A comparative perspective on brucellar, pyogenic, and tuberculous spondylodiscitis

OBJECTIVE

Non-specific features of spondylodiscitis lead to a delay and challenge in the diagnosis/differential diagnosis/treatment processes, and thus, serious complications may arise. This study aims to compare brucellar, pyogenic, and tuberculous types of spondylodiscitis, considering their demographic, clinical, and laboratory differences. This may provide more rapid management and good outcomes.

PATIENTS AND METHODS

A total of 131 patients with infectious spondylodiscitis were included in the study. The patients were divided into brucellar (n=63), pyogenic (n=53), and tuberculous (n=15) types of spondylodiscitis and compared for demographic, clinical, laboratory, and imaging features.

RESULTS

Tuberculous spondylodiscitis had higher scores for weight loss, painless palpation, thoracic spine involvement, and psoas abscess formation than other spondylodiscitis. Also, tuberculous spondylodiscitis had higher rates of neurologic deficit and lower rates of lumbar involvement than brucellar spondylodiscitis. Pyogenic spondylodiscitis is more likely to occur in patients who have a history of spine surgery compared to other forms of spondylodiscitis. Also, pyogenic spondylodiscitis had higher rates of fever, erythema, paraspinal abscess, white blood cell (WBC), and erythrocyte sedimentation rate (ESR) than brucellar spondylodiscitis. On the other hand, brucellar spondylodiscitis had higher rates of rural living and sweating than pyogenic spondylodiscitis.

CONCLUSIONS

Weight loss, painless palpation, involved thoracic spine, psoas abscess, and neurologic deficit are symptoms favoring tuberculous spondylodiscitis. History of spine surgery, high fever, skin erythema, and paraspinal abscess are findings in favor of pyogenic spondylodiscitis. Rural living, sweating, and involved lumbar spine are symptoms that indicate brucellar spondylodiscitis. These symptoms can be used to distinguish the types of spondylodiscitis.

Does combined usage of FFP2 and Surgical mask against SARS-CoV-2 affect SpO2 values and pulse rates of dental health-care workers?

BACKGROUND AND AIM

Combined use of surgical mask with filtering facepiece (FFP) 2 masks has been popular among the health-care workers. However, the effect of this preference on the vital values of individuals stays as a challenge among the professionals. The present study aimed to assess the effect of FFP2 mask versus combined use of it with surgical mask on the SpO₂ values and pulse rates of individuals.

PATIENTS AND METHODS

This study was conducted on 20 health-care workers. The pulse rates and SpO₂ values were evaluated by pulse oximeter placed in the index fingers of the participants. The participants were divided into two groups: those using the FFP2 mask and those using FFP2-surgical mask combination. Individuals wearing FFP2 mask were examined for a period of 60 min and the same examination was repeated for another period of 60 min in those using combination of FFP2 with surgical mask. The values were measured at the beginning and at 15, 30, 45, and 60 min intervals, respectively. The examinations were conducted in the rest position to obtain standardization.

RESULTS

The observed data showed no statistical difference at all periods in either SpO₂ values or pulse rates between FFP2 and FFP2-surgical mask combined groups. The SpO₂ values reduced from the initial time to 15 min in the FFP2-surgical mask group. Also, in the FFP2-SM group, statistically significant increase in values was observed between 15 and 45 min and 15 and 60 min. Another increase in SpO₂ value was found in the observations made between made 30 and 45 min in the same group (P < 0.05). The pulse rates of the individuals showed no statistical difference in both the groups and at all experimental periods (P > 0.05).

CONCLUSION

According to the present study, wearing only the FFP2 mask or FFP2-surgical mask combination seems not to cause any effect on the SpO₂ values and pulse rates of the participants.

The Relation of End-Tidal CO 2 Values With Infarct Volume and Early Prognosis in Patients With Acute Ischemic Stroke

BACKGROUND

The aim of this study is to reveal the relationship between end-tidal CO 2 (EtCO 2 ) values with infarct volume and early prognosis in patients diagnosed with acute ischemic stroke in the emergency department.

MATERIALS AND METHODS

This prospective cross-sectional study was conducted in a tertiary hospital. The demographics, characteristics, EtCO 2 , volume of the stroke area on diffusion-weighted magnetic resonance imaging and the modified Rankin Scale (mRS) of the patients were recorded. The values calculated at admission and at discharge were labeled as "mRS-1" and "mRS-2," respectively, and the mRS-2 measurement was used as a prognostic indicator. The "good" and the "poor" functional outcomes were defined as mRS ≤2 and mRS >2, respectively. Correlations between levels of EtCO 2 and infarct volume, mRS were calculated.

