Coral thermal stress and bleaching enrich and restructure reef microbial communities via altered organic matter exudation

Coral bleaching is a well-documented and increasingly widespread phenomenon in reefs across the globe, yet there has been relatively little research on the implications for reef water column microbiology and biogeochemistry. A mesocosm heating experiment and bottle incubation compared how unbleached and bleached corals alter dissolved organic matter (DOM) exudation in response to thermal stress and subsequent effects on microbial growth and community structure in the water column. Thermal stress of healthy corals tripled DOM flux relative to ambient corals. DOM exudates from stressed corals (heated and/or previously bleached) were compositionally distinct from healthy corals and significantly increased growth of bacterioplankton, enriching copiotrophs and putative pathogens. Together these results demonstrate how the impacts of both short-term thermal stress and long-term bleaching may extend into the water column, with altered coral DOM exudation driving microbial feedbacks that influence how coral reefs respond to and recover from mass bleaching events.

Suboxic DOM is bioavailable to surface prokaryotes in a simulated overturn of an oxygen minimum zone, Devil's Hole, Bermuda

Oxygen minimum zones (OMZs) are expanding due to increased sea surface temperatures, subsequent increased oxygen demand through respiration, reduced oxygen solubility, and thermal stratification driven in part by anthropogenic climate change. Devil's Hole, Bermuda is a model ecosystem to study OMZ microbial biogeochemistry because the formation and subsequent overturn of the suboxic zone occur annually. During thermally driven stratification, suboxic conditions develop, with organic matter and nutrients accumulating at depth. In this study, the bioavailability of the accumulated dissolved organic carbon (DOC) and the microbial community response to reoxygenation of suboxic waters was assessed using a simulated overturn experiment. The surface inoculated prokaryotic community responded to the deep (formerly suboxic) 0.2 μm filtrate with cell densities increasing 2.5-fold over 6 days while removing 5 μmol L-1 of DOC. After 12 days, the surface community began to shift, and DOC quality became less diagenetically altered along with an increase in SAR202, a Chloroflexi that can degrade recalcitrant dissolved organic matter (DOM). Labile DOC production after 12 days coincided with an increase of Nitrosopumilales, a chemoautotrophic ammonia oxidizing archaea (AOA) that converts ammonia to nitrite based on the ammonia monooxygenase (amoA) gene copy number and nutrient data. In comparison, the inoculation of the deep anaerobic prokaryotic community into surface 0.2 μm filtrate demonstrated a die-off of 25.5% of the initial inoculum community followed by a 1.5-fold increase in cell densities over 6 days. Within 2 days, the prokaryotic community shifted from a Chlorobiales dominated assemblage to a surface-like heterotrophic community devoid of Chlorobiales. The DOM quality changed to less diagenetically altered material and coincided with an increase in the ribulose-1,5-bisphosphate carboxylase/oxygenase form I (cbbL) gene number followed by an influx of labile DOM. Upon reoxygenation, the deep DOM that accumulated under suboxic conditions is bioavailable to surface prokaryotes that utilize the accumulated DOC initially before switching to a community that can both produce labile DOM via chemoautotrophy and degrade the more recalcitrant DOM.

Bacterioplankton communities reveal horizontal and vertical influence of an Island Mass Effect

Coral reefs are highly productive ecosystems with distinct biogeochemistry and biology nestled within unproductive oligotrophic gyres. Coral reef islands have often been associated with a nearshore enhancement in phytoplankton, a phenomenon known as the Island Mass Effect (IME). Despite being documented more than 60 years ago, much remains unknown about the extent and drivers of IMEs. Here we utilized 16S rRNA gene metabarcoding as a biological tracer to elucidate horizontal and vertical influence of an IME around the islands of Mo'orea and Tahiti, French Polynesia. We show that those nearshore oceanic stations with elevated chlorophyll a included bacterioplankton found in high abundance in the reef environment, suggesting advection of reef water is the source of altered nearshore biogeochemistry. We also observed communities in the nearshore deep chlorophyll maximum (DCM) with enhanced abundances of upper euphotic bacterioplankton that correlated with intrusions of low-density, O₂ rich water, suggesting island influence extends into the DCM.

