Examination of the recommended safe and unsafe zone for placement of surgical instruments in thoracentesis and video-assisted thoracic surgery: a cadaveric study.

BACKGROUND: Thoracentesis and video-assisted thoracic surgery procedures can result in haemorrhage as a consequence of severing the collateral branches of the posterior intercostal artery. These branches have been shown to be most common in the 5th intercostal space (ICS). Tortuosity has been shown to be especially prevalent nearer to midline. A group of investigators have recommended the 4th and 7th ICS, 120 mm lateral to midline as a safe zone, least likely to hit branches when cutting into the ICS. The present study aimed to investigate that safe zone as a better entry points for procedures. In addition, investigation of the least safe 5th ICS was also performed. MATERIALS AND METHODS: A total of 56 embalmed human cadavers were selected for the study. With the cadavers laid prone, 2 cm incisions were made at the 4th, 5th and 7th ICS, 120 mm lateral to midline bilaterally. The cadavers were then placed supine and the incisions were dissected. Careful attention was paid to identify if any collateral branches were cut. RESULTS: After thorough dissection of the 4th, 5th and 7th ICS incision sites, it was shown that damage to the 5th intercostal was seen most frequently. CONCLUSIONS: Based on this cadaveric study, a 2 cm incision at the 4th, 5th and 7th ICS 120 mm lateral from midline resulted in the most damage at the level of the 5th ICS. The 4th ICS had the least damage seen. Therefore, it is recommended that insertion should be placed at the level of the 4th ICS bilaterally.

Annular pancreas causing pyloric stenosis in a 66-year-old patient treated with gastrojejunostomy: a case report.

Annular pancreas is defined by a ring of pancreatic tissue encircling the descending portion of the duodenum. It is exceptionally rare in adults and commonly diagnosed during the investigation of symptoms arising due to its complications. Treatment usually involves the surgical correction with a duodenoduodenostomy, gastrojejunostomy or duodenojejunostomy. We discuss the case of a 66-year-old male patient who presented with symptoms of gastric outlet obstruction and was found to have an annular pancreas encircling the pylorus and the first and second portions of the duodenum and was treated by performing a gastrojejunostomy. Upper gastrointestinal series, computerized tomography (CT) scans, and magnetic resonance cholangeopancreatographys can all be used for preoperative diagnosis; however, endoscopic retrograde cholangiopancreatography (ERCP) is the diagnostic modality of choice. Nonetheless, many patients may only be diagnosed intraoperatively, especially those who cannot undergo an ERCP due to stenosis proximal to the duodenum or patients in whom the annulus may not be visible on CT scan.

Urea production and salvage during pregnancy in normal Jamaican women.

The pattern of aggregate nitrogen demand during pregnancy and the fetal and maternal components are unclear. Excess demand enhances efficiency of nitrogen utilization. Urea salvage contributes to enhanced efficiency. Dietary protein intake, urea production, and salvage of urea nitrogen were measured in eight nonpregnant control subjects, and trimesterly in nine pregnant women. Production was measured after prime-intermittent intravenous doses of [15N 15N]-urea by dilution of label in urinary urea. Dietary protein intake was greater in trimester 1 than in nonpregnant women (167 +/- 36 vs 224 +/- 60 mg N.kg-1.d-1), and increased further in trimester 2 (266 +/- 59 mg N.kg-1.d-1). Urea production was not higher during pregnancy. Despite higher protein intake, urea salvage was higher in pregnancy (40 +/- 24 nonpregnant vs 77 +/- 23, 61 +/- 31, and 51 +/- 12 mg N.kg-1.d-1). Therefore, the demand-supply gap for nitrogen was greatest early in pregnancy when fetoplacental growth is slowest, and implies heightened maternal demand.

Protein turnover and thermogenesis in response to high-protein and high-carbohydrate feeding in men.