RESULTS

In total, 44 patients were included in the study. The median age of the patients was 69 years (interquartile range; 16; min-max: 35 to 88 y) and 68.2% of them were male. In the univariate logistic regression models of the mRS-2 [0 to 2 (0) and 3 to 6 (1)], all variables were not statistically significant to predict mRS-2 group. There were statistically significant differences in EtCO 2 values between mRS-1 ( P =0.03) and mRS-2 ( P =0.04). A negative moderate correlation was found between EtCO 2 and mRS-2 ( r =-0.410; P =0.006). The correlation between EtCO 2 and infarct volume was not statistically significant ( r =-0.256; P =0.093).

CONCLUSIONS

This study highlights the importance of capnography follow-up of patients with acute ischemic stroke. In patients with acute ischemic stroke, the EtCO 2 value measured at the time of admission is lower in the group with high mRS at both admission and discharge.

Characteristics and Outcomes of Patients With Cerebral Venous Sinus Thrombosis in SARS-CoV-2 Vaccine-Induced Immune Thrombotic Thrombocytopenia

Importance

Thrombosis with thrombocytopenia syndrome (TTS) has been reported after vaccination with the SARS-CoV-2 vaccines ChAdOx1 nCov-19 (Oxford-AstraZeneca) and Ad26.COV2.S (Janssen/Johnson & Johnson).

Objective

To describe the clinical characteristics and outcome of patients with cerebral venous sinus thrombosis (CVST) after SARS-CoV-2 vaccination with and without TTS.

Design, Setting, and Participants

This cohort study used data from an international registry of consecutive patients with CVST within 28 days of SARS-CoV-2 vaccination included between March 29 and June 18, 2021, from 81 hospitals in 19 countries. For reference, data from patients with CVST between 2015 and 2018 were derived from an existing international registry. Clinical characteristics and mortality rate were described for adults with (1) CVST in the setting of SARS-CoV-2 vaccine-induced immune thrombotic thrombocytopenia, (2) CVST after SARS-CoV-2 vaccination not fulling criteria for TTS, and (3) CVST unrelated to SARS-CoV-2 vaccination.

Exposures

Patients were classified as having TTS if they had new-onset thrombocytopenia without recent exposure to heparin, in accordance with the Brighton Collaboration interim criteria.

Main Outcomes and Measures

Clinical characteristics and mortality rate.

Results

Of 116 patients with postvaccination CVST, 78 (67.2%) had TTS, of whom 76 had been vaccinated with ChAdOx1 nCov-19; 38 (32.8%) had no indication of TTS. The control group included 207 patients with CVST before the COVID-19 pandemic. A total of 63 of 78 (81%), 30 of 38 (79%), and 145 of 207 (70.0%) patients, respectively, were female, and the mean (SD) age was 45 (14), 55 (20), and 42 (16) years, respectively. Concomitant thromboembolism occurred in 25 of 70 patients (36%) in the TTS group, 2 of 35 (6%) in the no TTS group, and 10 of 206 (4.9%) in the control group, and in-hospital mortality rates were 47% (36 of 76; 95% CI, 37-58), 5% (2 of 37; 95% CI, 1-18), and 3.9% (8 of 207; 95% CI, 2.0-7.4), respectively. The mortality rate was 61% (14 of 23) among patients in the TTS group diagnosed before the condition garnered attention in the scientific community and 42% (22 of 53) among patients diagnosed later.

Conclusions and Relevance

In this cohort study of patients with CVST, a distinct clinical profile and high mortality rate was observed in patients meeting criteria for TTS after SARS-CoV-2 vaccination.

The predictor role of metacognition and emotion recognition in internet gaming disorder among late adolescents

Introduction

Internet gaming is acknowledged as a common leisure activity among adolescents yet only a little known about the pscyhodevelopmental roots. Emotion recognition and metacognition which are proved to be determinants in behavioral disorders may be considered salient factors in also internet gaming disorder (IGD).