Distinguishing the molecular diversity, nutrient content, and energetic potential of exometabolomes produced by macroalgae and reef-building corals

Metabolites exuded by primary producers comprise a significant fraction of marine dissolved organic matter, a poorly characterized, heterogenous mixture that dictates microbial metabolism and biogeochemical cycling. We present a foundational untargeted molecular analysis of exudates released by coral reef primary producers using liquid chromatography-tandem mass spectrometry to examine compounds produced by two coral species and three types of algae (macroalgae, turfing microalgae, and crustose coralline algae [CCA]) from Mo'orea, French Polynesia. Of 10,568 distinct ion features recovered from reef and mesocosm waters, 1,667 were exuded by producers; the majority (86%) were organism specific, reflecting a clear divide between coral and algal exometabolomes. These data allowed us to examine two tenets of coral reef ecology at the molecular level. First, stoichiometric analyses show a significantly reduced nominal carbon oxidation state of algal exometabolites than coral exometabolites, illustrating one ecological mechanism by which algal phase shifts engender fundamental changes in the biogeochemistry of reef biomes. Second, coral and algal exometabolomes were differentially enriched in organic macronutrients, revealing a mechanism for reef nutrient-recycling. Coral exometabolomes were enriched in diverse sources of nitrogen and phosphorus, including tyrosine derivatives, oleoyl-taurines, and acyl carnitines. Exometabolites of CCA and turf algae were significantly enriched in nitrogen with distinct signals from polyketide macrolactams and alkaloids, respectively. Macroalgal exometabolomes were dominated by nonnitrogenous compounds, including diverse prenol lipids and steroids. This study provides molecular-level insights into biogeochemical cycling on coral reefs and illustrates how changing benthic cover on reefs influences reef water chemistry with implications for microbial metabolism.

Organic Matter Composition at Ocean Station Papa Affects Its Bioavailability, Bacterioplankton Growth Efficiency and the Responding Taxa

The bioavailability of organic matter (OM) to marine heterotrophic bacterioplankton is determined by both the chemical composition of OM and the microbial community composition. In the current study, changes in OM bioavailability were identified at Ocean Station Papa as part of the 2018 Export Processes in the Ocean from Remote Sensing (EXPORTS) field study. Removal rates of carbon (C) in controlled experiments were significantly correlated with the initial composition of total hydrolyzable amino acids, and C removal rates were high when the amino acid degradation index suggested a more labile composition. Carbon remineralization rates averaged 0.19 ± 0.08 μmol C L-1 d-1 over 6-10 days while bacterial growth efficiencies averaged 31 ± 7%. Amino acid composition and tandem mass spectrometry analysis of compound classes also revealed transformations to a more degraded OM composition during experiments. There was a log2-fold increase in the relative abundances of 16S rDNA-resolved bacterioplankton taxa in most experiments by members of the Methylophilaceae family (OM43 genus) and KI89A order. Additionally, when OM was more bioavailable, relative abundances increased by at least threefold for the classes Bacteroidetes (Flavobacteriaceae NS2b genus), Alphaproteobacteria (Rhodobacteraceae Sulfitobacter genus), and Gammaproteobacteria (Alteromonadales and Ectothiorhodospiraceae orders). Our data suggest that a diverse group of bacterioplankton was responsible for removing organic carbon and altering the OM composition to a more degraded state. Elevated community diversity, as inferred from the Shannon-Wiener H index, may have contributed to relatively high growth efficiencies by the bacterioplankton. The data presented here shed light on the interconnections between OM bioavailability and key bacterioplankton taxa for the degradation of marine OM.

