The effect of caffeine on the serum insulin level during intravenous glucose tolerance test in patients with chemical diabetes

A small but significant number of tritiated thymidine labelled cells were found, by autoradiography, in the glomeruli of rats with Masugi nephritis or chronic serum sickness nephritis. There were no labelled glomerular cells in sections of untreated animals. The findings favour the contention that in proliferative glomerulonephritis, glomerular hypercellularity is due to infiltration of monocytic cells into the tufts where they divide.     

Effects of carbohydrate restriction on the hypoglycemic phase of the glucose tolerance test

A gas-liquid chromatographic method has been developed for the analysis of residues of chlorphoxim, 2-chloro-alpha ((diethoxyphosphinothioyl)oxy)imino)-benzeneacetonitrile, in water and fish. The method is based on the in-block methylation of chlorphoxim with 0.01M trimethylanilinium hydroxide in methanol. The derivative, O,O-diethyl O-methyl phosphorothioate, was determined quantitatively by using a flame photometric detector specific for phosphorus. The in-block reaction is 70% efficient. Water samples were extracted with hexane; fish were extracted with methylene chloride and cleaned up on an acetonitrile-hexane partition column. Recoveries from water and fish samples spiked with chlorphoxim averaged 86.3 and 80.4%, respectively. Limits of detection were 10.0 ppb for 5 g samples of fish and 0.10 ppb for 300 ml water samples.     

Effects of caffeine consumption on delayed conception

The authors examined the effects of caffeine consumption on waiting time to conception in the Reproductive Health Study, a retrospective study of 1,430 non-contracepting, parous women interviewed between July 1989 and June 1990 at Fishkill, New York, and Burlington, Vermont. Information was obtained on 2,501 pregnancies since 1980. Women's reported consumption of caffeinated beverages during the first month of pregnancy was used to estimate daily caffeine intake, which was categorized as none, 1-150, 151-300, and > or = 301 mg. Information on delayed conception was analyzed as a dichotomous variable (< or = 12 months delay vs. > 12 months delay), and the per cycle probability of conception (fecundability) was estimated using waiting time to conception as a continuous variable. Odds ratios of delayed conception and fecundability ratios adjusted for age, parity, smoking, last contraceptive used, infertility history, and race, were estimated by logistic regression and Cox proportional hazard models, respectively. Women who did not smoke and who consumed no caffeine were used as a reference group. The adjusted odds ratio of delayed conception for more than one year was not increased among women who consumed < or = 300 mg of caffeine daily. However, the odds ratio (OR) was 2.65 (95% confidence interval (CI) 1.38-5.07) among nonsmokers who consumed > or = 301 mg of caffeine daily. Although smoking per se was associated with a significant increased risk of delayed conception (OR = 1.77, 95% CI 1.33-2.37), no effect of high caffeine consumption was observed among women who smoked. Fecundability was reduced among nonsmokers who consumed more than 300 mg caffeine daily (fecundability ratio = 0.74, 95% CI 0.59-0.92). Smoking reduced the fecundability ratio, but the authors observed no effect of caffeine consumption on fecundability among women who smoked. Other studies provide biologic plausibility for these findings. The authors conclude that high levels of caffeine consumption may result in delayed conception among women who do not smoke cigarettes.     

Effects of caffeine on visual monitoring.

Examined the effects of caffeine on a protracted visual monitoring task analogous to an aspect of automobile night driving. 100 male undergraduates participated in monitoring 2 red lights that moved apart at random intervals, simulating the rate-of-closure cue of change in visual angle for a vehicle following 60 yd. behind another vehicle. 20 measures of response latency were provided for each S in each of 4 hr. of continuous testing. 5 groups (n = 20) were given the following treatments: placebo, 200 mg. of caffeine at the beginning of the 2nd hr., 200 mg. at the 3rd hr., 400 mg. at the 2nd, and 400 mg. at the 3rd. Results indicate that caffeine significantly inhibited response blocking (attention lapses). The effects were apparent within l hr. following administration and persisted over the remaining time. No difference was found between dosage levels or in magnitude of effect at the different administration times. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of caffeine withdrawal on humans living in a residential laboratory.