Objectives

The research to date has focused on psychological comorbidities rather than risk factors (e.g. dysfunctional metacognitive beliefs, emotion recognition deficits), whereas, improved early intervention would be more likely if risk factors were well defined, especially before the onset of the illness. The objective of this study was to investigate these areas by analyzing associations between metacognitive beliefs, emotion recognition, and IGD among late adolescents with tendency for pathological gaming behavior.

Methods

806 high school students were recruited and instructed to take Internet Gaming Disorder Scale (IGDT), Meta-Cognitions Questionnaire for Children and Adolescents (MCQ-C) and Reading the Mind in the Eyes Test - Children’s Version (RMET).

Results

Mean comparisons corresponding to IGD risk potential showed that positive meta-worry and superstitious, punishment, and responsibility beliefs of MCQ-C were significantly higher in the risky group, whereas; RMET neutral subtest was significantly higher in the non-risky group. Additionally, a positive correlation was found in all subtests of MCQ-C, RMET positive emotions and IGD. Regression analysis revealed that RMET positive subtest and positive meta-worry of MCQ-C predict IGD risk.

Conclusions

The findings of the study partially corroborated the early results found among early adolescents; however, they also indicated the requirement of distinct therapeutic approach for cognitive interventions of IGD in late adolescence period.

Disclosure

No significant relationships.

The relationship between cognitive test anxiety and mindfulness among university students

Introduction

Cognitive test anxiety is acknowledged as intense anxiety that prevents the effective use of the previously learned knowledge during the exam and leads to a decrease in success. Mindfulness is indicated as the ability to bring one’s attention to experiences in the present moment in a non-judgmental way. Despite promising outcomes of mindfulness techniques in regulating stress levels, much uncertainty still exists about the specific associations between cognitive test anxiety and mindfulness subcategories.

Objectives

The aim of this study was to investigate the relationship between cognitive test anxiety and subcategories of mindfulness among university students which may help improving current mindfulness interventions that show promising results to tackle cognitive test anxiety.

Methods

One hundred-eighty-two university students were recruited for the study via online forms. Mindfulness was measured with Five Facet Mindfulness (FFMQ-S) and the cognitive test anxiety was assessed with Cognitive Test Anxiety Scale-Revised (CTAR).

Results

Total scores of CTAR-R has an association between subscales of FFMQ; act-aware and non-judge in a positive direction, whereas; observe and describe in a negative direction. In addition, according to our regression model, FFMQ subscales of describing to indicated lower levels of CTAR scores, whereas act aware and non-judge indicated higher levels of CTAR scores.

Conclusions

The findings of the study partially corroborated the previous results by offering inferences about the subcategories of mindfulness. Additionally, these findings suggest that current interventions may target specific subcategories of mindfulness to maximize the positive outcomes of the treatment.

Disclosure

No significant relationships.

Effects of entecavir, tenofovir and telbivudine treatment on renal functions in chronic hepatitis B patients

BACKGROUND AND STUDY AIMS

The aim of this study was to enlighten the controversy about the renal safety of entecavir, tenofovir, and telbivudine treatments in chronic hepatitis B (CHB) patients by comparing these treatments in real-world conditions.

PATIENTS AND METHODS

We retrospectively enrolled 104 treatment-naive patients with CHB monoinfection into our study. Patients were treated with entecavir monotherapy (n=38), tenofovir monotherapy (n=35), or telbivudine monotherapy (n=31). We then compared and statistically analyzed the effects of these drugs on the estimated glomerular filtration rate (eGFR) over a 24-month follow-up period.

RESULTS

In the entecavir group, time-dependent change in eGFR was not statistically significant (p = 0.357). There was a statistically significant increase in eGFR in the telbivudine group at 12 months (p<0.001) and at 24 months (p<0.001) and, in contrast, a statistically significant decrease in the tenofovir group at 12 months (p<0.001) and at 24 months (p<0.001). There was no significant relationship between entecavir and eGFR change (p = 0.763). We found that tenofovir and telbivudine were independent predictors of eGFR change (decrease in eGFR, p<0.001 and increase in eGFR, p = 0.001, respectively).

CONCLUSIONS

We recommend close follow-up of renal functions, especially for patients treated with tenofovir. Telbivudine was superior to the other drugs in terms of renal function. We conclude that an individualized therapy program considering treatment efficacy and side effects is the best option for patients.

