The acute physiological and mood effects of tea and coffee: the role of caffeine level

The objective of this study was to determine the effect of caffeine level in tea and coffee on acute physiological responses and mood. Randomised full crossover design in subjects after overnight caffeine abstention was studied. In study 1 (n = 17) the caffeine level was manipulated naturalistically by preparing tea and coffee at different strengths (1 or 2 cups equivalent). Caffeine levels were 37.5 and 75 mg in tea, 75 and 150 mg in coffee, with water and no-drink controls. In study 2 (n = 15) caffeine level alone was manipulated (water, decaffeinated tea, plus 0, 25, 50, 100, and 200 mg caffeine). Beverage volume and temperature (55 degrees C) were constant. SBP, DBP, heart rate, skin temperature, skin conductance, and mood were monitored over each 3-h study session. In study 1, tea and coffee produced mild autonomic stimulation and an elevation in mood. There were no effects of tea vs. coffee or caffeine dose, despite a fourfold variation in the latter. Increasing beverage strength was associated with greater increases in DBP and energetic arousal. In study 2, caffeinated beverages increased SBP, DBP, and skin conductance and lowered heart rate and skin temperature compared to water. Significant dose-response relationships to caffeine were seen only for SBP, heart rate, and skin temperature. There were significant effects of caffeine on energetic arousal but no consistent dose-response effects. Caffeinated beverages acutely stimulate the autonomic nervous system and increase alertness. Although caffeine can exert dose-dependent effects on a number of acute autonomic responses, caffeine level is not an important factor. Factors besides caffeine may contribute to these acute effects.

A naturalistic investigation of the effects of day-long consumption of tea, coffee and water on alertness, sleep onset and sleep quality

RATIONALE

The effects of caffeine, especially caffeinated coffee, on human performance have been extensively studied. However, few studies have been naturalistic representations of how tea/coffee is normally consumed in terms of dose and time of consumption.

OBJECTIVES

This study investigated the effects of day-long consumption of tea, coffee and water on cognitive and psychomotor performance, and sleep quality at night.

METHODS

Thirty healthy volunteers received equal volume drinks equivalent to either 1 or 2 cups of tea (containing 37.5 mg or 75 mg caffeine), or coffee (75 mg or 150 mg caffeine), or water, in a randomised five-way crossover design. Drinks were administered on four occasions during the day (0900, 1300, 1700 and 2300 hours). A psychometric battery consisting of critical flicker fusion (CFF), choice reaction time (CRT) and subjective sedation (LARS) tests, was administered pre-dose and at frequent time points post-dose. The Leeds Sleep Evaluation Questionnaire (LSEQ) was completed each morning and a wrist actigraph was worn for the duration of the study.

RESULTS

Caffeinated beverages maintained CFF threshold over the whole day (P<0.05), independent of caffeine dose or beverage type. During the acute phase of beverage ingestion, caffeine significantly sustained performance compared to water after the first beverage for CFF and subjective sedation (P<0.05), and after the second beverage for the Recognition component of the CRT task (P<0.05). Additionally, there were significant differences between tea and coffee at 75 mg caffeine after the first drink. Compared to coffee, tea produced a significant increase in CFF threshold between 30 and 90 min post-consumption (P<0.01). However, following the second beverage caffeinated coffee at 75 mg significantly improved reaction time (P<0.05), compared to tea at the same dose, for the Recognition component of the CRT task. Caffeinated beverages had a dose dependent negative effect on sleep onset (P<0.001), sleep time (P<0.001) and sleep quality (P<0.001).

CONCLUSIONS

These results indicate that ingestion of caffeinated beverages may maintain aspects of cognitive and psychomotor performance throughout the day and evening when caffeinated beverages are administered repeatedly. This study also demonstrates that day-long tea consumption produces similar alerting effects to coffee, despite lower caffeine levels, but is less likely to disrupt sleep. Other differences between tea and coffee were more subtle, and require further investigation.

Maintenance of bone density: outcomes over five years of attendance at an osteoporosis center

BACKGROUND

This is a longitudinal analysis of the data from women who visited the Osteoporosis Prevention Center for at least five years. The study is part of an ongoing evaluation of the results of the Center visits.

METHODS

A random sample of 100 women who had attended the clinic for more than five years and were not referred for a definite medical diagnosis was pulled from the records. Descriptive statistics were compiled on this sample. Seventy-five women were postmenopausal and over 49 years of age. This subgroup was studied for change in bone mineral density (BMD) over the five years.

RESULTS

The BMD change was 0.03 gm/cm2 in the spine, -0.01 gm/cm2 in the femoral-neck. and -0.008 gm/cm2 at the radius over the five years.

