Temporal endurance of exercise-induced benefits on hippocampus-dependent memory and synaptic plasticity in female mice.

Exercise facilitates hippocampal neurogenesis and neuroplasticity that in turn, promotes cognitive function. Our previous studies have demonstrated that in male mice, voluntary exercise enables hippocampus-dependent learning in conditions that are normally subthreshold for long-term memory formation in sedentary animals. Such cognitive enhancement can be maintained long after exercise has ceased and can be re-engaged by a subsequent subthreshold exercise session, suggesting exercise-induced benefits are temporally dynamic. In females, the extent to which the benefits of exercise can be maintained and the mechanisms underlying this maintenance have yet to be defined. Here, we examined the exercise parameters required to initiate and maintain the benefits of exercise in female C57BL/6J mice. Using a subthreshold version of the hippocampus-dependent task called object-location memory (OLM) task, we show that 14d of voluntary exercise enables learning under subthreshold acquisition conditions in female mice. Following the initial exercise, a 7d sedentary delay results in diminished performance, which can be re-facilitated when animals receive 2d of reactivating exercise following the sedentary delay. Assessment of estrous cycle reveals enhanced wheel running activity during the estrus phase relative to the diestrus phase, whereas estrous phase on training or test had no effect on OLM performance. Utilizing the same exercise parameters, we demonstrate that 14d of exercise enhances long-term potentiation (LTP) in the CA1 region of the hippocampus, an effect that persists throughout the sedentary delay and following the reactivating exercise session. Previous studies have proposed exercise-induced BDNF upregulation as the mechanism underlying exercise-mediated benefits on synaptic plasticity and cognition. However, our assessment of hippocampal Bdnf mRNA expression following memory retrieval reveals no difference between exercise conditions and control, suggesting that persistent Bdnf upregulation may not be required for maintenance of exercise-induced benefits. Together, our data indicate that 14d of voluntary exercise can initiate long-lasting benefits on neuroplasticity and cognitive function in female mice, establishing the first evidence on the temporal endurance of exercise-induced benefits in females.

(99m)Tc-MIBI Whole Body Scan: A Potentially Useful Technique for Evaluating Metabolic Bone Disease.

Metabolic bone disease due to hyperparathyroidism is characterized by increased bone resorption and new bone formation. (99m)Tc- hexakis-2-methoxyisobutylisonitrile ((99m)Tc MIBI) accumulation is controlled by metabolic function and cell viability. To investigate, for the first time, the potential of whole body (99m)Tc MIBI scan for detecting, visually and with the aid of quantitative analysis, bony changes associated with hyperparathyroidism. Eighty-six patients with hyperparathyroidism, referred routinely for parathyroid localization, were included in this case-control prospective study. Each patient was injected with 20-25 mCi of (99m)Tc MIBI. Routine anterior cervico-thoracic images were obtained for parathyroid localization. Two extra whole body images were acquired and assessed visually and by drawing regions of interest over the mandible, sternum, femur, humeri, spine, and the soft tissue adjacent to the bone. The ratios of bone to soft tissue were calculated and compared to ratios drawn in a control group routinely referred for cardiac imaging and injected with (99m)Tc MIBI, after confirming the absence of any bone disease. The visual interpretation of the scans showed 48 patients to have increased bone uptake. Quantitative assessment showed significant difference between the mean ratios of the case and control groups. The Kruskal-Wallis test showed significant agreement between visual and quantitative ratios drawn from delayed right and left femora and left humerus images (P < 0.05). (99m)Tc MIBI whole body imaging is a potentially useful technique for assessing metabolic bone disease associated with hyperparathyroidism. Quantitative analysis helped in confirming the visual findings.

Re-evaluating the use of Voronoi Tessellations in the assessment of oxygen supply from capillaries in muscle.

The ability to characterise capillary supply plays a key role in developing effective therapeutic interventions for numerous pathological conditions, such as capillary loss in skeletal or cardiac muscle. However, quantifying capillary supply is fraught with difficulties. Averaged measures such as capillary density or mean inter-capillary distance cannot account for the local geometry of the underlying capillary distribution, and thus can only highlight a tissue wide, global hypoxia. Detailed tissue geometry, such as muscle fibre size, has been incorporated into indices of capillary supply by considering the distribution of Voronoi tessellations generated from capillary locations in a plane perpendicular to muscle fibre orientation, implicitly assuming that each Voronoi polygon represents the area of supply of its enclosed capillary. Using a modelling framework to assess the capillary supply capacity under maximal sustainable conditions in muscle, we theoretically demonstrate that Voronoi tessellations often provide an accurate representation of the regions supplied by each capillary. However, we highlight that this use of Voronoi tessellations is inappropriate and inaccurate in the presence of extensive capillary rarefaction and pathological variations in oxygen tension of different capillaries. In such cases, oxygen flux trapping regions are developed to provide a more general representation of the capillary supply regions, in particular incorporating the additional influences of heterogeneity that are absent in the consideration of Voronoi tessellations.

Presentation of Posterior Urethral Valves in Saudi Arabia in the 90's.