Medially displaced common and internal carotid arteries presenting as a pulsatile mass: Clinicoradiologic analysis of 62 cases

We conducted a prospective study to analyze the medially displaced courses of the common carotid artery (CCA) and the cervical segment of the internal carotid artery (ICA) in patients who were diagnosed with a pulsatile mass on nasopharyngolaryngoscopy and by clinicoradiologic findings. Our study group was made up of 62 patients-40 women and 22 men, aged 30 to 88 years (mean: 63.7)-who presented with a submucosal pseudomass or a bulging mass on the pharyngeal wall with obvious pulsation. For comparison purposes, we recruited a control group of 62 consecutively presenting patients who had been admitted to our Neurology Department with acute severe headache and who had undergone CT angiography based on a suspicion of an aneurysm or a vertebral or carotid artery dissection. A medially displaced carotid artery was identified in all patients in the study group. Two main course abnormalities were observed: (1) a pharyngeal superficial placement (PSP), consisting of a bulging or placement immediately adjacent to the naso-orohypopharyngeal lumen, and (2) a retropharyngeal midline placement (RMP), which entailed medialization of the carotid arteries to the midline. A PSP was observed in 11 patients, an RMP was found in 17 patients, and both were seen in 34 patients. The distance from the aberrant carotid artery to the pharyngeal wall and to the retropharyngeal midline of the retropharynx was measured at four levels: nasopharyngeal, retropalatal, retroglossal, and retroepiglottic in both groups. The mean distance was significantly shorter in the study group than in the control group at all four levels (p < 0.002). We conclude that the most likely diagnosis of a pulsatile mass detected on nasopharyngolaryngoscopy is an aberrant CCA or cervical ICA.

Accuracy and reliability of SPI ProX global positioning system devices for measuring movement demands of team sports

AIM

The aim of this study was to determine the accuracy and reliability of SPI ProX global positioning system (GPS) devices for measuring movement at various speeds and movement patterns as evident in team sport demands.

METHODS

Eleven amateur soccer players performed a 40 m straight sprint test (with 10-20-30 m split times), a zigzag test, 30 m walking, jogging and moderate intensity runs.

RESULTS

Results indicated that the SPI ProX GPS measurements showed acceptable accuracy for all movement patterns for distance (coefficient of variation [CV]=0.14% to 3.73%; 95% ratio limits of agreement [95% ratio LOA]=0.97 x / ÷ 1.09 to 1.00 x / ÷ 1.05) and speed (CV=4.22% to 9.52%; 95%LOA=-0.17 ± 1.70 km h-1 to 2.30 ± 1.17 km h-1) compared with the measured distance and speed determined from timing gates, respectively. Furthermore, acceptable reliability of SPI ProX GPS measures for distance (CV=0.34% to 3.81%; 95%LOA=-0.09 ± 0.23 m to -0.34 ± 2.31 m) and speed (CV=3.19% to 6.95%; 95%LOA=-0.05 ± 3.90 km h-1 to 0.42 ± 3.68 km h-1) were also evident.

CONCLUSION

Whilst SPI ProX GPS devices were within acceptable ranges of reliability, they remained significantly different to criterion measures of team sport movement demands.

CT and MRI findings of the incidental intraosseous lipomatous lesions of the sphenoid bone

BACKGROUND

Intraosseous lipomatous lesions of the sphenoid bone and skull base are increasingly seen and cause a diagnostic challenge. The purpose of this study was to present the imaging findings of 4 patients with incidentally identified intraosseous lipomatous lesions within the sphenoid bone.

METHODS

CT scans and MR images of 4 patients are shown. Macroscopic fat content of the lesions were evaluated by fat-saturated sequences on MRI and by measuring fat density in Hounsfield Units on CT.

RESULTS

The most striking imaging findings of these well-defined lesions were their fat content, preservation of foramina, and absence of cortical destruction.

CONCLUSION

Intraosseous lipomatous lesions are asymptomatic, fat containing, non-touch lesions that should be recognized to prevent unnecessary further investigation, such as biopsy.

Serum uric acid level predicts new-onset atrial fibrillation after coronary artery bypass graft operation

OBJECTIVE

To investigate the association between serum uric acid levels and the risk of incident atrial fibrillation in patients after coronary artery bypass graft (cABG) operation.

PATIENTS AND METHODS

A total of 174 patients undergoing nonemergency coronary artery bypass graft operation were included in the study. Patients with previous atrial arrhythmia or requiring concomitant valve surgery were excluded. We prospectively analyzed 174 patients (mean age: 59.8 years; 109 male and 65 female). The serum uric acid level was determined preoperatively.