CONCLUSION

Attendance at the Osteoporosis Prevention Center was associated with maintenance of bone density in the spine over a five-year period.

Role of Na+-glucose cotransport in jejunal meal-induced absorption

In awake dogs, meal ingestion stimulates the absorption of water and electrolytes from neurovascularly intact jejunal Thiry-Vella loops, even though these loops are isolated from the remainder of the gut. This study was designed to investigate the role of Na+-glucose cotransport in mediating this event. Meal ingestion enhanced absorption when the jejunal lumen was perfused with an isotonic solution containing D-glucose, D-galactose, or 3-O-methylglucose. This response was absent when the perfusate contained mannitol or when phlorizin was added to the D-glucose solution. Mucosa from the jejunal loops was serially biopsied and assayed for brush-border Na+-glucose cotransporter (SGLT1) mRNA and protein expression. Although no changes in SGLT1 mRNA levels were observed, protein levels significantly increased within 30 min following meal ingestion. The time course of SGLT1 protein expression corresponded with that of increased Na+ and water absorption. These results suggest that meal-stimulated jejunal absorption may be mediated through an induction of mucosal SGLT1.

Reverse aortic arch flow secondary to severe pulmonary hypertension in the neonate

The purpose of this study is to determine the incidence of reverse aortic arch flow in newborn infants with pulmonary hypertension, and no other identifiable cause for flow reversal, being considered for extracorporeal membrane oxygenation (ECMO) 2) compare the left ventricular output, and 3) outcomes, of these infants, with those in the group of patients with normal arch flow. We reviewed the medical records and echocardiograms of all infants referred to our institution for extracorporeal membrane oxygenation support for pulmonary hypertension, between August 1994 and April 1996. Neonates with pulmonary hypertension and reverse aortic arch flow had significantly lower left ventricular output (p = 0.005), and had significantly higher mortality (p = 0.04), than those with normal aortic arch flow. They required significantly higher ventilatory support (p = 0.01) and tended to need more inotropic support. Reverse aortic arch flow in newborn infants with pulmonary hypertension, and no other cause for the reverse flow, indicates significantly decreased left ventricular output, and may be a marker for a more difficult clinical course and poor prognosis. In this group of patients with pulmonary hypertension, the survival was significantly higher in infants with no PDA or with pure left to right shunt across a PDA.

Factors influencing elevation of intracellular Ca2+ in the MCF-10A human mammary epithelial cell line by carcinogenic polycyclic aromatic hydrocarbons

Carcinogenic polycyclic aromatic hydrocarbons and a halogenated aromatic hydrocarbon, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), were evaluated for their effects on intracellular Ca2+ in the human mammary epithelial cell line MCF-10A. After two 18-h incubations with MCF-10A cells, benzo[a]pyrene (BaP; 1, 3, and 10 microM) produced a dose-dependent increase in intracellular Ca2+. 7,12-Dimethylbenz[a]anthracene increased Ca2+ at 10 microM, whereas 3-methylcholanthrene and TCDD did not. The Ca2+-elevating effect of BaP appeared to be dependent on the influx of extracellular Ca2+, as addition of the Ca2+ chelator EGTA to the extracellular medium prevented the increase in Ca2+. MCF-10A cells were found by polymerase chain reaction to express cytochrome P4501A and P4501B isozymes as well as the aryl hydrocarbon receptor and aryl hydrocarbon receptor nuclear translocator mRNAs associated with cytochrome P450 induction. Certain cytochrome P450-derived metabolites, including benzo[a]pyrene-7,8-diol (BP-diol) and benzo[a]pyrene-7,8-diol-9,10-epoxide (BPDE), were more effective in increasing Ca2+ than was BaP. The Ca2+-elevating effect of BP-diol was prevented by alpha-naphthoflavone, a cytochrome P4501A and P4501B inhibitor, but not by the antioxidant N-acetylcysteine. These results suggest that cytochrome P450-dependent formation of BPDE from BP-diol is a major mechanism required for elevation of Ca2+ in MCF-10A cells.

Intensification of preoperative chemotherapy for osteogenic sarcoma: results of the Memorial Sloan-Kettering (T12) protocol

PURPOSE

It has been observed previously in osteosarcoma (OS) that the degree of necrosis of the resected primary tumor following a period of preoperative chemotherapy is predictive of subsequent event-free survival (EFS). The aim of this study was to determine if more intensive preoperative chemotherapy would increase the proportion of patients with a good histologic response and improve EFS.