Caffeine withdrawal was examined in caffeine-dependent humans living in a residential laboratory. Ten men and 2 women who reported daily caffeine consumption participated in a 17-day study. From 1000–1700, participants worked on computerized tasks assessing memory, vigilance, and psychomotor skills, with a 1-hr break for lunch. From 1700–2330, participants engaged in private or social, recreational activities. Subjective-effects measures were completed 10 times per day. Participants were maintained on caffeine (100 mg 3 times a day at 0945, 1345, and 1745), except on days 5–6 and 12–13, when caffeine was replaced by placebo. Caffeine abstinence selectively influenced subjective effects without altering social behavior or performance on tasks assessing memory, vigilance, and psychomotor skills. Furthermore, the effects of caffeine on food intake were enhanced after 2 days of caffeine abstinence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of acute caffeine administration on adolescents.

Acute caffeine administration has physiological, behavioral, and subjective effects. Despite its widespread use, few studies have described the impact of caffeine consumption in children and adolescents. The purpose of this study was to investigate the effects of acute caffeine administration in adolescents. We measured cardiovascular responses and snack food intake after acute administration of 0 mg, 50 mg, 100 mg, and 200 mg of caffeine. We also compared usual food intake and subjective effects of caffeine between high- and low-caffeine consumers. Finally, we conducted a detailed analysis of caffeine sources and consumption levels. We found main effects of caffeine dose on heart rate (HR) and diastolic blood pressure (DBP), with HR decreasing and DBP increasing with increasing caffeine dose. There were significant interactions among gender, caffeine use, and time on DBP. High caffeine consumers (>50 mg/day) reported using caffeine to stay awake and drinking coffee, tea, soda, and energy drinks more than low consumers (     

Effects of caffeine on anxiety and depression.

Administered the Multiple Affect Adjective Check List to 157 Ss (mean age, 24.88 yrs) both before and 1 hr after double-blind administrations of 0, 150, or 300 mg of caffeine per 45.36 kg and after controlling for caffeine tolerance. Caffeine increased anxiety, depression, and hostility. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prevalence of retinopathy in people with diabetes, impaired glucose tolerance, and normal glucose tolerance

OBJECTIVE: Recently, an international expert committee published new revised criteria for diagnosing diabetes. According to the new criteria, the 2-h glucose level for diabetes in the oral glucose tolerance test (OGTT) is the same as in the previous World Health Organization criteria, but the cut point for the fasting blood glucose level has been lowered to be equivalent to the 2-h OGTT level. Measurement of the fasting blood glucose level is preferred to the 2-h OGTT glucose level. The ability of the new cut point for fasting blood glucose to discriminate between those at a high and a low risk for retinopathy was tested in a population-based study RESEARCH DESIGN AND METHODS: The population consisted of all the 1,008 subjects (456 men) born in 1935 and living in a Finnish city A screening for type 2 diabetes was carried out in the first phase. All participants who were not on antidiabetic medication were invited for an OGTT in the second phase. A fasting blood glucose value was measured from the diabetic subjects on antidiabetic medication. In addition, measurements of serum cholesterol, HDL cholesterol, and triglycerides were made, and fundus photographs were taken. Altogether, 831 subjects (368 men) (82%) participated and constitute the eligible study population for the present analyses. Fundus photographs were available for 790 subjects (347 men) (95%). RESULTS: There were 28 subjects (3.5%) who had mild retinopathic changes in the fundus photographs. Retinopathic changes were associated with higher fasting blood glucose levels, but not with any of the other background factors. The prevalence of retinopathy was 10.2% (95% CI 4.8-18.5) in subjects with a fasting blood glucose of > or =6.1 mmol/l, while it was 2.6% (1.5-4.0) in those with a lower fasting blood glucose level. In the former group, a majority (seven of nine) of the subjects with retinopathy were previously diagnosed diabetic patients. Some cases of retinopathy were found regardless the level of glycemia, and measurement of the 2-h OGTT glucose levels did not increase information. CONCLUSIONS: The results of this population study give support to the use of fasting blood glucose levels in diagnosing type 2 diabetes. The lower limit of the highest decile of the fasting glucose level was 6.1 mmol/l, and it discriminated subjects at a high risk for retinopathy from those at a low risk. Because of the limited number of subjects with retinopathy in this study, the level of hyperglycemia associated with retinopathy cannot be estimated accurately.     