Stable Isotope Probing Identifies Bacterioplankton Lineages Capable of Utilizing Dissolved Organic Matter Across a Range of Bioavailability

Bacterioplankton consume about half of the dissolved organic matter (DOM) produced by phytoplankton. DOM released from phytoplankton consists of a myriad of compounds that span a range of biological reactivity from labile to recalcitrant. Linking specific bacterioplankton lineages to the incorporation of DOM compounds into biomass is important to understand microbial niche partitioning. We conducted a series of DNA-stable isotope probing (SIP) experiments using ¹³C-labeled substrates of varying lability including amino acids, cyanobacteria lysate, and DOM from diatom and cyanobacteria isolates concentrated on solid phase extraction PPL columns (SPE-DOM). Amendments of substrates into Sargasso Sea bacterioplankton communities were conducted to explore microbial response and DNA-SIP was used to determine which lineages of Bacteria and Archaea were responsible for uptake and incorporation. Greater increases in bacterioplankton abundance and DOC removal were observed in incubations amended with cyanobacteria-derived lysate and amino acids compared to the SPE-DOM, suggesting that the latter retained proportionally more recalcitrant DOM compounds. DOM across a range of bioavailability was utilized by diverse prokaryotic taxa with copiotrophs becoming the most abundant ¹³C-incorporating taxa in the amino acid treatment and oligotrophs becoming the most abundant ¹³C-incorporating taxa in SPE-DOM treatments. The lineages that responded to SPE-DOM amendments were also prevalent in the mesopelagic of the Sargasso Sea, suggesting that PPL extraction of phytoplankton-derived DOM isolates compounds of ecological relevance to oligotrophic heterotrophic bacterioplankton. Our study indicates that DOM quality is an important factor controlling the diversity of the microbial community response, providing insights into the roles of different bacterioplankton in resource exploitation and efficiency of marine carbon cycling.

Modification of growth related enzymatic pathways and apparent loss of tumorigenicity of a ras-transformed bovine endothelial cell line by treatment with 5-iodo-6-amino-1,2-benzopyrone (INH2BP)

Bovine aortic endothelial cells were converted to a highly tumorigenic cell line by transfection with Ha-ras and stimulation with thrombin. Sustained pretreatment with a non-cytotoxic concentration (600 mu M) of 5-iodo-6-amino-1,2-benzopyrone (INH2BP), a lipophilic ligand of poly(ADP-ribose) polymerase, abrogated in vivo tumorigenicity, of 10(5) cells per inoculum an effect which developed progressively during 2 to 6 weeks of drug treatment. The initial action of the drug was cytostasis, consisting of an arrest in prophase, extreme cell enlargement consistent with cytoplasmic hypertrophy, as seen by EM, and dramatic morphologic changes. Although neither DNA, RNA or protein syntheses are directly affected by INH2BP, apparently newly synthesized cellular DNA is degraded by endonucleases, which are upregulated by the inhibition of their poly-ADP-ribosylation. The drug treated cells exhibited greatly increased respiration and aerobic glycolysis, due to an augmentation of,glycolytic and respiratory enzymes in enlarged cells. These responses to the drug were reversible in cell cultures following drug removal, within 5-10 days drug exposure but the progressive loss of tumorigenicity in nude mice that developed after 3-6 weeks of drug exposure of cells, prior to inoculation to nude mice, was not reversible in vivo. Drug treatment produced a sustained 70-80% inhibition of pADPRT in intact cells at 600 mu M extracellular concentration of INH2BP. The prerequisite for the abrogation of tumorigenicity was the maintenance of pADPRT inhibition. The arrest of cell multiplication and a large decrease of Topo I, especially of Topo II and MAP kinase activities occurred without loss of enzyme protein as assayed in cell extracts of drug-treated cells. However INH2BP had no direct effect on these enzymes. Drug treatment down-regulated DNA-methyltransferase, PKC, ODC proteins, diminished cyclin A protein, but the hypophosphorylated form of Rb protein was significantly augmented. None of the enzymatic components of signal pathways so far studied, were directly affected by INH2BP. The inhibition of pADPRT by INH2BP coincided with an induction or activation of alkaline phosphatase and leucyl and glutamyl peptidase. The pADPRT content or the expression of pADPRT gene were not influenced by drug treatment, but the expression of ras gene was completely absent in nontumorigenic drug-treated cells, without a loss of ras gene from genomic DNA. Telomerase activity was not directly influenced by INH2BP treatment when assayed in diluted cell extracts, but the addition of homogeneous pADPRT to cell extracts, to approach physiological concentration of this protein in the cell, inhibited telomerase activity by binding of the polymer-free pADPRT to telomer templates. We conclude that inhibition of pADPRT indirectly down-regulates growth stimulatory signal pathways and sustains growth-arrested cells in culture at a pre-apoptotic threshold which explains the absence of tumorigenicity in vivo.

