Regulation of different proteolytic pathways in skeletal muscle in fasting and diabetes mellitus

1. Proteins in eukaryotic cells are continually degraded and replaced under precise control mechanisms. Although this continual proteolysis may seem wasteful, it serves several important functions: cells selectively degrade proteins with abnormal sequences or conformations, the accumulation of which could be harmful; the rapid degradation of regulatory peptides and enzymes is essential for the control of metabolic pathways and the cell cycle; and the breakdown of proteins in starvation provides amino acids for gluconeogenesis and energy metabolism. 2. Protein breakdown in eukaryotic cells occurs through distinct pathways: A) lysosomal (involves cathepsins B, H, L, etc.); B) Ca(2+)-dependent (involves Ca(2+)-dependent proteases calpains I and II); C) ATP-dependent, that require or not ubiquitin (comprises at least two large cytosolic proteases, UCDEN and proteasome), and D) ATP-independent (it is not known which proteases are involved in this degradative system). Despite recent dramatic progress, the relative contributions of these pathways to the accelerated proteolysis occurring in normal and pathological states is still largely unknown. 3. In order to identify the cellular mechanisms of skeletal muscle atrophy during fasting and diabetes mellitus, we have studied protein turnover in soleus and EDL muscles from control and fasted (for 24 h) or diabetic rats (1, 3, 5 and 10 days after streptozotocin injection). 4. The increase in muscle proteolysis during fasting seems to be attributable to an enhancement of the energy-requiring process. An increase in the ATP-dependent proteolytic pathway was evident 1 day after food restriction and probably accounted for all of the increased proteolysis demonstrated in the EDL muscles. In parallel with the alterations in the ATP-dependent process, an increase in the ubiquitin-mRNA and proteasome subunit-mRNA was detected. 5. In the acute phase of diabetes (1-3 days) there was an activation of Ca(2+)-dependent (soleus and EDL) and ATP-dependent (EDL) pathways. However, after 5 and 10 days of diabetes the activity of these two pathways fell to values even below control ones. No changes in the lysosomal proteolytic system were observed during diabetes. 6. Although appreciable progress has been made in this research, a large number of important questions remain to be answered, and some of them are discussed in the present paper.

Incidence of translocation in Venezuelan Creole bulls

The Venezuelan Creole breed cattle is a Bos taurus well adapted to tropical conditions; however, it has demonstrated a low fertility rate. Recently, improvement in animal production by selection based on chromosomal analysis has allowed for the erradication of abnormalities involved in fertility problems, especially that of the 1 29 translocation. In the present work chromosomal analyses were carried out on 60 Creole bulls. Heparinized peripheral blood cells were cultured rendering metaphase spreads and subsequently stained by G- and C-banding techniques. The 1 29 translocation was observed in 13 of the 60 bulls. The occurrence of this translocation in Creole cattle is discussed.

Comparison of the course to end-stage renal disease of type 1 (insulin-dependent) and type 2 (non-insulin-dependent) diabetic nephropathy

Is the course leading to diabetic end-stage renal disease similar for Type 1 (insulin-dependent) and Type 2 (non-insulin-dependent) diabetes mellitus? We identified all diabetic end-stage renal disease patients starting renal replacement therapy from 1989 to 1991 in two urban counties in Texas. Three ethnic/racial groups were enrolled: Mexican Americans, non-Hispanic Whites, African Americans. Patients were interviewed and their medical records, both inpatient and out-patient, were abstracted for relevant diagnostic and therapeutic information. We attempted to obtain records as far back as the onset of diabetes or hypertension and from all physicians who had cared for the patient. An historical algorithm was used to determine diabetic type. Of the patients enrolled, 91 were Type 1 and 438 were Type 2 diabetic patients. Type 1 diabetic patients had higher mean glucose levels in the first 10 years of diabetes (16.3 vs 11.4 mmol/l) but lower systolic blood pressures (148 vs 157 mmHg). The duration of diabetes prior to end-stage renal disease was longer for Type 1 than Type 2 patients (22 vs 17 years). Type 1 diabetic patients were more likely to have other microvascular complications (retinopathy, neuropathy, gastroparesis), less likely to have coronary disease (myocardial infarction and congestive heart failure), and had similar rates of stroke and vascular surgery procedures (carotid endarterectomy, coronary artery bypass surgery, aortofemoral bypass). Type 1 and Type 2 diabetic patients were just as likely to have a first degree relative with hypertension (60.5 vs 65.5%).(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatitis C viral RNA amplification by the polymerase chain reaction allows detection of false positive HCV ELISAs among patients with non-A, non-B hepatitis