RESULTS

After a coronary artery bypass graft operation operation, 35 (20%) patients developed atrial fibrillation. Preoperative uric acid levels were significantly higher in patients who developed atrial fibrillation than in those who did not (7.8 ± 1.1 vs 5 ± 0.9). Using a cutpoint of 6.55, the preoperative level correlated with the appearance of atrial fibrillation with a sensitivity of 91.4% and specificity of 84.2%.

CONCLUSIONS

Serum uric acid level can increase the sensitivity and specificity in predicting atrial fibrillation in patients after CABG operation.

Vena cava superior syndrome developing in a dialysis patient with antithrombin III deficiency following temporary catheterization

Despite being widely reported in patients with neoplasms, vena cava superior (VCS) syndrome linked to thrombosis is a major catheter complication that can be encountered during the use of the hemodialysis catheter. Antithrombin III (AT-III), responsible for a large part of thrombin inactivation capacity in plasma, is the most powerful inhibitor of the thrombosis process. This report describes a case of VCS syndrome developing two weeks following the extraction of a right-sided subclavian catheter in a patient transferred from peritoneal dialysis to hemodialysis for one week due to leakage. The patient presented complaining of swelling and pain in the right arm. At Doppler examination, total thrombosis was observed in the subclavian and internal jugular vein. At advanced examinations due to lack of response to heparin and clinical worsening, VCS and AT-III deficiency were determined. Following thrombolytic therapy with streptokinase, AT-III levels were raised by the administration of plasma, and clinical and radiological stabilization was established by continuing heparin and continuous oral anticoagulant therapy.

Mesenteric fibromatosis

Two rare cases of mesenteric fibromatosis are presented. The first patient had a right upper quadrant mass and colicky abdominal pain. The tumor originated from the mesentery of the colon and it infiltrated the gallbladder, cystic duct, and the liver. The second patient had severe hematemesis and melena. The origin of the tumor, which infiltrated 3/4 part of the stomach, the gastrohepatic ligament, the first part of the duodenum, and the liver could not be determined. In the first patient, partial colectomy and cholecystectomy were performed and the liver lesion was completely excised. The second patient underwent subtotal gastrectomy and left lobectomy of the liver. The first part of the duodenum was excised. Gastrojejunostomy was performed. No recurrence was recorded in either patients during 16 and 13 months follow-up, respectively. In this report, diagnostic aids, differential diagnosis and treatment of this rare disease are discussed.

Retinoblastoma in Turkey: diagnosis and clinical characteristics

Retinoblastoma (RB) is the most frequent malignant intraocular tumor in childhood. Six hundred and thirty-six cases with 831 RB-affected eyes were diagnosed and treated in our specialist center between 1963-1994. The diagnosis was made by histopathologic examination in 617 cases and clinically in 19 cases. Four hundred and forty-one (69.3%) cases were unilateral and 195 (30.7%) were bilateral. Two hundred and sixty-eight (42.1%) were females and 368 (57.9%) were males. The youngest patient was 20 days old and the oldest was 16 years old at the time of diagnosis (mean: 2.2 years). In thirty-four (5.3%) cases, a family history of RB was present. Ten of these cases were unilateral and 24 were bilateral. The most frequent presenting signs were leukocoria (394 cases, 61.9%), buphthalmos (92 cases, 14.5%), and strabismus (68 cases, 10.7%). The referring initial diagnoses were correct in 519 (81.6%) cases and false-negative in 117 (18.4%) cases. The most frequent initial false-negative diagnoses of the referring physicians were buphthalmos (43 cases, 6.8%), endophthalmitis (37 cases, 5.8%), and retinal detachment (12 cases, 1.9%). Apart from these 636 cases, there were 29 false-positive RB diagnoses during the same study period for which enucleation was performed. False-positive diagnoses included endophthalmitis (9 cases), retinal dysplasia (6 cases), retinal detachment (5 cases), vitreous hemorrhage (4 cases), Coats' disease (4 cases), and toxocariasis (one case). Ancillary testing for metastasis was carried out in all cases with newly diagnosed retinoblastoma. Five hundred and ninety-eight (72%) eyes had intraocular disease and 233 (28%) had extraocular spread. Of these 233 RBS, 58 had systemic disease. Fifty-two out of 58 tumors showing systemic involvement had either optic nerve or extrascleral extension at the histopathologic examination of enucleation material. The remaining six eyes had intraocular Class IV-V RB.

