Thoracic lymph drainage in the dog: evaluation of a new model

A new model for selective sampling of thoracic lymph flow (TLF) and abdominal lymph flow (TDA) in the dog was assessed to ascertain whether there were extrathoracic contributions of lymph to the TLF. Inflating a right atrial balloon in 4 dogs and a left atrial balloon in 2 dogs indicated good separation between TLF and TDA. Data on total lymph protein and albumin clearance before and after oleic acid induced pulmonary oedema in an additional 5 dogs indicated that TLF and TDA drained two differing regions. Our data demonstrate that this lymph preparation provides a sample of thoracic lymph flow with no major extrathoracic lymph contamination. We also propose an alternative method to test for extrathoracic contributions to thoracic lymph, by the application of positive end-expiratory pressure, thereby replacing right atrial balloon inflation.

Net fluid leakage (LN) in experimental pulmonary oedema in the dog

Net fluid leakage (LN) from the intravascular to the extravascular pulmonary space was estimated in anaesthetised dogs after injection of oleic acid (OA) (n = 8), or after hydrostatic pressure elevation by inflation of a left atrial balloon (n = 5). LN was calculated as the sum of: (i) rate of change in extravascular lung water (delta EVLW), (ii) thoracic lymph flow, and (iii) pleural fluid formation per time unit. Pleural fluid formation was measured in five dogs with hydrostatic or OA induced pulmonary oedema and was 1.8 +/- 0.9 ml/kg/h. In OA-induced pulmonary oedema, LN increased to a peak of 9.2 ml/kg/h within 2 h after OA injection. Thereafter LN fell and was 2-4 ml/kg/h during the succeeding 2-4 h. During hydrostatic pulmonary oedema LN was increased to as much as 13 ml/kg/h, but it became negative, -5 to -8 ml/kg/h (reabsorption of extravascular fluid) as soon as pulmonary vascular pressures returned to normal following deflation of the left atrial balloon. We conclude that in both forms of oedema there is an initial rapid leakage. In OA-induced oedema this leakage continues, although at a slower rate, whereas in hydrostatic oedema there is a considerable net fluid absorption from the pulmonary extravascular to the intravascular space as soon as vascular pressures are brought to normal levels.

Guidelines for evaluation of reagent strips. Exemplified by analysis of urine albumin and glucose concentration using visually read reagent strips. International Federation of Clinical Chemistry, Scientific Division

Reagent strips are frequently used in the practice of laboratory medicine as well as outside the professional laboratories. In the present report, a scheme is presented which allows a reproducible description of the performance of reagent strips. This is exemplified using strips intended for estimation of urinary albumin and glucose. Experimental conditions that are particularly important for these components are given. Suitable and necessary items which should be included in the protocol presenting results of an evaluation are listed. The guidelines might have general applicability in evaluation and description of tests with a limited number of possible results.

[Effect of beta blockers on retinal hemodynamics. A double-blind study in healthy probands]

In a randomized double-blind study the effect of topically applied Timolol (Chibro-Timoptol 0.5%) on the retinal circulation was investigated. In order to quantify the retinal hemodynamics 20 healthy volunteers were examined twice using video fluorescein angiography. The arteriovenous passage time (AVP) and the dye bolus velocity (MDV) were quantified using an image-analyzing system. Following administration of Timolol, IOP decreased from 14.5 +/- 1.9 mm Hg to 9.4 +/- 1.7 mm Hg (P less than 0.010). The study also showed that there was a significant reduction in AVP from 1.75 +/- 0.5 s to 1.56 +/- 0.3 s (P less than 0.05) and an increase in MDV following local application of Timolol. No effect on systemic blood pressure or pulse rate was observed. The results indicate that in addition to its pressure-lowering effect, timolol also leads to increased retinal perfusion.

Nitrogen and phosphorus release from decomposing litter in relation to the disappearance of lignin

Concentrations of nitrogen, phosphorus, and acid insoluble substances were followed in decomposing forest foliage litters in some different forest biomes and in a laboratory study. In all cases, the concentration of these substances increased linearly with litter mass loss. In contrast, absolute amounts of these materials in the litter began decreasing at some point during decay, usually following a period of absolute increase (i.e., immobilization of nutrients or humification for acid insoluble substances). The point during decomposition at which a net release (net disappearance) of a substance began (point for maximum amount), was estimated using the linear relations between concentrations of the substance and accumulated litter mass loss. In addition, the concentrations of acid insoluble substances at maximum absolute amounts of nitrogen and phosphorus were estimated. The results indicate that the points in decay at which a net release of nitrogen and phosphorus began were linearly related to one another and to the onset of acid insoluble substance disappearance. In all litters studied, net release of nitrogen and phosphorus began after a net release of the recalcitrant acid insoluble substance fraction had begun. The relationship between the onset of acid insoluble substance loss and nitrogen and phosphorus release differed between deciduous and coniferous foliage litters. Key words: decomposition, litter, nitrogen, phosphorus, lignin, nitrogen release, phosphorus release.