Effects of delmadinone acetate on pituitary-adrenal function, glucose tolerance and growth hormone in male dogs

OBJECTIVE: To characterise the effects of delmadinone acetate on the pituitary-adrenal axis, glucose tolerance and growth hormone concentration in normal male dogs and dogs with benign prostatic hyperplasia. DESIGN: A prospective study involving nine normal male dogs and seven with prostatic hyperplasia. PROCEDURE: Delmadinone acetate was administered to six normal male dogs and seven dogs with benign prostatic hyperplasia at recommended dose rates (1.5 mg/kg subcutaneously at 0, 1 and 4 weeks). Three normal controls received saline at the same intervals. Blood concentrations of ACTH, cortisol, glucose, insulin and growth hormone were measured over 50 days. Intravenous glucose tolerance and ACTH response tests were performed before and after treatment in the nine normal animals. RESULTS: A substantial suppression of basal and 2 h post-ACTH plasma cortisol secretion was demonstrated after one dose in all dogs given delmadinone acetate. Individual responses after the second and third administration varied between recovery in adrenal responsiveness to continued suppression. Plasma ACTH concentration was also diminished after one treatment. No effects were evident on glucose tolerance or serum growth hormone concentrations. CONCLUSION: Delmadinone acetate causes adrenal suppression from inhibition of release of ACTH from the pituitary gland. Treated dogs may be at risk of developing signs of glucocorticoid insufficiency if subjected to stressful events during or after therapy. Neither glucose intolerance nor hypersomatotropism seems likely in male dogs given delmadinone acetate at the recommended dose rate, but the potential for excessive growth hormone secretion in treated bitches remains undetermined.     

Clinical effects of buspirone in social phobia: a double-blind placebo-controlled study

BACKGROUND: The results of open pilot studies suggest that the serotonin-1A (5-HT1A) receptor agonist buspirone might be effective in social phobia. METHOD: In the present study, the efficacy of buspirone was investigated in patients with social phobia using a 12-week double-blind placebo-controlled design. Thirty social phobic patients (DSM-IV) were treated with either buspirone 30 mg daily or placebo. Efficacy of treatment was measured using the Social Phobia Scale (subscores anxiety and avoidance) and the Hamilton Rating Scale for Anxiety. RESULTS: Taking a reduction of 50% or more on the Social Phobia Scale as a criterion for clinically relevant improvement, only 1 patient on buspirone and 1 on placebo were classified as responder to treatment. A subjective and clinically relevant improvement was reported by 4 patients (27%) on buspirone and 2 patients (13%) on placebo. There were no statistically significant differences between buspirone and placebo on any of the outcome measures. Generally speaking, buspirone was well tolerated. CONCLUSION: The results of the study do not support the results of open studies, in which a reduction of social anxiety and social avoidance was reported in patients with social phobia treated with buspirone.     

Effect of piracetam on recovery and rehabilitation after stroke: a double-blind, placebo-controlled study

The nootropic agent piracetam has been shown to improve learning and memory, and it may, by this means, facilitate recovery and rehabilitation after a stroke. We report the results of a pilot study exploring its effects in patients undergoing rehabilitation after acute cerebral infarction in the carotid artery territory. We compared piracetam and placebo, each given for 12 weeks, in a multicenter, double-blind, randomized trial of parallel-group design; testing was performed at baseline (6-9 weeks poststroke), weeks 5 and 12, and, in fewer patients, 12 weeks after termination of treatment. Standardized tests of activities of daily living (Barthel Index, Kuriansky Test), aphasia (Aachen Aphasia Test), and perception (Rivermead Perception Assessment Battery) were the primary efficacy variables. Of 158 patients, 137 (81 males, 56 females) were studied after treatment and 88 at 24-week follow-up. Thirty patients on piracetam (45%) and 37 on placebo (53%) were aphasic on entry. Both groups, including the subgroups with aphasia, were well matched at baseline for demographic data, stroke sequelae, type and severity of aphasia, and prognostic parameters. Multivariate analysis of Aachen Aphasia subtest scores showed a significant overall improvement relative to baseline in favor of piracetam (p = 0.02) at 12 weeks. This was not seen at 24 weeks when, however, fewer patients were available for evaluation so that we could neither confirm nor deny whether improvement was maintained after cessation of piracetam. We were unable to demonstrate an effect on tests of activities of daily living and could neither confirm nor exclude an effect on perceptual deficit. We have shown an improvement in aphasia in patients undergoing rehabilitation after a stroke after 12 weeks' treatment with piracetam that requires confirmation in further studies.     