The rates of energy expenditure and wholebody protein turnover were determined during a 9-h period in a group of seven men while they received hourly isocaloric meals of high-protein (HP) or high-carbohydrate (HC) content. Their responses to feeding were compared with those to a short period of fasting (15-24 h). The 9-h thermic response to the repeated feeding of HP meals was found to be greater than that to the HC meals (9.6 +/- 0.6% vs 5.7 +/- 0.4% of the energy intake, respectively, means +/- SEM, p less than 0.01). The rate of whole-body nitrogen turnover over 9 h increased from 17.6 +/- 2.2 g on the fasting day to 27.4 +/- 1.4 g during HC feeding (NS) and there was a further increase to 58.2 +/- 5.3 g resulting from HP feeding (p less than 0.001). By using theoretical estimates (based upon ATP requirements) of the metabolic cost of protein synthesis, 36 +/- 9% of the thermic response to HC feeding and 68 +/- 3% of the response to HP feeding could be accounted for by the increases in protein synthesis compared with the fasting state.

Stool culture: are you getting value for money?

AIMS: To assess the best medium for primary isolation of enteric pathogens; to determine the need for a second primary culture medium; and to gather information on stool culture media used in 20 other randomly selected laboratories. METHODS: Specimens were cultured on desoxycholate citrate agar (DCA), Hektoen enteric agar (Hektoen), and xylose lysine deoxycholate agar (XLD). Non-lactose fermenters were screened with Rapidec Z (bio-Mérieux) and identified with API 10S (bio-Mérieux) where appropriate. Shigellas were identified with API 20E (bio-Mérieux) and serology, and salmonellas biochemically and by serology. A telephone survey was carried out to enquire into different culture practices and whether they had been evaluated for cost effectiveness. RESULTS: The isolation rate of enteric pathogens on primary stool culture media was 97% on DCA, 88% on XLD, and 76% on Hektoen. Seventeen of 18 shigellas grew on DCA, 13 of 18 on XLD, and 14 of 18 on Hektoen. DCA missed one Salmonella, XLD three, and Hektoen 13. XLD and Hektoen both missed Yersinia enterocolitica. The telephone survey revealed a diverse range of both primary and subculture plates. There was little evidence of evaluation of stool media, but firm personal convictions concerning the advantages and disadvantages of each type of medium at each stage of culture. CONCLUSIONS: DCA performed best and was the most cost effective of the three media. Neither XLD nor Hektoen were satisfactory as primary culture media because they grew fewer pathogens than DCA.

Enteric media: pre-poured or in-house?

AIMS: (1) To evaluate the performance of in-house and pre-poured commercially available enteric agar by challenge with a large number of positive clinical specimens. (2) To set the standard (critical independent evaluation) which new products should reach. (3) To publish this information, so that others can make informed decisions about enteric media. METHODS: Thirteen media of anonymous source were challenged with "known" positive stool samples. RESULTS: In-house desoxycholate citrate agar performed best for overall pathogen isolation rates, for shigella isolation rates, and for most pathogens available on primary culture. CONCLUSIONS: Desoxycholate citrate agar made by our own laboratory yielded the most pathogens and proved the most effective.

Urea kinetics: effect of severely restricted dietary intakes on urea hydrolysis.

Urea kinetics (urea-N production-P, excretion-E, hydrolysis-H, recycling-R and retention-S) were measured in 7 healthy adults consuming a standard diet compared with 4 fasted for 24 and/or 96 h, using primed/intermittent doses of [(15)N (15)N]-urea and mass spectrometry. Standard values were P = 196, E = 132, H = 65, R = 13 and S = 51, mgN/kg/day. After 24 h fasting all urea kinetics were reduced, and P and H were significantly reduced compared with the standard diet (p < 0.01 and < 0.05 respectively). After 96 h fasting, urea kinetics returned to standard values (P = 187, E = 136, H = 51, R =13 and S = 38, mgN/kg/day), although nitrogen intake was significantly lower (p < 0.001). Relative urea excretion (E/P) was 67%, standard diet, and 75% after fasting. Consequently H/P was slightly reduced from 33 to 25%. S/P was 26%, standard diet, 15% after 24 h and 20% after 96 h fasting, suggesting increased urea-N retention with prolonged fasting. These results imply a slight temporary shift towards increased nitrogen excretion at 24 h and subsequent return to the kinetics of the fed state after 96 h. Urea-N retention increases with prolonged fasting.

Urinary 5-L-oxoproline (pyroglutamic acid) excretion is greater in infants in Jamaica than in infants in England.