Serum from patients which tested positive for hepatitis C virus (HCV) by Enzyme Linked Immunosorbent Assay (ELISA) were analyzed for the presence of HCV RNA by nested Polymerase Chain Reaction (PCR) and for anti-HCV antibodies by Recombinant Immunoblot Assay (RIBA II). Total RNA was extracted from whole blood by a new procedure and subjected to reverse transcription of HCV RNA employing primers to the conserved 5' non-coding region of the HCV genome. PCR performed on these samples uncovered several false positive ELISAs. Reciprocal confirmation between PCR and RIBA II results was observed. These results substantiate this variation of the HCV PCR assay as a reliable alternative for routine confirmation of HCV serological tests.

Epstein-Barr virus and childhood Hodgkin's disease in Honduras and the United States

In industrialized populations, Hodgkin's disease (HD) has an initial peak in young adulthood, whereas in economically developing populations the initial peak occurs in childhood. This pattern resembles that of infection with poliovirus and suggests an infectious cofactor in the etiology. Serologic studies have linked Epstein-Barr virus (EBV) to young adult and adult HD, and viral nucleic acids and antigens have been detected in a subset of Hodgkin's tumor specimens. To investigate the association of childhood HD with EBV we studied tumor specimens from 11 children treated in Honduras and 25 children treated in the United States using in situ hybridization and antigen detection techniques. Among the patients from Honduras, tumor specimens from all cases were EBV positive. Among the patients from the United States, tumor specimens from six of seven patients with mixed cellularity histology, 2 of 15 with nodular sclerosis histology, and neither of two patients with lymphocyte-predominant histologies were EBV positive. These findings support the hypothesis that EBV contributes to the pathogenesis of HD in children, particularly in mixed cellularity HD, and raises the possibility that there are important geographic, racial, or ethnic factors in the EBV association with HD.

Electromyographic feedback in the treatment of bilateral facial paralysis: a case study

Electromyographic feedback in the treatment of facial paralysis has been shown to be a useful alternative to surgical procedures. In this paper we report on the partial recovery of a 7-year-old patient with congenital bilateral facial paralysis (Moebius syndrome) that had been considered untreatable by medical specialists. Biofeedback of electromyographic activity was provided together with specific instructions, social reinforcement, and exercises that the patient carried out at home. The rehabilitation training lasted 1 year, during which there was a substantial increase in the electromyographic activity of the muscles on both sides of the face. A follow-up after 1 year of discontinuing the treatment showed that the muscle activity had been maintained and that there was a marked improvement in the patient's mood and facial expression.

[Effect of glucose and lactose on the utilization of citrate by Lactobacillus casei subsp. rhamnosus ATCC 7469]

The utilization of citrate by Lactobacillus casei subsp. rhamnosus ATCC 7469 in a complex medium containing glucose, lactose or citrate was investigated, as an approach to the question of the transport of this acid and the possible relationship with the production of flavour compounds (diacetyl and acetoin). This lactobacillus uses citrate as an energy source in the absence of carbohydrates. External pH and growth increases when citrate is added to complex medium. The presence of citrate does not affect glucose uptake. L. casei ATCC 7469 possibly uses a transport system for citrate utilization, and citrate uptake seems to be under glucose or lactose control. Lactose only inhibits the entrance of citrate at high concentration while the utilization of this acid was negatively regulated by low glucose concentration.

Synthesis and biological screening of aminothiadiazine dioxides related to trimethoprim

New derivatives of 3-amino-1,2,6-thiadiazine 1,1-dioxide have been synthesized and their antibacterial, antifungal and DHFR inhibitory activities evaluated. Their chemical structures have been established by means of analytical and NMR spectroscopic data. Among the compounds studied, the 4,4-dibromo derivative 11 showed fungistatic activity against C. albicans.

Molecular modeling studies on the urease active site and the enzyme-catalyzed urea hydrolysis

These studies are an attempt to gain better insight into the pharmacophore requirements of urease. On the basis of published information on this enzyme (EXAFS, amino acid sequence, essential groups at the active site) a hypothetical nickel-tripeptide complex, as preliminary substitute for the urease active site was modeled using computer-aided molecular modeling techniques. The results suggest two alternative docking modes of urea and reaction intermediates, corresponding to two different reaction mechanisms. Both binding modes are compatible with the docking of known potent inhibitors such as selected hydroxamic acids and phosphorodiamides. The results can be used to help in the design of new potential inhibitors of urease.