Treatment of inclusion-body myositis with IVIg: a double-blind, placebo-controlled study

The hypothesis was tested that 7-sulfooxymethylbenz[a]anthracene (7-SBA) is an ultimate electrophilic and carcinogenic form of 7-hydroxymethylbenz[a]anthracene. In conformity with this hypothesis, 7-SBA was more carcinogenic than 7-HBA in inducing sarcomas at the site of repeated subcutaneous injection. These metabolites were individually administered to female Sprague-Dawley rats, beginning at 30 days of age, in 0.2 mumol doses given three times each week for 20 doses. One year after the first injection of 7-SBA, seven of thirteen female Sprague-Dawley rats had developed sarcomas. 7-HBA, on the other hand, had induced sarcomas at the site of injection in only two of tweleve rats. No tumors developed either in the control group given sesame oil:DMSO only or in the untreated control group. It would appear from the results summarized here that the search for an ultimate electrophilic and carcinogenic form of 7-HBA has been successful.     

Human brain metabolic response to caffeine and the effects of tolerance

OBJECTIVE: Since there is limited information concerning caffeine's metabolic effects on the human brain, the authors applied a rapid proton echo-planar spectroscopic imaging technique to dynamically measure regional brain metabolic responses to caffeine ingestion. They specifically measured changes in brain lactate due to the combined effects of caffeine's stimulation of glycolysis and reduction of cerebral blood flow. METHOD: Nine heavy caffeine users and nine caffeine-intolerant individuals, who had previously discontinued or substantially curtailed use of caffeinated products because of associated anxiety and discomforting physiological arousal, were studied at baseline and then during 1 hour following ingestion of caffeine citrate (10 mg/kg). To assess state-trait contributions and the effects of caffeine tolerance, five of the caffeine users were restudied after a 1- to 2-month caffeine holiday. RESULTS: The caffeine-intolerant individuals, but not the regular caffeine users, experienced substantial psychological and physiological distress in response to caffeine ingestion. Significant increases in global and regionally specific brain lactate were observed only among the caffeine-intolerant subjects. Reexposure of the regular caffeine users to caffeine after a caffeine holiday resulted in little or no adverse clinical reaction but significant rises in brain lactate which were of a magnitude similar to that observed for the caffeine-intolerant group. CONCLUSIONS: These results provide direct evidence for the loss of caffeine tolerance in the human brain subsequent to caffeine discontinuation and suggest mechanisms for the phenomenon of caffeine intolerance other than its metabolic effects on elevating brain lactate.     

Randomized, double-blind, placebo-controlled study of carvedilol on the prevention of nitrate tolerance in patients with chronic heart failure

OBJECTIVES: This study was designed to evaluate the effect of carvedilol on nitrate tolerance in patients with chronic heart failure. BACKGROUND: The attenuation of cyclic guanosine 5'-monophosphate (cGMP) production due to inactivation of guanylate cyclase by increased superoxide has been reported as a mechanism of nitrate tolerance. Carvedilol has been known to combine alpha/beta-blockade with antioxidant properties. METHODS: To evaluate the effect of carvedilol on nitrate tolerance, 40 patients with chronic heart failure were randomized to four groups that received either carvedilol (2.5 mg once a day [carvedilol group, n=10]), metoprolol (30 mg once a day [metoprolol group, n=10]), doxazosin (0.5 mg once a day [doxazosin group, n=10]) or placebo (placebo group, n=10). Vasodilatory response to nitroglycerin (NTG) was assessed with forearm plethysmography by measuring the change in forearm blood flow (FBF) before and 5 min after sublingual administration of 0.3 mg NTG, and at the same time blood samples were taken from veins on the opposite side to measure platelet cGMP. Plethysmography and blood sampling were obtained serially at baseline (day 0); 3 days after carvedilol, metoprolol, doxazosin or placebo administration (day 3); and 3 days after application of a 10-mg/24-h NTG tape concomitantly with carvedilol, metoprolol, doxazosin or placebo (day 6). RESULTS: There was no significant difference in the response of FBF (%FBF) and cGMP (%cGMP) to sublingual NTG on day 0 and day 3 among the four groups. On day 6, %FBF and %cGMP were significantly lower in the metoprolol, doxazosin and placebo groups than on day 0 and day 3, but these parameters in the carvedilol group were maintained. CONCLUSIONS: These results indicated that carvedilol may prevent nitrate tolerance in patients with chronic heart failure during continuous therapy with NTG.     