Plasmapheresis treatment of antibody-mediated rejection in an A2 donor to O pediatric liver transplant recipient

It is safe to transplant kidneys from blood group A2 donors into O recipients if the latter have low titers of anti-A antibodies. However, in liver transplantation, O and B recipients of A2 donor livers are not routinely screened for anti-blood group antibodies because of the immuno-absorptive capacity of the liver and the low incidence of antibody-mediated rejection. Herein, we report a rare case of combined cell and antibody-mediated rejection in a pediatric blood group O recipient of an A2 donor liver, and rescue of the allograft using PP and IVIG.

Novel ghrelin analogs with improved affinity for the GH secretagogue receptor stimulate GH and prolactin release from human pituitary cells

OBJECTIVE

Ghrelin, a recently identified 28-amino acid peptide is a potent GH secretagogue (GHS) produced predominantly by the stomach. Ghrelin stimulates GH secretion through binding to the GHS receptor in the hypothalamus and pituitary. In addition to the GH-releasing action, ghrelin has been found to be a powerful orexigenic factor. To assess the direct in vitro effects of ghrelin on human pituitary hormone secretion we have produced a panel of novel ghrelin analogs (molecular weight, 3323-3384; human native ghrelin, 3371) with enhanced affinity for the human GHS receptor (IC(50) 0.38-1.09 nM; human ghrelin, 1.2-2.2 nM).

METHODS

The peptidic analogs were tested for their effect on GH secretion using dispersed human fetal pituitaries (21 to 23 weeks of gestation) and cultured GH- and prolactin (PRL)-secreting adenomas. The expression of the GHS receptor in normal (fetal and adult) human pituitary tissues, GH- and PRL-cell adenomas was established using RT-PCR.

RESULTS

The effects of ghrelin, its analogs and GH-releasing hormone (GHRH) alone or in combination on GH and PRL secretion were compared at various concentrations. The ghrelin analogs stimulated GH release by 35-60% from human fetal pituitary cells (1-10 nM; P<0.05) and by 50-75% from cultured pituitary adenomas (10 nM; P<0.05). This releasing effect was dose-dependent, achieving maximal stimulation with analog concentrations at 100 nM. Human ghrelin was less potent as compared with its analogs in stimulating human GH, in keeping with the improved binding affinity of the analogs for the GHS-1a receptor. The ghrelin analogs and GHRH had comparable effects on GH secretion from both normal and adenomatous cells, and in combination produced an additive stimulatory effect on GH (150%; P<0.0001). In contrast, ghrelin and its analogs induced a comparable increase in PRL release ranging between 25 and 40% (P<0.05) from fetal cells and 30 and 70% (P<0.001) from cultured PRL-cell and mixed GH-PRL adenomas.

CONCLUSIONS

Our results have demonstrated for the first time that ghrelin analogs with enhanced affinity for the GHS receptor are potent stimulators of GH secretion from human pituitary cells, and thus may possess potential clinical therapeutic benefits.