PATIENTS AND METHODS

Seventy-three patients with OS were treated at Memorial-Sloan Kettering Cancer Center (MSKCC) on the T12 protocol between 1986 and 1993. Patients were randomized between therapy based on the T10 protocol and therapy with more intensive preoperative chemotherapy. The more intensive preoperative regimen consisted of two courses of cisplatin (CDDP) and doxorubicin (DOX) in addition to the usual preoperative regimen of high-dose methotrexate (HD MTX) and bleomycin, cyclophosphamide, and dactinomycin (BCD).

RESULTS

The regimen with more intensive preoperative chemotherapy achieved a modest increase in the proportion of patients with a good histologic response (44% with a grade III or IV histologic response v 37% in the control arm, 33% with grade IV histologic response v 13% in the control arm). EFS continued to correlate with histologic response. The actuarial 5-year EFS in patients with localized disease was 78% for the regimen with more intensive preoperative chemotherapy and 73% for the control arm.

CONCLUSION

Despite modest increases in the proportion of patients with good histologic response with intensified preoperative chemotherapy, no improvement in EFS was observed.

Effects of cisapride on QT interval in children

Recent reports of torsade de pointes and heart block associated with prolonged QT interval in children receiving cisapride raise questions about its safety. We prospectively examined the effects of cisapride on the QT interval in children. Electrocardiography was performed on 30 children before and after cisapride was administered. An additional 71 children underwent electrocardiography only after starting cisapride. The incidence of a corrected QT (QTc) interval > 440 msec or a marked abnormality in T wave morphology was determined in all 101 children. Cisapride significantly lengthened the QTc with a mean increase of 15.5 +/- 4.6 msec (mean +/- SEM, p = 0.002 in the 30 children with baseline electrocardiographs. Twelve of the 101 patients were found to have a QTc > 440 msec, and one had a new prominent notched T wave in all leads. In these 13 (13%) patients with repolarization abnormalities, other factors that might contribute to a long QT were noted in 11 (85%) patients. We conclude that cisapride use in children is associated with a modest increase in QT interval. The incidence of QTc > 440 msec is low. Most children with long QTc have other factors that could compound the effects of cisapride.

Putting evidence into practice

A training module is described in which experienced health care managers from developing countries explore the challenges to be faced when attempting to use the results of systematic reviews of scientific studies on health care interventions in policy and practice.

Is anyone speaking my language?

This paper describes an on-going three-phase action research project undertaken by members of the Norwich Community Trust speech and language therapy adult services team. With the support of the Clinical Audit department the project was set up in order to: 1) investigate the characteristics, needs and aspirations of the population of dysphasic people in the community; 2) examine how dysphasic people and their families perceive the speech and language therapy service; 3) implement specific changes to the speech and language therapy service to dysphasic people and their families. These changes are based on proposals developed through a working partnership between the speech and language therapy department and dysphasic people and their families.

Lower limb injuries to passenger car occupants

A detailed examination was undertaken of hospitalized car occupants who sustained a lower limb injury in a frontal crash. The assessment included an analysis of the type, severity and causes of these injuries and mechanisms involved in lower limb fractures. The findings showed that fractures and dislocations occurred in 88% of lower limb injury cases, that more than half were from crashes < 48 km hour-1 and that the number of fractures was directly proportional with delta V. Ankle dislocations and foot fractures from the floor and toe pand were the most common injury-source combination overall. The most frequent mechanisms of lower limb fracture were compression, perpendicular loading of the knee and crushing or twisting of the foot. The study points to the need for further regulation to reduce lower limb fractures in frontal crashes and highlights a number of possible countermeasures.

Effects of hot tea, coffee and water ingestion on physiological responses and mood: the role of caffeine, water and beverage type

Psychopharmacological studies using caffeinated beverages or caffeine have rarely considered temporal effects on psychological and physiological function or the specific contribution of caffeine, hot water, or beverage type to the observed effects. The effect of 400 ml hot tea, coffee, and water consumption on systolic and diastolic blood pressure (SBP and DBP), heart rate, skin conductance (a measure of sympathetic nervous system activation), skin temperature, salivary cortisol, and mood were monitored in 16 healthy caffeine-withdrawn (14 h) subjects in a complete crossover design. Beverages were ingested with/without 100 mg caffeine and milk (tea/coffee only). Hot beverage ingestion rapidly increased skin conductance and temperature (+1.7 degrees C) with peak effects observed only 10-30 min post-consumption. Caffeine in the beverage rapidly augmented skin conductance responses but, in contrast to the effect of hot water, reduced the skin temperature response and increased SBP (+2.8 mmHg) and DBP (+2.1 mmHg) 30-60 min post-consumption. Both caffeine and milk addition to beverages independently improved mood and reduced anxiety 30 and 60 min post-consumption. Milk addition had no other effects apart from attenuating the transient increase in physiological responses associated with the drinking phase. There were no effects of beverage consumption on salivary cortisol or of beverage vehicle on salivary caffeine levels, the latter indicating that caffeine pharmacokinetics was similar in both tea and coffee, and not different from caffeinated water. In keeping with this, the responses to tea and coffee ingestion were similar and largely accounted for by the effects of hot water and caffeine. However, tea potentiated the increase in skin temperature compared to coffee and water indicative of a greater vasodilatory response plausibly related to the presence of flavonoids in tea. We conclude that ingestion of hot caffeinated beverages stimulates physiological processes faster than hitherto described, primarily via the effects of hot water and caffeine, but with beverage type and milk playing important modulatory roles.