Phosphorylation of histones and non-histone nuclear proteins in liver cells stimulated by glucagon and cyclic AMP

Phosphorylation of a characteristic subset of nuclear proteins is increased in rat liver cells stimulated with glucagon. Regulated proteins include histones H1 and H3, an HMG 14-like protein and a previously unidentified 23-kDa basic protein. The effect of glucagon is mimicked by forskolin and exogenous cAMP. Insulin and dexamethasone have no effect. In a cell-free system containing purified hepatocyte nuclei, addition of cAMP-dependent protein kinase results in phosphorylation of histone H3, an HMG 14-like protein and a 23-kDa basic protein similar or identical to the protein phosphorylated in vivo.

Interactions between volume expansion or diuretics and compensatory adaptation

Glomerular filtration rate, urine flow, and Na excretion were measured 3--4 h after unilateral nephrectomy (1/2Nex) or sham operation in unanesthetized rats infused with isotonic saline (0.05--0.75 ml/min) and additionally injected with acetazolamind (20 mg/kg i.p.) or furosemide (5 mg/kg i.p., or 0.2 mg/kg i.v., or 2.0 mg/kg i.v.) or with both agents. Glomerular filtration rate of unilaterally nephrectomized rats averaged 50% of controls. Under all experimental conditions investigated, absolute water and Na excretions were similar in 1/2Nex and sham-operated rats. The fractional excretion (FE) of water and Na was increased 1.5- to 2.2-fold in 1/2Nex animals. The diuretic effects of volume expansion, of the two diuretic agents, and of contralateral nephrectomy consistently were additive. The "compensatory" increase of FESa following contralateral nephrectomy entailed a proportional increase of the diuretic effects of agents given subsequently. Urinary furosemide excretion 15 min after intravenous injection in unilaterally nephrectomized rats was smaller than in controls. The additivity of the diuretic effects of contralateral nephrectomy ("compensatory adaptation") and volume expansion and/or diuretic agents appears to be partly explained by different sites of action.

[Pharmacologic modifications of renal tubular transport]

Possible mechanisms of transport of substances across renal tubular walls and of drug actions influencing these transports are discussed. The precise mechanisms of action of the majority of compounds which enhance or depress transtubular transports is still unknown. Certain inhibitors of transtubular transports may be competitors of the transported substances for tubular membrane carriers. Examples of changes in transtubular transports induced by drugs are reviewed. In the rat, the combined natriuretic and diuretic effects of furosemide and of compensatory adaptation, i.e. removal of the contralateral kidneys a few hours before the experiments, appear to be hyperadditive. The natriuretic and diuretic effects of acetazolamide are similarly enhanced under the conditions of compensatory adaptation. The data suggest that the natriuretic and diuretic effects of compensatory adaptation, on the one hand, and the diuretic agents, on the other hand, are due to different primary effects on the tubules. Bidirectional transports of uric acid across the walls of proximal convoluted tubules have been demonstrated in all species of animals investigated by micropuncture, microperfusion and microinjection. No net movements of uric acid occur across the wall of distal convoluted tubules. In species and under conditions of net reabsorption of uric acid by the whole kidney, the sum of the bidirectional transports across the walls of proximal convoluted tubules always results in pronounced net reabsorption. In species and races of animals characterized by overall tubular secretion of uric acid, the predominant movement in proximal convoluted tubules also tends to be net reabsorption, while the net secretion providing the amounts of uric acid, above the amounts filtered, appearing in the final urine, appears to occur in the straight parts of the proximal tubules. Possible mechanisms of action and micropuncture observations on the sites of actions of probenecid and of pyrazinolic acid, two agents which influence transtubular transports of uric acid, are discussed. The conclusion is reached that agents influencing transtubular uric acid transports probably always act on reabsorptive as well as on secretory transports and that the net result of their action on uric acid excretion may, therefore, vary in different species and under different experimental conditions. Enhancement of the urinary excretion of salicyclic acid by infusion of bicarbonate is a well-known fact. Recent micropuncture experiments indicate that this effect is probably due to either enhanced secretion or depressed reabsorption of salicylates in proximal convoluted tubules rather than on any changes of the rate of transtubular salicylate transports in lower segments of the nephron.