Effect of intensive glycemic control on fibrinogen, lipids, and lipoproteins: Veterans Affairs Cooperative Study in Type II Diabetes Mellitus

BACKGROUND

The Veterans Affairs Cooperative Study in Type II Diabetes Mellitus prospectively studied insulin-treated patients with type 2 (non-insulin-dependent) diabetes mellitus, achieving 2.1% glycosylated hemoglobin separation between intensive- and standard-treatment arms (P<.001) for 2 years.

OBJECTIVE

To assess the effect of intensive therapy on serum fibrinogen and lipid levels, compared with standard treatment.

METHODS

One hundred fifty-three male subjects with type 2 diabetes mellitus and who required insulin treatment were recruited from 5 Veterans Affairs medical centers. The subjects were divided into intensive- and standard-treatment arms for a randomized prospective study. Dyslipidemia was managed identically in both arms (diet, drugs). Fibrinogen levels and lipid fractions were measured in the full cohort. Lipid fractions are separately reported in patients not treated with hypolipidemic agents.

RESULTS

There were no baseline differences between arms. Fibrinogen levels rose in the intensive-treatment arm at 1 year (from 3.34+/-0.12 to 3.75+/-0.15 g/L; P<.001) but returned to baseline at 2 years (3.47+/-0.12 g/L). There was no change in the standard-treatment arm. Triglyceride levels decreased in the intensive-treatment arm from 2.25+/-0.27 to 1.54+/-0.14 mmol/L (199+/-24 to 136+/-12 mg/ dL) at 1 year (P = .004) and to 1.74+/-0.18 mmol/L (154+/-16 mg/dL) at 2 years (P = .03); there was no change in the standard-treatment arm. Cholesterol levels decreased in the intensive-treatment arm at 1 year from 5.4+/-0.21 to 4.99+/-0.13 mmol/L (207+/-8 to 193+/-5 mg/dL) (P = .02); there was no change in the standard-treatment arm. Levels of low- and high-density lipoprotein cholesterol decreased in the standard-treatment arm only by 2 years, from 3.44+/-0.13 to 3.16+/-0.10 mmol/L (133+/-5 to 122+/-4 mg/ dL) (P =.02) and from 1.10+/-0.03 to 1.00+/-0.03 mmol/L (42+/-1 to 38+/-1 mg/dL) (P<.001) for low-density and high-density lipoprotein cholesterol, respectively. Levels of apolipoprotein B decreased in both treatment arms (P<.001), and apolipoprotein A1 levels decreased in the standard-treatment arm (P<.01). Lipoprotein (a) levels did not change in either treatment arm. Lipid results were essentially identical whether examined in the full cohort or excluding those patients receiving hypolipidemic agents.

CONCLUSIONS

Intensive insulin therapy led to a potentially beneficial reduction in serum triglyceride levels and preservation of high-density lipoprotein cholesterol and apolipoprotein A1 levels. However, it caused transient elevation in plasma fibrinogen levels, a possible thrombogenic effect.

Role of orlistat in the treatment of obese patients with type 2 diabetes. A 1-year randomized double-blind study

OBJECTIVE

Obesity is an important risk factor for type 2 diabetes. Weight loss in patients with type 2 diabetes is associated with improved glycemic control and reduced cardiovascular disease risk factors, but weight loss is notably difficult to achieve and sustain with caloric restriction and exercise. The purpose of this study was to assess the impact of treatment with orlistat, a pancreatic lipase inhibitor, on weight loss, glycemic control, and serum lipid levels in obese patients with type 2 diabetes on sulfonylurea medications.

RESEARCH DESIGN AND METHODS

In a multicenter 57-week randomized double-blind placebo-controlled study, 120 mg orlistat or placebo was administered orally three times a day with a mildly hypocaloric diet to 391 obese men and women with type 2 diabetes who were aged > 18 years, had a BMI of 28-40 kg/m2, and were clinically stable on oral sulfonylureas. Changes in body weight, glycemic control, lipid levels, and drug tolerability were measured.