[Acute kidney insufficiency of obstetric origin. Experience at the Santo Tomas Hospital (1966-1981)]

The authors review 24 cases of acute renal failure of obstetric etiology occurred in Hospital Santo Tomás, which represents a frequency of 1.375/10,000, with a bimodal distribution and the main causes were toxemia of pregnancy and sepsis. All cases were of the oliguric type and a kidney biopsy was performed in 17 cases, revealing an acute tubular necrosis in 16 and a diffuse cortical necrosis in the other case. Two patients (8.3%) died and one did not received nephrology treatment as the other 23 patients. The fetal mortality was 37.5% and the Apgar was good in 2, fair in one and bad in 2. A 50% of the complications were infections and nine patients tolerated different surgical procedures after the installation of the acute renal failure. The follow-up of 12 patients shows no evidence of renal failure.

Cyclic adenosine monophosphate as a second messenger in horizontal cell uncoupling in the teleost retina

The reduction in the receptive field of horizontal cells of the teleost Eugerres plumieri observed upon dopamine (DA) superfusion is thought to be due to cell uncoupling. The possible mechanisms by which activation of DA receptors modify the electric coupling between horizontal cells were studied in the present work. It was found that the effect of DA in different preparations is mediated by a modification of intracellular concentration of cAMP and H+. The effects of intracellular injection of cAMP and H+ were studied in retinal horizontal cells of the teleost E. plumieri. A triple microelectrode was used to inject the ion iontophoretically, to pass current pulses, and to record voltages from the same cell, while a fourth microelectrode was used to record voltages from a neighboring cell in the same retinal layer. Responses evoked by light spots and annuli were evaluated simultaneously. Coupling ratios between neighboring horizontal cells ranged from 0.22 to 0.45. The intercellular resistance (Rc), 0.5-3.5 x 10(6) ohms, and that of the remaining cell membrane resistance (Rm), 2.5-18 x 10(6) ohms, were calculated by means of a passive electrical model that has a hexagonal array. The microinjection of H+ with injection current from +5 to +30 nA for 40 to 100 sec led to temporary and reversible light response reduction. The coupling ratio between two impaled cells was reduced by about 30%, and intercellular resistance (Rc) increment was 320% while cell membrane resistance (Rm) did not change consistently. There was also a temporary and reversible Rm reduction (70-85%) and an Rc increment of 170-330% when cyclic adenosine monophosphate was iontophoretically injected with current from -30 to -40 nA for 50 to 170 sec. The coupling ratio between two impaled cells was reduced by about 40%, and light responses recorded from the injected cell showed a reduction in amplitude with the same time course as that of the resistive changes. The injection of Lucifer yellow into a horizontal cell under normal conditions always results in pronounced fluorescence for more distant cells; however, under constant injection of H+ or cAMP only the injected cell is fluorescent, which provides direct evidence of the reduction in the effectiveness of coupling between horizontal cells. The observed effects of intracellular H+ or cAMP injection correspond to the resistive changes in Rc and coupling ratio that occur in the horizontal cell network upon superfusion with a dopamine (DA) solution.

[Prostitutes of the east sector of Santiago: characteristics and pathology of sexual transmission]

We studied the frequency of venereal disease in 329 prostitutes working at massage parlours in Santiago. The mean age was 24 years and half of them had high school or university studies. In spite of frequent sexual contacts averaging 2.8 per day, the prevalence of significant venereal disease was not high in this group. Notably, AIDS infection was not detected. Vaginitis due to Trichomonas or Candida infection was the commonest problem and this was half as frequent among gum preservative users. Marital condition, age, obstetrical history and other variables were not related to genital infection.

Interleukin-1, endotoxin or tumor necrosis factor/cachectin enhance the level of plasminogen activator inhibitor messenger RNA in bovine aortic endothelial cells

It is known that either endotoxin (LPS) or interleukin-1 (IL-1) increase the activity of plasminogen activator inhibitor (PAI) in the culture media of human and bovine endothelial cells. We have confirmed these results in bovine aortic endothelial cells (BAEC). To determine if this effect was mediated by increases in the level of PAI messenger RNA (mRNA) we examined the effects of these cytokines on PAI mRNA levels in BAEC, using RNA blot analyses. Treatment of BAEC with either IL-1, LPS, or human recombinant tumor necrosis factor/cachectin (TNF) dramatically increased the level of PAI mRNA. Since elevated levels of PAI will decrease fibrinolytic potential, this mechanism is in concert with the known increase in in vivo procoagulant potential induced by these agents and could contribute to thromboembolic phenomena.

