Abnormalities of thirst regulation in patients with chronic renal failure on hemodialysis.

To determine whether thirst mechanisms are altered in nondiabetic patients with chronic renal failure on hemodialysis, 4 patients with an average weight gain between dialysis sessions of more than 5% of dry body weight (group I), 5 patients with less than 3% weight gain (group II), and a group of 6 healthy subjects (group III) were submitted to infusion of hypertonic saline. After infusion the subjects had free access to water. Thirst was evaluated by visual analogue rating scales. Despite similar increments of effective plasma osmolality during saline infusion, patients of group I were thirstier than groups II and III (p less than 0.005 and p less than 0.01, respectively). Changes in thirst ratings were similar in groups II and III. Osmotic thresholds for thirst onset were similar in groups II and III (288.9 +/- 8.5 and 289.8 +/- 3.4 mosm/kg, respectively), but lower in group I (277.6 +/- 7.6 mosm/kg). Nevertheless, great variations were observed in the latter group. Thus, 2 patients showed thresholds for thirst within the normal range, whereas the others had low osmolar thresholds for thirst and baseline plasma osmolalities and high basal thirst scores. During the drinking period, the patients of group I drank more (14.2 +/- 2.8 ml/kg) than those of groups II (5.3 +/- 1.6 ml/kg; p less than 0.02) and III (10.2 +/- 1.6 ml/kg; n.s.) The plasma levels of angiotensin II in uremic patients were higher than in healthy subjects, although there were no differences between groups I and II and no correlation between basal angiotensin II levels and the interdialytic weight gain.(ABSTRACT TRUNCATED AT 250 WORDS)     

A new enzyme-linked fluorescence assay (ELFA) for use with peroxidase-antibody conjugates: a comparison with ELISA for the quantitation of IgM antibodies to hepatitis B core antigen

A new enzyme-linked fluorescence assay (ELFA) suitable for use with peroxidase-antibody conjugates is described. The substrate for the assay is p-hydroxyphenylacetic acid, the fluorescent product of which is stable and unaffected by light. The assay compared favourably with a standard ELISA for the quantitation of IgM antibodies to hepatitis B core antigen.     

Cerebral haemodynamics in preterm infants after exposure to dexamethasone

AIM—To determine changes in brain haemodynamics produced by dexamethasone; to evaluate the pathophysiological conditions involved in the effect of dexamethasone.METHODS—A prospective study was made of 12 ventilated preterm infants who received dexamethasone (0.25 mg/kg/12 hours) for ongoing chronic lung disease or extubation failure. Cerebral blood flow (CBF), absolute cerebral blood volume (CBV), and cerebral blood volume changes (ΔCBV) were estimated by near infrared spectroscopy, before and 10, 30, 60, 120, 180 and 240 minutes after the first, third, and fifth doses of dexamethasone. All patients were monitored continuously using pulse oximetry, transcutaneous blood gases, and blood pressure.RESULTS—There were significant short term changes in ΔCBV on each day of the study; ΔCBV increased significantly at 240 minutes compared with values before the first dose, and from 120 minutes onward during the third and fifth doses. However, mean CBV values averaged over 240 minutes after the first, third, and fifth doses did not vary. Mean CBF values averaged over 240 minutes increased progressively up to the fifth dose (significant differences between the first and fifth dose). The short term changes in CBF consisted of a significant increase 60 minutes after dexamethasone administration compared with the before and 10 minute values in every study. Blood pressure was significantly higher in the third and fifth doses than in the first dose. Blood pressure showed no short term changes. There was no correlation between CBF and blood pressure changes. TcPCO₂ (transcutaneous PCO₂) decreased significantly throughout the study period, with the average mean value in the fifth dose significantly lower than in the first dose. Nevertheless, no short term changes in TcPCO₂ were observed.CONCLUSIONS—Postnatal systemic dexamethasone administration produced significant changes in cerebral haemodynamics that seemed to be related to both a direct effect on regional vessel walls and the cumulative effect of dexamethasone.     

Alloplastic bladder substitution: are we making progress?

Radical cystectomy with lymphadenectomy and urinary diversion is the gold standard treatment for bladder cancer in organ-confined muscle-invasive disease and selected patients who have high-grade non-muscle-invasive disease or are non-responders to BCG. The main and most morbid complications of this challenging surgery are related to the use of bowel for urinary tract reconstruction. For this reason, many past projects were devoted to finding an alternative to the use of bowel. The aim of this review is to provide a summary of the evolution of alloplastic bladder substitution. A comprehensive review of the literature was performed using the Medline National Library of Medicine database and Google Scholar. Keywords used were cystectomy and intestine/bowel, replacement, bladder substitution, organ replacement, artificial bladder, alloplastic material, biomaterial, and tissue engineering. Various prostheses have been proposed for replacement of the urinary bladder, silicone being the most frequently used material. The first published model of an alloplastic bladder was described by Bogash et al. in late 1959, while the last, in 1996, was suggested by Rohrmann. Interprofessional collaboration, recent advances in technology, and tissue engineering may help in developing suitable bladder prostheses. Urologists as well as engineers and the industry need to give this matter serious attention.     