RESULTS

After 1 year of treatment, the orlistat group lost 6.2 +/- 0.45% (mean +/- SEM) of initial body weight vs. 4.3 +/- 0.49% in the placebo group (P < 0.001). Twice as many patients receiving orlistat (49 vs. 23%) lost > or = 5% of initial body weight (P < 0.001). Orlistat treatment plus diet compared with placebo plus diet was associated with significant improvement in glycemic control, as reflected in decreases in HbA1c (P < 0.001) and fasting plasma glucose (P < 0.001) and in dosage reductions of oral sulfonylurea medication (P < 0.01). Orlistat therapy also resulted in significantly greater improvements than placebo in several lipid parameters, namely, greater reductions in total cholesterol, (P < 0.001), LDL cholesterol (P < 0.001), triglycerides (P < 0.05), apolipoprotein B (P < 0.001), and the LDL-to-HDL cholesterol ratio (P < 0.001). Mild to moderate and transient gastrointestinal events were reported with orlistat therapy, although their association with study withdrawal was low. Fat-soluble vitamin levels generally remained within the reference range, and vitamin supplementation was required in only a few patients.

CONCLUSIONS

Orlistat is an effective treatment modality in obese patients with type 2 diabetes with respect to clinically meaningful weight loss and maintenance of weight loss, improved glycemic control, and improved lipid profile.

Inhibition of the GTP-dependent polymerization of tubulin by methyl-3,5-diiodo-4-(4'-methoxyphenoxy) benzoate (DIME)

The hormonally inactive thyroid hormone analog methyl-3,5-diiodo-4-(4'-methoxyphenoxy) benzoate (DIME) at 1-5 mu M concentrations inhibits the GTP-dependent polymerization of MTP as determined by an optical test. This inhibition is critically dependent on the concentration of GTP. The quantitative correlation between the concentrations of DIME and GTP, under conditions of a linear rat of MTP polymerization, follows Michaelis-Menten kinetics and the inhibition portrays a 'mixed' type, where k(m) for GTP and V-max are altered simultaneously. Chemical analogs of DIME inhibit MTP polymerization parallel to their antitumorigenic action in vivo. The MTP site is one of the early cellular response sites of DIME.

Effect of relationship length on the experience, expression, and perceived appropriateness of jealousy

The effect of relationship length on the perceived appropriateness and intensity of the experience and expression of romantic jealousy among American students was explored. Linear increases in perceived appropriateness and intensity of jealousy were predicted. The results largely supported the hypotheses, with jealousy experience, expression, and perceived appropriateness of jealousy expression increasing over time. However, the perceived appropriateness of jealousy experience did not vary significantly across relationship lengths. Ethnic differences in perceptions of appropriateness of jealousy experience and expression were also found.

Evaluations of retinopathy in the VA Cooperative Study on Glycemic Control and Complications in Type II Diabetes (VA CSDM). A feasibility study

OBJECTIVE

The main goal of the study of 153 male veterans was to determine whether a statistically and clinically significant difference in HbA1c could be achieved between a standard therapy and an intensively treated group of patients with type II diabetes. A second major goal was to assess the feasibility of collecting reliable high-quality endpoint data, including microvascular and macrovascular events. Retinopathy was defined as a key microvascular endpoint.