Lipid lowering in severe familial hypercholesterolaemia: efficacy and safety of a new regenerating system for selective apheresis of apolipoprotein B-containing lipoproteins

Preliminary experience of the efficacy and safety of a new regenerating system for selective extracorporeal removal of apolipoprotein B-containing lipoproteins is described. Four patients with familial hyperlipoproteinaemia were studied on 10 occasions. A system of two, parallel, dextran sulphate cellulose columns was used, and plasma was processed continuously by passage through one of the columns while the other was being regenerated. With this procedure, reductions of very low density and low density lipoprotein cholesterol levels by 73 and 43%, respectively, could be achieved after treatment for 2.5-3 h (1000-3200 ml of plasma volume). No clinically relevant changes in the concentrations of other plasma proteins, including high density lipoproteins, were observed, and the treatment was well tolerated. We conclude that continuous selective apolipoprotein B apheresis is a safe and efficient lipid-lowering procedure which may be used both for metabolic investigations and for studies on possible regression of atherosclerosis.

Psychosocial dimensions of epilepsy: a review of the literature

The literature on psychosocial dimensions of epilepsy has been reviewed utilizing the framework developed by Dodrill et al. (Epilepsia 1980; 21:123-35). Factors considered were family background, emotional adjustment, interpersonal adjustment, vocational adjustment, financial status, adjustment to seizures, and medicine and medical management. The published studies highlighted a number of issues and sometimes rendered varying and contradictory conclusions. In general, epilepsy fosters certain reactions in family members. If negative, these reactions may be detrimental to the person with epilepsy. The association between specific emotional adjustment factors and epilepsy is not conclusive. Studies have been published which support as well as refute this association. Studies indicate that persons with epilepsy experience lower rates of marriage and more sexual difficulties than do nonepileptic persons. Studies report greater unemployment and underemployment in epileptic persons than in the population at large. Studies suggest that some persons with epilepsy manifest an attitude of nonacceptance of self. Some are reluctant to disclose their disability to others. The studies also indicate the presence of a discriminatory attitude by some nonepileptic persons toward epileptic persons. Several factors are associated with successful medical management of epilepsy. The emphasis in research studies with regard to psychosocial aspects of epilepsy focuses predominantly on individual deficiencies rather than on strengths and abilities.

Importance of correct handling of samples for the results of blood gas analysis

The importance of correct handling of samples for blood gas analysis was studied in 100 patients. Sixty minutes storage in iced water lowered pH by 0.02 pH-units. Storage at room temperature caused considerable changes in PCO2 and PO2 (+0.45 kPa and -1.05 kPa). Air bubbles in the syringes increased PO2 if not expelled within 30 s. Thirty minutes storage with air trapped inside the syringe caused an increase in PO2 of 1.8 kPa and a decrease in PCO2 of 0.16 kPa. The use of plastic syringes induced significant changes in PCO2 and PO2, of which the latter (+1.0 kPa) may be clinically significant. The findings indicate that sample collection and storage must be guarded by strict rules in order to avoid false results.

DDAVP test for renal concentration capacity. Age-related reference intervals

The effect of different levels of fluid intake on the renal concentration test was evaluated. Maximal urinary osmolality did not significantly differ whether strict fluid restriction was kept or not. One side effect, namely headache, seemed more frequent after fluid deprivation than after a more liberal fluid intake. We suggest a practical approach to the performance of the urinary concentration test with DDAVP. The maximal urinary concentration after a single subcutaneous injection of 4 micrograms DDAVP was determined in 212 healthy adults aged 20 to 80 years. A significant decline with age was found in maximum urinary concentration, mean values ranging from 982 mOsm/kg at 20 years to 823 mOsm/kg at 80 years. References are given for different ages which render the test useful in adult patients.

Subcutaneous and intranasal administration of 1-deamino-8-d-arginine vasopressin in the assessment of renal concentration capacity

Maximum urine concentration capacity was studied in healthy adults using different routes and doses of administration of 1-deamino-8-d-arginine vasopressin (DDAVP)-desmopressin. Plasma levels of DDAVP showed a dose-dependent increase after the subcutaneous but not after the intranasal administration. The effect on urine osmolality was similar but more prolonged after the subcutaneous as compared to the intranasal route. We conclude that subcutaneous injection is a simple and reliable way of administering DDAVP. A dose of 4 micrograms in adults is optimum diagnostically and it corresponds to 20-40 micrograms administered intranasally.

