/100 g) induced no renal injury, while endotoxin without gentamicin (0.075 mg/100 g) induced mild injury. However, endotoxin plus gentamicin resulted in acute renal failure. In an attempt to halt the progressive renal dysfunction, the antioxidants NAO (5 mg/100 g), Vitamin E (0.2 mg/100 g per day) and dimethylthiourea (DMTU-50 mg/100 g) were administered, or early endotoxin tolerance was induced before injecting the rats with endotoxin plus gentamicin. The reduction in renal function was markedly slower in rats administered with antioxidants compared with untreated rats. Similar results were obtained with endotoxin tolerance. These data suggest that NAO, vitamin E, DMTU and endotoxin tolerance are potentially beneficial in arresting progressive renal damage associated with endotoxin plus gentamicin.

Shear-induced assembly of lambda-phage DNA.

Recombinant DNA technology, which is based on the assembly of DNA fragments, forms the backbone of biological and biomedical research. Here we demonstrate that a uniform shear flow can induce and control the assembly of lambda-phage DNA molecules: increasing shear rates form integral DNA multimers of increasing molecular weight. Spontaneous assembly and grouping of end-blunted lambda-phage DNA molecules are negligible. It is suggested that shear-induced DNA assembly is caused by increasing the probability of contact between molecules and by stretching the molecules, which exposes the cohesive ends of the otherwise undeformed lambda-phage DNA molecules. We apply this principle to enhance the kinetics and extent of DNA concatenation in the presence of ligase. This novel approach to controlled DNA assembly could form the basis for improved approaches to gene-chip and recombinant DNA technologies and provide new insight into the rheology of associating polymers.