RESEARCH DESIGN AND METHODS

This was a randomized prospective trial of 153 men between the ages of 40 and 69 years, with type II diabetes for 15 years or less. Of the patients, 78 were assigned to the standard therapy arm and 75 to the intensive therapy arm. The goal of standard therapy was good general medical care and well-being and avoiding excessive hyperglycemia, glycosuria, ketonuria, or hypoglycemia. This was generally accomplished with one shot of insulin per day. The goal of intensive therapy was to obtain an HbA1c within two standard deviations of the mean of nondiabetic subjects (4.0-6.1%). This was obtained by a four-step management technique, with patients moving to the next step only if operational goals were not met. The steps were as follows: step 1: evening intermediate or long-acting insulin only; step 2: evening insulin with daytime glipizide; step 3: insulin, twice a day, no glipizide; and step 4: more than two injections of insulin, no glipizide. Retinopathy was assessed at baseline, 12, and 24 months by seven-field stereo fundus photography done at each of the five participating VA medical centers and read at the Central Reading Center at the Department of Ophthalmology, University of Wisconsin Medical School, Madison. Visual acuity was determined by ophthalmologists at each of the participating hospitals.

RESULTS

After the 6th month of the 24-month study, an average HbA1c of approximately 7.1% in the intensively treated group was sustained for the full study and was significantly lower than that seen in the standard group (9.2%, P < 0.001). Compliance in obtaining fundus photographs was excellent. Near normalization of glycemia did not cause transient worsening of retinal morphology nor did it prevent the onset or delay the progression of retinopathy. There was no effect on visual acuity.

CONCLUSIONS

1) A glycemic control intervention study in people with type II diabetes is feasible and safe; 2) intensive control did not cause transient deterioration of retinopathy; and 3) although no improvement was seen in retinopathy, the follow-up was 24 months, an interval shorter than the 3 years or more of intensive therapy before improvement is seen in type 1 diabetic studies. This does not rule out the possibility that longer periods of intensive therapy would have improved retinopathy. A full-scale intervention trial in type II diabetes is needed to resolve this issue.

Comparison of Texas Liquid Sampler with Missouri Bottle for Sampling Liquid Fertilizers: Collaborative Study

Six laboratories participated in a collaborative study designed to qualify the Texas liquid sampling tube as a device for sampling liquid fertilizers. The Texas sampler is a polyethylene tube with a stainless steel check valve on one end. The tube, which is threaded so that it can be expanded in length, enables acquisition of a uniform profile across a liquid sample. The 6 collaborators sampled 33 loads of fertilizer, 8 of which were slurries, using both the Texas tube and the Missouri bottle (AOAC 969.01). The resulting subsamples were analyzed for total nitrogen, available phosphorus, and soluble potash. Analysis of the data showed no significant (p &lt; 0.05) difference in results. This sampling procedure, using the Texas liquid sampler, was adopted first action by AOAC International as a suitable means of sampling liquid fertilizers.

Glycemic control and complications in type II diabetes. Design of a feasibility trial. VA CS Group (CSDM)

OBJECTIVE

To determine, after 1 yr of follow-up in type II diabetes patients, whether a statistically and clinically significant difference can be achieved in HbA1c between a standard therapy group and an intensively treated group, while maintaining HbA1c levels in both groups within ranges acceptable in regular community practice. Secondary objectives include assessment of patient adherence to protocol, side effects, and accuracy of data collection.

RESEARCH DESIGN AND METHODS

This is a prospective, randomized, controlled VA CS conducted with 151 patients at five VAMCs. Patients are males, age 40-69 yr, treated at entry with a maximum dose of sulfonylurea or with insulin, exhibiting an HbA1c level > 3 SDs above the normal mean (5.05 + 3 x 0.50 = > 6.55%). Standard control is achieved with insulin and intensive control with a step-up regimen including insulin alone or insulin/glipizide combinations. Education and management of cardiovascular risk factors are handled similarly in both groups. Primary macrovascular end points are nonfatal myocardial infarction, congestive heart failure, stroke, amputation, and cardiovascular death. Primary microvascular end points are appearance and progression of retinopathy, documented by centrally read seven-field-stereo fundus photographs. Other measured indicators include resting and ambulatory ECGs, ventricular function (MUGA scan), serum lipid and apolipoprotein levels, plasma fibrinogen, nonsymptomatic peripheral vasculopathy, neuroautonomic status by heart-beat variation on Valsalva maneuver, and microalbuminuria.