The effects of hydraulic resistance strength training in pre-pubertal males

In order to examine the effectiveness and safety of hydraulic resistance strength training in young males, 26 pre-pubertal males (mean age = 8.2 +/- 1.3 yr) completed a 14-wk strength training study. Subjects were evaluated before and after the 14-wk experimental period for pubertal state (Tanner's sexual maturity rating, serum testosterone, and serum dihydroepiandrosterone sulfate). Effectiveness of the strength training program was determined by measuring pre-post differences in: isokinetic strength for flexion and extension at the knee and elbow joints at two speeds (30 degrees and 90 degrees X s-1) (KIN COM, Chattecx, Inc., Chattanooga, TN), flexibility, standing long jump, vertical jump, body composition parameters, maximal oxygen consumption, and creatinine phosphokinase. Safety of strength training was assessed by biphasic musculoskeletal scintigraphy before and after the program and by physician evaluation of complaints by subjects. Strength training subjects (N = 16) participated in a 45 min/session, 3 session/wk, 14-wk supervised strength training program with an attendance rate of 91.5%. Participants performed concentric work using hydraulic resistance equipment (Hydra-Fitness Industries, Belton, TX). Eccentric work was not performed. Control subjects (N = 10) did not strength train but did participate in sport activities and activities of daily living. Results indicated that strength training subjects increased isokinetic strength as a result of strength training (average concentric work/repetition increases by 18.5 to 36.6% for the eight motions tested; torque scores over the first 90% of the range of motion increases by 13.1 to 45.1% for the eight motions tested). These changes were significantly greater than changes seen in the control group (P less than 0.05). Strength training subjects also demonstrated significant improvements (as compared to control subjects) in vertical jump (+10.4%), flexibility (+8.4%), and maximal oxygen consumption [+19.4% (l X min-1), +13.8% (ml X kg X min-1)] after the experimental period. Musculoskeletal scintigraphy revealed no evidence of damage to epiphyses, bone, or muscle as a result of strength training. Only one strength training-related injury was reported (left shoulder pain, 3 strength training sessions missed). In contrast, six strength training subjects sustained injuries during activities of daily living, resulting in 47 missed strength training sessions. It was concluded that, in the short term, supervised concentric strength training using hydraulic resistance equipment is safe and effective in pre-pubertal boys.

Ascorbate interference in the estimation of urinary glucose by test strips

Currently used test strip methods for the detection of glucose in urine are influenced by ascorbate and may thus give false negative results, e.g. in screening for diabetes. Six different test strips for urine glucose were evaluated for interference by ascorbate in vitro. Interference by ascorbate varied markedly, being highest at low glucose concentrations. Interference coefficients for the individual tests were calculated to serve as an approximate index of interference by ascorbate. A new test (BM 33.071, Boehringer Mannheim GmbH, currently used in Combur-9-Test/Chemstrip-9 and other multiple test strips of Boehringer Mannheim) was clearly much less influenced as no urine containing 5.5 mmol/l glucose was read as negative even at very high ascorbate concentration. Readability of test strips differed due to patchy colour reactions. Precision was good within-test strip and within-urine but markedly less between urines.

Cholestasis of pregnancy. Clinical and laboratory studies

A prospective study was made of clinical symptoms, liver function and pregnancy prognosis in women with cholestasis of pregnancy (CP). We used several positive and negative criteria to allow a clinical definition of CP as itching limited to time of pregnancy with or without laboratory evidence of liver dysfunction. The incidence during 1971-74 was 1.5% (100/6798 women) and lower during 1980-82 (52/5441 = 1.0%). One hundred consecutive pregnant women without itching were used as clinical controls. The incidence of CP showed a distinct seasonal variation, culminating in November. Women with CP had often had itching during previous pregnancies and during use of contraceptive pills and described anamnestically itching in mother and sisters. Laboratory data in CP were compared with reference intervals for healthy pregnant women. Serum enzyme levels were significantly increased for serum alkaline phosphatase, 5-nucleotidase, aspartate aminotransferase and alanine aminotransferase in the second and especially in the third trimester. The enzyme distribution was often markedly skewed to the right, i.e. some patients reacted more than others. Most patients with cholestasis only had itching without pronounced abnormalities in laboratory data. This mild form of CP was associated with a good prognosis for both mother and child.

Temporal variation of litter decomposition in relation to simulated soil climate. Long-term decomposition in a Scots pine forest. V

Decomposition of Scots pine needle litter was studied in a Scots pine forest in central Sweden. A 6-year series with annual incubations of needle litter was used to analyse the climatic influence on the process. The original litter was of similar chemical properties between years and each year new litter was incubated, in the same way, in the autumn. Sampling took place at time intervals ranging from 1 month to 1 year. Soil climate variables such as temperature and water contents and tensions were calculated with a soil water and heat model from standard meteorological data. Decomposition rates from periods longer than 145 days were correlated with different soil climatic factors. The responses for the 1st and 2nd incubation years were not significantly different, but higher coefficients of determination (r2) were found for the 2nd year. Estimated actual evapotranspiration or soil temperature explained temporal variation of decomposition to about 70%; soil water content only or soil water tension only explained 90%. When moisture and temperature were combined, 95 and 99% of the variation could be explained for the 1st and 2nd year, respectively. When time periods down to 1 month were included, very poor fits were found with the same climate response functions. However, the relationships were improved by an inertia function which indicated a time lag of 2–3 months between soil climate and the response in decomposition rate.