OBJECTIVE: To determine the pattern of excretion in urine of 5-L-oxoproline, as a measure of glycine status, during the first six weeks of life in Jamaican infants. DESIGN: Spot samples of urine were collected from term and preterm infants at birth and longitudinally to four weeks of age, or at six weeks of age. 5-L-oxoproline was isolated by column chromatography and hydrolysed to L-glutamic acid, which was measured enzymatically and the results expressed relative to creatinine excretion. SETTING: Maternity wards and postnatal clinic of the University Hospital of the West Indies. SUBJECTS: African-Caribbean infants, 19 term and 21 preterm, from birth to four weeks of age, and 79 term infants at six weeks of age. RESULTS: There were no differences between term and preterm infants. Excretion of 5-L-oxoproline increased progressively from birth, 141 mumol/mmol creatinine, to 270 mumol/mmol creatinine at four weeks of age. At six weeks of age, excretion was significantly greater than at birth or four weeks of age, 525 mumol/mmol creatinine. Compared with infants born in England, the excretion of 5-L-oxoproline was not different at birth, but was significantly greater in Jamaican infants at six weeks of age. CONCLUSIONS: Glycine status, indicated by increased excretion of 5-L-oxoproline, is marginal in Jamaican infants at six weeks of age, and this possibly reflects a limitation in the endogenous biosynthesis of glycine due to a dietary limitation of folate or vitamin B-12.

Urea kinetics varies in Jamaican women and men in relation to adiposity, lean body mass and protein intake.

OBJECTIVE: We have measured urea kinetics in normal adult men and women of different body composition to determine whether adiposity is associated with differences in the rate of urea production or endogenous urea hydrolysis. DESIGN: Urea kinetics were determined from the excretion of [15N15N]urea in urine over a period of 48 h following a single oral dose of [15N15N]urea, in nine lean and nine obese women and in seven light and seven heavy males while they were consuming their habitual diets. Urinary 5-L-oxoproline was measured as an index of glycine metabolic status. SETTING: The studies were carried out in the research ward of the Tropical Metabolism Research Unit, University of the West Indies. RESULTS: Successful studies were completed in eight obese and five lean women and in six heavy and five light men. When compared with lean women, in obese women the rate of urea production and hydrolysis was significantly greater and this difference could not be accounted for by the greater fat-free mass alone, and was in part associated directly with the increase in fat mass. The rate of urea production and hydrolysis was greater in heavy men than in light men, a difference which was attributed to an increase in dietary protein. In obese women and heavy men there was a significantly higher rate of excretion of 5-L-oxoproline in urine when compared with lean women and lean men respectively. CONCLUSION: This paper highlights the difficulty in identifying an appropriate reference with which to express results in people of different body composition. In obese women urea production and the hydrolysis of urea are increased, in part related to the increased fat-free mass, but also related to the increased fat mass itself. In obese women and men on high protein diets the greater rate of hydrolysis urea may be a reflection of an increased demand for the synthesis of non-essential amino acids, especially glycine.

Urinary excretion of 5-L-oxoproline (pyroglutamic acid) during early life in term and preterm infants.

Urinary 5-L-oxoproline was measured in term and preterm infants from shortly after birth until 6 weeks of postnatal age to determine their ability to synthesise glycine. In term infants the excretion was five to 10 times that seen in normal adults, increasing from 105 mumol/mmol creatinine in the first 72 hours after birth to 170 mumol/mmol creatinine at 6 weeks of age. There was a significant inverse linear correlation between the excretion of 5-L-oxoproline and length of gestation or birthweight. By 6 weeks of age there was no longer a significant difference in 5-L-oxoproline between term and preterm infants. There was no difference in the excretion of 5-L-oxoproline between boys and girls, or between infants fed on human milk or an artificial formula. If, in part, variability in the excretion of 5-L-oxoproline is determined by the extent to which the endogenous formation of glycine is adequate, then glycine formation may be marginal during early life, more so in preterm than in term infants, providing additional evidence that glycine is a conditionally essential amino acid in the neonate.

Training does not affect protein turnover in pre- and early pubertal female gymnasts.