CONCLUSIONS

This study may be the basis for a long-term trial, involving 1400 patients, to assess the long-term effects of metabolic control on macro- and microvascular end points.

Experience and expression of jealousy: comparison between friends and romantics

A survey was administered to assess the differences between friends and romantics regarding the experience and expression of jealousy. The first hypothesis predicted that the perceived appropriateness of the expression of jealousy would be greater in romantic relationships than in friendships. Therefore, the second hypothesis predicted that the expression of jealousy would be greater in romantic relationships than in friendships. Third, it was expected that the intensity of jealousy would be a stronger predictor of expression for romantics than for friends. The first two hypotheses were confirmed; however, the last hypothesis received only tenuous support. While t tests yielded no significant differences on the intensity of the experience of jealousy between friends and romantics, the difference on expression is explained in terms of social or normative influences.

Undiagnosed abuse in children younger than 3 years with femoral fracture

We retrospectively evaluated 138 children younger than 3 years with femoral fractures who presented to the emergency departments of three major Michigan hospitals between 1979 and 1983. Patients were classified into one of the following four subgroups based on presenting history: accident (22%), bone pathology (8%), abuse (10%), and uncertain origin (60%). Distribution of common fracture types among the four subgroups was similar. Of the uncertain group, 22 cases of abuse were identified during admission and 7 additional cases were found at a later date. The total number of femoral fractures secondary to abuse was 43 (31%) of 138. Children younger than 3 years presenting with a femoral fracture should evoke a high suspicion for abuse.

A multicentre trial of the aldose-reductase inhibitor, tolrestat, in patients with symptomatic diabetic neuropathy

The effects of the aldose-reductase inhibitor, tolrestat, on chronic symptomatic diabetic sensorimotor neuropathy were studied during a placebo-controlled, randomised, 52-week multicentre trial. Of the four tolrestat doses investigated, only the highest dose group, 200 mg once daily, showed subjective and objective benefit over baseline and placebo, and further analyses are confined to this group (n = 112) and placebo (n = 107). Painful and paraesthetic symptoms were analysed separately: improvement in paraesthetic symptoms were seen at one year (p = 0.04), though painful symptoms improved on both placebo and active therapies. Significant improvement in both tibial and peroneal motor nerve conduction velocities were seen at 52 weeks. Tolrestat 200 mg once daily was significantly better than placebo in producing concordant improvements in both motor nerve conduction velocities and paraesthetic symptom scores at 24 weeks (p = 0.01), 42 weeks (p = 0.01) and 52 weeks (p = 0.02). Long-term benefit [concordant improvement at 24 weeks maintained until 52 weeks] was seen in 28% of treated patients compared to 5% on placebo (p = 0.001). It is concluded that some sustained improvement in symptomatic diabetic neuropathy may be obtained following aldose-reductase inhibition with tolrestat 200 mg once daily.

Photolytic inhibition and labeling of proteins with aryl diazonium compounds

In the course of preparing aryl azide derivatives for use as photoprobes, we have observed significant light sensitivity in the precursor aryl diazonium compounds. The photosensitive properties of this class of compounds are of interest since they will seek out cationic binding sites in biological targets, and can be employed to inhibit complementary targets at acid pH. The relationship between photolytic change in the structure of diazonium compounds and the corresponding change in function of a biological target are presented. Experiments are described in which the dark and light sensitive properties of a model diazonium compound, diazobenzene sulfonate (DBS), were determined. The ultraviolet spectra were used to evaluate the dark stability and light sensitivity of DBS. Chymotrypsin and trypsin served as functioning targets for further evaluation of the photochemical properties. Both enzymes are stable to the probe in the dark at acid pH. A rapid loss of enzyme activity was observed following flash photolysis of DBS-enzyme solutions. Photolytic incorporation of radioactive DBS into chymotrypsin was observed. Aryl diazonium salts can be employed to probe the availability of complementary sites in biological targets at different acid pH values.