Cardiac and noncardiac atrial natriuretic factor (ANF) biosynthesis and storage and plasma ANF in the rat model of chronic ventricular dysfunction

To evaluate the role of atrial natriuretic factor (ANF) in chronic heart failure (HF), the biosynthesis and storage of ANF in cardiac and noncardiac tissues and the level of plasma ANF were measured in rats exhibiting minimal [2-fold rise in left ventricular end diastolic pressure; myocardial infarct (MI) scar length, 25% left ventricle (LV)] and moderate-severe (3-fold rise in left ventricular end diastolic pressure; decreased contractility (dp/dtmax); MI scar length, 47% LV) chronic HF 30 and 60 days after coronary arterial ligation. In rats with moderate-severe HF (30 days post-MI), the cardiac ANF mRNA concentration (determined by dot blot analysis) increased in three heart chambers [LV, 6-fold; left atria (LA), 3-fold; right ventricle (RV), 2-fold], cardiac immunoreactive ANF (IRANF; determined by RIA) concentration increased on the left side (LV, 7-fold; LA, 33%), but was unchanged (RV) or reduced on the right side (right atria, 33%), and plasma IRANF increased 3-fold above sham control values. Excluding the LV (used for MI scar length), the pattern and magnitude of change in ANF mRNA concentration in moderate-severe HF at 60 days were similar to those at 30 days; the cardiac IRANF concentration at this time was the same (LA) or less than (RV, 66%) sham values, and plasma IRANF increased 6-fold above respective sham values. Generally, the changes in the concentrations of cardiac ANF message and peptide and levels of circulating ANF peptide were smaller in rats with minimal HF. The minute quantities of ANF mRNA and IRANF detected in noncardiac tissues (lung, liver, pituitary, aortic arch, brain, kidney, and salivary gland) were unaltered by HF. These findings show that chronic HF, as defined by hemodynamic and histological measurements, specifically and continuously stimulates atrial as well as ventricular ANF biosynthesis; levels of plasma and cardiac ANF are increased early in HF, but with time are subject to modulation. The cardiac ANF system is the prime locus for the effects of HF, as noncardiac ANF biosynthesis and storage are undisturbed by chronic HF.

Cardiovascular effects and safety of dental anesthesia and dental interventions in patients with recent uncomplicated myocardial infarction

To determine the cardiovascular effects and safety of dental anesthesia and dental interventions in patients within three weeks of uncomplicated acute myocardial infarction, 40 patients were studied. Twenty patients, group 1, underwent injectable local dental anesthesia with 2% lidocaine and 1:100 000 epinephrine. Group 2, 20 patients, underwent vigorous dental prophylaxis (13 patients) or dental extraction (seven patients) after local anesthesia. Heart rate, blood pressure, electrocardiograms, and symptoms were monitored before, during, and after the dental intervention. There were no significant hemodynamic changes or complications related to dental anesthesia or the dental procedures. One patient experienced an asymptomatic, uncomplicated, self-limited, eight-beat run of ventricular tachycardia two hours after dental extraction. Limited dental anesthesia and dental interventions were well tolerated by these patients with recent myocardial infarction.

The value of echocardiographic regional wall motion abnormalities in detecting coronary artery disease in patients with or without a dilated left ventricle

To evaluate the usefulness of echocardiographic regional wall motion abnormalities (RWMA) in detecting coronary artery disease (CAD) in patients with left ventricular (LV) dysfunction and a normal-sized or dilated left ventricle, 103 patients were studied by two-dimensional echocardiography (2DE) and cardiac catheterization. In 60 patients (group I) who had LV dysfunction and a dilated left ventricle by echo (patients with dilated cardiomyopathy), RWMA were detected in 44 patients and 38 (86%) of them had significant CAD, usually two- or three-vessel obstruction; of the 16 patients with dilated cardiomyopathy (DCM) and diffuse LV hypokinesis, eight (50%) had evidence of CAD. Thus the presence of RWMA by 2DE had an 83% sensitivity, a 57% specificity, and a 77% predictive accuracy in detecting CAD in patients with DCM and thus in distinguishing ischemic from idiopathic DCM. In 43 patients with LV dysfunction but normal LV size (group II), the sensitivity, specificity, and predictive accuracy of RWMA in detecting significant CAD was 95%, 100%, and 95%, respectively. We conclude that the detection of RWMA by 2DE is highly suggestive of significant CAD in patients with LV dysfunction and normal-sized or dilated left ventricle; the finding, however, of diffuse LV hypokinesis does not exclude CAD in these patients, especially when the left ventricle is dilated.