1H magnetic resonance spectroscopy reveals neuronal injury in a simian immunodeficiency virus macaque model

Infection with human immunodeficiency virus (HIV) commonly results in neurologic disease called the AIDS dementia complex. Neuronal loss and injury have been found in the HIV brain, but the underlying mechanisms are not understood. The simian immunodeficiency virus (SIV)-infected macaque is an excellent animal model for HIV infection, but neuronal loss has not been demonstrated. To determine whether neuronal damage occurs in the SIV brain, we quantified the neuronal marker N-acetylaspartate (NAA) using proton magnetic resonance spectroscopy (1H-MRS) in brain extracts of control and SIV-infected macaques and correlated these findings with histologic analyses. We found reduced NAA in the SIV-infected animals compared with controls (2.94 +/- 1.37 versus 6.21 +/- 1.73 micromol/g of wet weight; p = 0.004). A significant decrease in NAA was also found in SIV-infected animals sacrificed in the acute stages of infection 9 or 10 days after inoculation with SIVmacYnef. We conclude that SIV infection of rhesus macaques results in neuronal damage that is demonstrable shortly after infection and that 1H-MRS may be used to measure such injury. The results further support the SIV macaque as a useful model to study the mechanisms of neuropathogenesis by HIV.

Stress infrared telethermography is useful in the diagnosis of complex regional pain syndrome, type I (formerly reflex sympathetic dystrophy)

OBJECTIVE

To assess the sensitivity, specificity, and predictive value (PV) of stress infrared telethermography (IRT) in the complex regional pain syndrome, type I (CRPS-I).

METHODS

One hundred eighty-five consecutive patients (47 men, 138 women) with 205 pairs of chronically painful limbs (upper, lower, or both) were examined by pain specialists in neurology, physiatry, and anesthesia, who then reached a consensus diagnosis. A clinical diagnosis of CRPS-I required at least two of the following observations: burning pain, vasomotor changes, diaphoresis, trophic changes, allodynia. Patients with only one criterion were classified as possible CRPS-I; those with none were judged not to have CRPS-I. Patients and 24 asymptomatic control subjects underwent stress IRT, which was considered positive for CRPS-I if it showed three of the following: quantitative thermal emission of > or = 1.00 degree C, abnormal distal thermal gradient patterns, presence of a "thermal marker," and abnormal response to functional cold water autonomic stress testing.

RESULTS

By clinical criteria, CRPS-I was diagnosed in 73 pairs of limbs; not CRPS-I was diagnosed in 70; and 62 pairs had possible CRPS-I. Excluding possible CRPS-I cases, there were 5 false-negative stress IRTs (sensitivity 93%) and 7 false-positive results (specificity 89%). Based on estimated 50% prior probability for our population, the positive PV is 90% and the negative PV 94%. None of the control subjects exhibited thermographic evidence of CRPS-I.

CONCLUSION

Stress IRT is a sensitive and specific indicator of CRPS-I.

Severe pulmonary hypertension as a cause of reverse aortic arch flow in the neonate: report of two cases

We describe two newborn infants with severe pulmonary hypertension and circulatory collapse. In both cases, pulsed and color flow Doppler studies showed systolic and diastolic reversal of flow in the transverse aortic arch to the level of the innominate artery. No associated cardiac or noncardiac anomalies could explain the reverse flow in the aortic arch. Severe pulmonary hypertension and low left ventricular output were thought to be responsible for the Doppler findings. Reversal of the aortic arch flow in the newborn with pulmonary hypertension may be associated with a poor prognosis, and early consideration of extracorporeal membrane oxygenation in such patients may be indicated.