Effects of caffeine on event-related potentials: comparison of oddball with single-tone paradigms

A report is given of the 1st confirmed outbreak of Albizia versicolor poisoning in Malawi and the 1st natural outbreak reported in sheep and goats. Approximately 800 animals are estimated to have died over a 9-year period on a government farm near Lake Malawi. Deaths occurred exclusively from August to December when ripe dry pods that fell to the ground were ingested. The major clinical signs were hyperaesthesia, wild running, lateral recumbency with rapid leg movements, nystagmus and rapid blinking. Approximately 75% of clinical cases made a full and rapid recovery. Sheep more often showed signs of poisoning than goats which was attributed to inherent susceptibility rather than selective feeding. The majority of animals affected were under 1 year of age. A series of experiments was conducted and all animals dosed with 6.4 g/kg or more of dry pods died with typical clinical signs. Although A. versicolor is well known to the local population there appeared to be no appreciation of its toxicity. Poisonings are probably rare under traditional management systems.     

Effects of influenza vaccination in HIV-infected adults: a double-blind, placebo-controlled trial

Annual influenza vaccine is recommended for persons with HIV infection. Recent reports indicate that immunizations may increase HIV replication in infected individuals. Forty-seven HIV-infected patients were randomized to influenza vaccine or saline placebo using a double blind study design. One month after vaccination, plasma HIV-1 RNA increased in the vaccinated but not placebo group (p = 0.029). At 3 months, CD4% dropped an average of 1.6 points in the vaccinated group compared to an increase of 0.1 points in the placebo group (p = 0.039). Patients on stable antiretroviral regimens had CD4% drop an average of 2.3 points in the vaccinated group at 3 months versus 0.1 points in the placebo group (p = 0.015). It is concluded that HIV-infected patients are at risk for increased HIV replication and decreases in CD4% following influenza vaccination. Since influenza has not been associated with significant morbidity in this population, further study of routine influenza vaccination for HIV-infected patients is warranted.     

Sulphasalazine in psoriatic arthritis: a randomized, multicentre, placebo-controlled study

A prospective double-blind, placebo-controlled, randomized study of 24 weeks duration was carried out comparing the efficacy and tolerability of sulphasalazine (SSZ) versus placebo in patients with psoriatic arthritis. A total of 120 patients were included in nine centres. All patients had active disease and fulfilled the criteria of definite psoriatic arthritis of at least 3 months duration. They received either SSZ (2.0 g/day) or placebo. Efficacy variables included pain, patient's overall assessment of joint and skin improvement, morning stiffness, Ritchie articular index, ESR and CRP. An intention-to-treat (ITT) analysis was performed for the 117 patients who qualified (three patients did not qualify due to missing data after baseline). A per-protocol analysis was performed for the 81 patients who completed the 6 months study period (SSZ = 38, placebo = 43). Major reasons for withdrawal were inadequate response (SSZ = 4, placebo = 7) and adverse events (SSZ = 8, placebo = 12). Pain was the only statistically significantly different primary outcome variable at end point in favour of SSZ in the ITT analysis. No significant differences were present in other clinical or biological variables, although there was a trend in favour of SSZ for some variables. SSZ, at a dose of 2.0 g/day, appeared to be a safe treatment in patients with psoriatic arthritis. At this dosage, its efficacy was only demonstrated for the pain variable.