Norwalk virus gastroenteritis. An outbreak associated with a cafeteria at a college

An explosive outbreak of gastrointestinal illness occurred among students and employees at a small college in Florida in November 1980. Common symptoms were diarrhea, nausea, weakness, abdominal cramps, chills, vomiting, and low-grade fever. Cases of illness were identified in 40% of 628 students and 15% of 162 employees who responded to a survey. Among students, there was a sevenfold excess risk associated with eating one or more meals at the campus cafeteria November 3-5 (p much less than 0.001). Tossed salad from one meal was strongly associated with illness (p less than 0.0001). Fecal contamination of the salad was documented, although the source of contamination was not identified. Person-to-person spread could not be demonstrated. Seroconversion to Norwalk antigen occurred in significantly more cases (5/6) than noncases (1/6) (p = 0.04).

Effect of polyethylene glycol on the kinetic behaviour of pyruvate kinase and other potentially regulatory liver enzymes

Assay in the presence of 10% polyethylene glycol has been systematically used with potentially regulatory liver enzymes as an indirect way to induce aggregation of enzymes corresponding to that which could occur at their physiological concentrations. Pyruvate kinase L was markedly affected by polyethylene glycol, as was muscle phosphorylase a, while pyruvate kinase M as well as glucokinase, fructose-1,6-bisphosphatase and other liver enzymes examined were not affected.

Long-lasting behavioral effects of bromocriptine in cats

The objective was to determine the behavioral effects and duration of action of bromocriptine (BC) doses from 6 to 60 mg/kg i.p. Cats were housed in large outdoors cages designed for prolonged observation using an ethological approach. Baseline behavior was measured after a 3 month period of habituation. The frequency of 12 behaviors was then scored continuously over 12 h following BC administration. Cats were also observed for one h at 24, 30, 36 and 48 h post-drug. The behavioral effects of BC were remarkably similar to those of LSD and psilocybin but lasted much longer. Treated cats showed hallucinatory-like and escape behavior. Abnormal involuntary movements such as limb flicks, abortive grooming, and head and body shakes were also evoked with a dose-dependent frequency. Lower doses (6-20) produced generalized arousal, but larger doses (30-60) resulted in a decrease in arousal. After 30 mg/kg, hallucinatory-like behavior and general activity (rubbing, treading, kneading) were high at 48 h post-drug, but there were no longer abnormal movements. Behavioral suppression followed the 60 mg/kg dose and peak effects were at 96 h post-injection. This model may prove useful to further study the neural basis of the psychoactive effects of BC.

Effect of Ala-2-D-Trp-8-D-Cys-14-somatostatin on the arginine induced release of insulin, GH and glucagon in normal men

The effects of several doses of somatostatin (SS) and the analog Ala-2-D-Trp-8-D-Cys-14-SS on the arginine-induced release of insulin, glucagon, and GH were compared in a group of normal human subjects. Somatostatin suppressed the release of insulin, glucagon and GH when administered in a dose of 100 micrograms/hr. The same dose of Ala-2-D-Trp-8-D-Cys-14-SS inhibited GH and glucagon release, but although insulin levels were decreased about 24%, this inhibition was not significant statistically. Higher doses of Ala-2-D-Trp-8-D-Cys-14-SS (300 micrograms/hr) induced a partial inhibition of insulin secretion and completely blocked GH release. These results indicate that in humans this analog is a less potent inhibitor of insulin release than somatostatin.

Influence of dietary purines on pool size, turnover, and excretion of uric acid during balance conditions. Isotope studies using 15N-uric acid

Pool size, turnover, and excretion of uric acid were investigated in three normal subjects both during purine-free, isoenergetic liquid formula diet and during additional purine administration by use of isotope dilution techniques. The fractional turnover of the uric acid pool was increased during dietary purine administration suggesting an increased total body uric acid clearance as a result of the increase in renal clearance. Fractional turnover increased more in the female subject than in males, while pool size was increased less. It can be calculated from the results obtained that endogenous uric acid synthesis is not inhibited by dietary purines.

Neuro-ophthalmological study of late yaws and pinta. II. The Caracas project

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