This study compared protein turnover in ten young female gymnasts [10.3 (0.5) years] engaged in regular intense physical training with ten age-matched controls [9.4 (0.6) years)]. Nitrogen flux ( Q), protein synthesis (PS), protein degradation (PD) and net protein turnover (NPB = PS-PD) were measured following a single oral dose of [(15)N]-glycine. The habitual dietary intake of each subject was assessed using a 7-day food record, with food portions being weighed before ingestion. The gymnasts had a low total energy intake which was unbalanced in the proportions of lipid, carbohydrate and protein. Protein flux was 7.19 (0.35) g.kg(-1).day(-1) in the gymnasts and 7.53 (0.81) g.kg(-1).day(-1) in the controls; protein synthesis was 6.06 (0.27) g.kg(-1).day(-1 )in the gymnasts and 6.53 (0.74) g.kg(-1).day(-1) in the controls; protein degradation was 5.45 (0.38) g.kg(-1).day(-1) in the gymnasts and 5.27 (0.74) g.kg(-1).day(-1) in the controls. All data are presented as means and standard errors of the mean (SEM). There were no statistical differences for protein flux, protein synthesis or protein degradation between the two groups. However, NPB was lower (-14%) in the trained gymnasts than in the control group ( P <0.05), which might be explained by a greater protein ingestion in the control group on the day of the protocol ( P <0.05). These results show that in pre- and early pubertal female gymnasts intense training does not exert a demonstrable effect on protein turnover.

Urea kinetics in healthy women during normal pregnancy.

Urea kinetics were measured in normal women aged 22-34 years at weeks 16, 24 and 32 on either their habitual protein intake (HABIT) or a controlled intake of 60 g protein/d (CONTROL), using primed-intermittent oral doses of [15N15N]urea and measurement of plateau enrichment in urinary urea over 18 h (ID) or a single oral dose of [15N15N]urea and measurement of enrichment of urea in urine over the following 48 h (SD). The intake of protein during HABIT-ID (80 g/d) was greater than that on HABIT-SD (71 g/d); urea production as a percentage of intake was significantly greater at week 16 for HABIT-ID than HABIT-SD, whereas urea hydrolysis at week 16 was greater for HABIT-SD than HABIT-ID and urea excretion at week 32 was greater for HABIT-ID than HABIT-SD. The combined results for HABIT-ID and HABIT-SD showed a significant reduction in urea production at week 32 compared with week 24. Urea excretion decreased significantly from week 16 to week 24 with no further decrease to week 32 and urea hydrolysis was significantly greater at week 24 than either week 16 or week 32. Compared with HABIT, on CONTROL there was a decrease in urea production at week 16, and urea excretion was significantly reduced at week 16. For all time periods urea production was closely related to the sum of intake plus hydrolysis. Hydrolysis was greatest at week 24 and closely related to urea production. There was a significant inverse linear relationship overall for hydrolysis as a proportion of production and excretion as a proportion of intake. The results show that on HABIT N is more effectively conserved in mid-pregnancy through an increase in urea hydrolysis and salvage, and during late pregnancy through a reduction in urea formation. Lowering protein intake at any stage of pregnancy increased the hydrolysis and salvage of urea. The staging of these changes was later than that in pregnancy in Jamaica.

Urinary excretion of 5-L-oxoproline (pyroglutamic acid) is increased during recovery from severe childhood malnutrition and responds to supplemental glycine.

We hypothesized that a limitation in the endogenous formation of glycine might constrain catch-up growth during recovery from severe childhood malnutrition. The urinary excretion of 5-L-oxoproline is increased when the glycine available for glutathione synthesis is limited. Urinary excretion of 5-L-oxoproline was measured throughout recovery in 12 children (aged 16 +/- 6 mo) with severe malnutrition. Urinary 5-L-oxoproline was similar at admission and after recovery, but was increased significantly during rapid catch-up growth. There was a significant relationship between the rate of weight gain and 5-L-oxoproline excretion in urine. In nine children (aged 15 +/- 5 mo), the effect of oral supplementation with glycine, [1.7 mmol/(kg x d) for 48 h] during rapid catch-up growth on 5-L-oxoprolinuria and blood glutathione concentration was determined. In seven of the nine children weight gain was less than 17 g/(kg x d) and following oral glycine supplements 5-L-oxoproline excretion was reduced up to 64% and blood glutathione concentration increased up to 100%. In the two children who were gaining weight at a rate > 17 g/(kg x d), glycine supplementation was associated with a further increase in 5-L-oxoproline excretion and a decrease in blood glutathione. If 5-L-oxoproline is an index of the relative availability of glycine, then the data indicate that glycine may be limiting during rapid catch-up growth. This would have important implications for repletion of muscle and gain in height.