Skeletal muscle pathways of contraction-enhanced glucose uptake

Muscle contraction acutely increases glucose transport in both healthy and type 2 diabetic individuals. Since glucose uptake during muscle contraction has been observed in the absence of insulin, the existence of an insulin-independent pathway has been suggested to explain this phenomenon. However, the exact mechanism behind the translocation of GLUT4 vesicles through the sarcolemma during muscle contraction is still unknown. Some substances, such as AMPK and calcium activated proteins, have been suggested as potential mediators but the exact mechanisms of their involvement remain to be elucidated. A hypothetical convergence point between the insulin cascade and the potential pathways triggered by muscle contraction has been suggested. Therefore, the earliest concept that two different routes exist in skeletal muscle has been progressively modified to the notion that glucose uptake is induced by muscle contraction via components of the insulin pathway. With further consideration, increased glucose uptake and enhanced insulin sensitivity observed during/after exercise might be explained by a metabolic- and calcium-dependent activation of several intermediate molecules of the insulin cascade. This paper aimed to review the literature in order to examine in detail these concepts behind muscle contraction-induced glucose uptake.     

Impact of Delta Hemoglobin on Provider Transfusion Practices and Post-operative Morbidity Among Patients Undergoing Liver and Pancreatic Surgery

Background

Delta hemoglobin (ΔHb) is defined as the difference between the preoperative Hb and the lowest post-operative Hb level. We sought to define the impact of ΔHb relative to nadir Hb levels on the likelihood of transfusion, as well as characterize the impact of ΔHb and nadir Hb on morbidity among a large cohort of patients undergoing complex hepatopancreatobiliary (HPB) surgery.

Methods

Patients who underwent pancreatic or hepatic resection between January 1, 2009 and June 30, 2015 at Johns Hopkins Hospital were identified. Data on the perioperative ΔHb, nadir Hb, as well as blood utilization were obtained and analyzed. Multivariable logistic regression models were used to identify the factors associated with ΔHb and the impact of ΔHb on perioperative morbidity. A Bayesian model was used to evaluate the correlation of ΔHb and nadir Hb with the likelihood of transfusion, as well as the impact on morbidity.

Results

A total of 4363 patients who underwent hepatobiliary (n?=?2200, 50.4 %) or pancreatic (n?=?2163, 49.6 %) surgery were identified. More than one quarter of patients received at least one unit of packed red blood cells (PRBC) (n?=?1187, 27.2 %). The median nadir Hb was 9.2 (IQR 7.9–10.5)?g/dL resulting in an average ΔHb of 3.4 mg/dL (IQR 2.2–4.7) corresponding to 26.3 %. Both ΔHb and nadir Hb strongly influenced provider behavior with regards to use of transfusion. Among patients with the same nadir Hb, ΔHb was strongly associated with use of transfusion; among patients who had a nadir Hb ≤6 g/dL, the use of transfusion was only 17.9 % when the ΔHb?=?10 % versus 49.1 and 80.9 % when the ΔHb was 30 or 50 %, respectively. Perioperative complications occurred in 584 patients (13.4 %) and were more common among patients with a higher value of ΔHb, as well as patients who received PRBC (both P?<?0.001).

Conclusions

The combination of the Hb trigger with ΔHb was associated with transfusion practices among providers. Larger ΔHb values, as well as receipt of transfusion, were strongly associated with risk of perioperative complication following HPB surgery.

     

Thyroid disease in primary Sjögren syndrome. Study in a series of 160 patients

We studied 160 consecutive patients (147 female and 13 male) with primary Sj?gren syndrome (SS) to determine the prevalence and clinical significance of thyroid disease in a large series of patients with primary SS from our unit and to compare the prevalence and significance with those in 75 individuals without SS from a primary care center. Serum levels of thyroid hormones (free thyroxine, triiodothyronine, and thyroid-stimulating hormone) and autoantibodies against thyroglobulin (TgAb) and thyroid peroxidase (TPOAb) were measured in all SS patients and in 75 control patients. Fifty-eight (36%) of the 160 patients with primary SS had evidence of thyroid disease. Autoimmune thyroid disease (ATD) was diagnosed in 32 (20%) patients and nonautoimmune thyroid disease (NATD) in 26 (16%). No significant differences were found when these prevalences were compared with those in control patients. On the other hand, comparing those patients with altered hormonal profiles, patients with NATD showed mainly hyperthyroidism (10/17, 59% versus 2/20, 10% in patients with ATD, p = 0.001). Finally, when clinical and immunologic manifestations of SS were analyzed in patients with and without thyroid disease, respectively, we found that patients with thyroid disease had a higher prevalence of female gender (98% versus 88%, p = 0.03), antiparietal cell autoantibodies (33% versus 12%, p = 0.002), TgAb (30% versus 5%, p < 0.001), and TPOAb (40% versus 5%, p < 0.001). In conclusion, thyroid disease occurred in more than one-third of patients with primary SS; the main cause was ATD, which was present in 20% of the patients studied. We note that no significant differences were observed when the prevalence of thyroid disease (either ATD or NATD) was compared with that in a control group of similar age and gender. Our results indicate that middle-aged women (with or without SS) should be screened periodically for thyroid function.