Thomas Mister of Shipston (1711-80)

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Future directions for resuscitation research. II. External cardiopulmonary resuscitation basic life support

In sudden cardiac deaths outside hospitals, the present performance of external cardiopulmonary resuscitation-basic life support (CPR-BLS), as a bridge to advanced life support (ALS) attempts for restoration of spontaneous circulation (ROSC), still yields suboptimal results. Therefore, future education research should develop more effective, simpler and quicker ways to enable everyone to acquire the necessary BLS skills. Individualized self-training by lay persons is being revived. Although airway control and direct mouth-to-mouth ventilation skills are difficult to acquire, they must continue to be taught to the lay public and health professionals, primarily for use on relatives and friends where infection risk is not a problem. In children and trauma victims, steps A and B alone may be lifesavers. The best way to ventilate and oxygenate during the initiation of brief external CPR-BLS should be re-evaluated. There is a great difference between animals and humans in the behavior of the airway and thorax during coma, and thus in the need for added positive pressure ventilation. During chest compressions in humans, steps A and B are needed. Details deserve re-evaluation. The low perfusion pressures (borderline blood flows) produced by standard external CPR remain the most serious limitation of this method. In spite of extensive efforts so far, novel laboratory research to remedy this limitation is important for the development of more effective emergency artificial circulation. The results of such studies are greatly influenced by different details in animal models. Active compression-decompression (ACD) external CPR, also called 'push-pull' CPR, with a plunger-type device used by hand or a machine, and intermittent abdominal compression (IAC) external CPR are both promising modifications of standard external CPR. Both need further experimental and clinical clarification. For BLS, developing a more effective purely manual CPR-BLS method for help in rapid ROSC should be given high priority. Portable external CPR machines need improvements. They will serve for bridging ROSC-resistant cases through transport and ALS attempts, primarily by freeing the hands of health professionals for more effective sophisticated ALS measures.

Transforming growth factor-beta 1 in a guanidine-extracted demineralized bone matrix carrier rapidly closes a rabbit critical calvarial defect

Transforming growth factor beta 1 (TGF-beta 1) is a polyfunctional regulatory cytokine that has been shown to have roles in extracellular matrix interactions, soft tissue healing, and osteogenesis. Twenty-five microL of recombinant human TGF-beta 1 was added to guanidine-extracted demineralized bone matrix carrier and the implants were used to fill a 14-mm osteoperiosteal critical calvarial defect in New Zealand white rabbit model. The defects were allowed to heal over 4 weeks and the degree of new bone formation was assess by radiodensitometry and undecalcified bone histomorphometry techniques. Implants with TGF-beta 1 showed complete bridging of the gap with new bone in all cases, while the controls showed fibrous tissue repair of the gap with little or no new bone formation. These results demonstrate the ability of TGF-beta 1 to induce new bone in a brief time period in an inactive carrier.

Removal of surface bacteria by irrigation

We examined the efficacy of various irrigation solutions delivered through a power irrigator to remove bacteria from three different surfaces. Titanium, stainless-steel, and cortical bone surfaces were coated with three different bacterial species: Staphylococcus aureus, Pseudomonas aeruginosa, and Staphylococcus epidermidis. They were then irrigated with 1 L of fluid delivered by jet lavage. The fluids tested were normal saline and solutions of bacitracin, neomycin, and soap. One set of specimens was not irrigated, as a control. After irrigation, the specimens were sonicated to remove residual bacteria, and the sonicate was quantitatively cultured to allow evaluation of the amount of residual bacteria on the surface. The results showed that removal of bacteria reflects an interaction between bacterial species, surface characteristics, and irrigation solution. Fewer bacteria were present in all the irrigation groups than in the control. Soap solution was as good as or better than any other solution at removing all three types of bacteria from all three surfaces, although not all of the pairwise comparisons were statistically significant. There was a significant advantage to soap solution over antibiotic irrigant or saline alone in removing Staphylococcus epidermidis from metallic surfaces. The use of soap solution for irrigation seems to improve the removal of some bacteria from some surfaces in this experimental model and may represent a better type of irrigation additive.

Intravenous ribavirin by constant infusion for serious influenza and parainfluenzavirus infection

Three patients with severe lower respiratory tract influenza or parainfluenzavirus infections were treated with continuous ribavirin infusion, given as a 5 mg/kg/hour (h) loading infusion for 8 h followed by 1.5 mg/kg/h for 2 to 6 days. This regimen was generally well tolerated. Plasma ribavirin concentrations were 40 to 60 microM in two patients during the continuous infusion phase and lower concentrations were detectable in tracheobronchial secretions. In temporal association with ribavirin administration, viral shedding diminished in one patient and ceased in two patients, one of whom had developed virus resistant to amantadine. The strategy of continuous ribavirin infusion warrants controlled testing for its antiviral and possible clinical effectiveness.