Dietary supplementation with L-methionine impairs the utilization of urea-nitrogen and increases 5-L-oxoprolinuria in normal women consuming a low protein diet.

Urea kinetics were measured in normal women after 5 d consuming a low protein diet [LP, 67 mg N/(kg.d), 0.42 g protein/(kg.d)]. To determine whether the availability of methionine limits the utilization of nonessential nitrogen from low protein diets, the study was repeated on four further occasions with the addition of dietary supplements of L-methionine, 9 mg N/(kg.d) (LP-M); urea, 52 mg N/(kg.d) (LP-U); urea and methionine (LP-UM); or urea, 26 mg N/(kg.d), and glycine, 26 mg N/(kg.d), (LP-UG). Urea kinetics were derived after prime and intermittent oral doses of [15N15N]urea from the measurements of enrichment by isotope ratio mass spectrometry in urea isolated from urine. Nitrogen balance was significantly improved when the women consumed LP-U and LP-UG, but not LP-M or LP-UM. The urinary excretion of 5-L-oxoproline was measured as a marker of glycine availability and was significantly lower when women consumed LP-U and LP-UG compared with either LP or LP-M and LP-UM. There was a significant correlation between urinary 5-L-oxoproline and urinary sulfate excretion (r = 0.68, P = 0.00003). The availability of methionine was not limiting for nitrogen metabolism when women consumed these diets, whereas the response to supplementation with urea alone or urea with glycine showed that the availability of nonessential nitrogen was limiting. Glycine is consumed in the detoxification of excess methionine, and supplementation with methionine appeared to place a competitive demand on the availability of glycine for other metabolic processes.

Infants in Trinidad excrete more 5-L-oxoproline (L-pyroglutamic acid) in urine than infants in England: an environmental not ethnic difference.

The demand for glycine to satisfy normal growth during early life is considerable and most has to be made endogenously. The extent to which adequate glycine is available can be assessed by measuring the urinary excretion of 5-L-oxoproline. The excretion of 5-L-oxoproline at 6 weeks of age for infants in Trinidad of African, Indian or mixed parentage (398 mumol/mmol creatinine) was significantly greater than for infants born in England of Caucasian parentage (194 mumol/mmol creatinine). There was no relationship between 5-L-oxoproline excretion and either sex or pattern of feeding. There were significant inverse relationships between 5-L-oxoproline/creatinine and birth weight, and head circumference either at birth or 6 weeks of age, suggesting that limited availability of glycine is associated with poorer growth before and after birth. For a group of infants born in England of Indian parentage, excretion of 5-L-oxoproline (155 mumol/mmol creatinine) was not different to infants of Caucasian parentage, but significantly less than infants born in Trinidad. The demonstration that 5-L-oxoproline/creatinine was similar in infants born in England, regardless of parentage, shows that the differences between England and Trinidad are related to environment and are unlikely to be accounted for by genetic differences or ethnicity.

Hyperinfection syndrome with Strongyloides stercoralis in malignant lymphoma.

Hyperinfection with Strongyloides stercoralis occurred in three patients with malignant lymphoma. The probable cause in each case was alteration of the immune responses either as a result of the malignant lymphoma or by the treatment given. Though thiabendazole (Mintezol) has produced reasonable results in the treatment of the hyperinfection syndrome, preliminary data suggest that the new broad-spectrum anthelmintic levamisole (Ketrax) is more effective. All patients who live or have lived in an area where strongyloidiasis is endemic should be investigated to detect the presence of the nematode before and during treatment with drugs with immunosuppressive properties. In view of the high mortality with S. stercoralis hyperinfection, vigorous therapy should be instituted before the use of immunosuppressive drugs.

An international survey of unrelated umbilical cord blood banking.

OBJECTIVES: To investigate operational and technical practices within the field of cord blood banking. MATERIALS AND METHODS: Cord blood banks world-wide were invited to participate in a survey of collection, processing and testing. The survey covered a 12-month period up to August 1998. RESULTS: Replies were received from 18 cord blood banks. Analysis of the survey responses demonstrated wide variations in many aspects of cord blood banking. CONCLUSION: There is a need for standardization to ensure adoption of best practice.