To evaluate the age and mode of presentation of patients with posterior urethral valves (PVU) in the antenatal and postnatal periods, we analyzed the files of 108 patients with the diagnosis of PUV in four referral hospitals in Riyadh, Saudi Arabia from 1989 to 1999. Of the study patients, 29 (27%) were antenatally discovered, 41 (38%) in the first year of life and 38 (35%) after the first year of life. The mode of presentation was by antenatal ultrasound in 29 (27%) patients, urinary tract infection in 33 (30.4%) patients, poor urinary stream in 35 (32.4%) patients, retention of urine in neonatal life in eight (7.4%) patients and symptoms of renal impairment in three (2.8%) patients. We conclude that the antenatal detection rate of PUV in our study patients is less than the international one (70%), despite the fact that most of the antenatal follow-ups were done in centers where ultrasound was available for routine antenatal work up. This calls for more vigilance by the radiologists and obstetricians to enhance the rate of detection of PUV.

Outcome of hypospadias repair using the tubularized, incised plate urethroplasty.

OBJECTIVE: We reviewed our results using the tubularized incised plate urethroplasty (Snodgrass procedure) for repair of penile hypospadias. MATERIALS AND METHODS: A total of 37 patients (aged 7-72 months, mean 17.5 months) underwent repair by three pediatric urologists at two institutions. The pre-op meatal position was distal in 28, mid-shaft in five, and penoscrotal in three patients. One patient, who did not have hypospadias, had a distal urethral fistula secondary to a previous circumcision. Twenty-six patients had ventral chordee and 12 required a dorsal tunica albuginea plication for correction. Urethroplasty was performed using 6-0 synthetic absorbable suture (PDS, Maxon, Dexon, or Monocryl). Urethroplasty coverage consisted of de-epithelialized dorsal preputial skin flap (32 patients), internal spermatic fascia flap (1 patient), tunica vaginalis flap (2 patients), or no coverage (2 patients). All patients were stented (8, 10 or 12 F silastic) for a mean duration of 9.8 days (range 4-12 days). Either a foam dressing (12 patients) or a Tegaderm sandwich dressing (25 patients) was used. RESULTS: Average length of hospital stay at one institution was 3.1 days (range 1-5 days). Mean follow-up was 8.8 months (range 1.5-20 months). The post-operative results were satisfactory with the meatus in a glanular position in 35 patients and a coronal position in two patients. All had a vertical orientation of the meatus. Complications included urethrocutaneous fistula in six patients, skin dehiscence in two patients, and meatal stenosis in two patients. One of the fistulas healed spontaneously. Urethral strictures have not been encountered thus far. CONCLUSIONS: The tubularized incised plate urethroplasty achieves satisfactory results with acceptable complications. It can be used for both distal and proximal hypospadias, and in the rare situation of fistula post-circumcision. Long term follow-up is needed to ensure that urethral strictures do not result from this technique.

Percutaneous nephrolithotomy in the pediatric population.

PURPOSE: Percutaneous nephrolithotomy is an established technique used in children with renal calculi. We review our experience with percutaneous nephrolithotomy for treating nephrolithiasis in childhood. MATERIALS AND METHODS: We retrospectively reviewed the records of children who underwent percutaneous nephrolithotomy procedures for renal calculi from 1985 to 1996. Antegrade percutaneous access was obtained in all patients and the tract was dilated to 24F. Grasper forceps, ultrasound and/or electrohydraulic lithotripsy was used to remove and disintegrate stones. In all patients a nephrostomy tube was placed intraoperatively, and a plain abdominal x-ray and nephrostogram were done postoperatively. The nephrostomy tube was removed after ensuring free drainage down the ureter and no untoward effects from clamping. Complete anatomical and metabolic evaluation was performed in all cases. Patients were followed 2 to 6 weeks, and 3 and 6 months postoperatively with a plain abdominal x-ray and excretory urography or renal ultrasound. RESULTS: In 5 boys and 3 girls (9 renal units) 4 to 11 years old (mean age 6.4) a total of 10 percutaneous nephrolithotomy procedures were performed. At presentation 6 children had flank and/or abdominal pain, 5 gross hematuria and 3 urinary tract infection. Three patients had associated metabolic abnormalities. One patient with a staghorn calculus had hydronephrosis and multiple infundibular stenoses. No underlying urological anatomical abnormalities were noted in the remaining cases. Four renal units that were obstructed at presentation required initial nephrostomy tube insertion. Average operative time was 131.8 minutes (range 58 to 240). An 87.5% stone-free rate was achieved using percutaneous nephrolithotomy monotherapy. Percutaneous nephrolithotomy was not successful for eradicating a staghorn stone in 1 patient. Hypothermia developed in 2 patients in whom operative time exceeded 150 minutes. No blood transfusions were required. CONCLUSIONS: Percutaneous nephrolithotomy is safe and effective in children, and should be considered a viable management option. However, staghorn calculi may require alternative management, particularly in the setting of underlying anatomical abnormalities. Children with renal calculi should undergo a complete anatomical and metabolic assessment with the institution of medical therapy, as appropriate.

Ureteroneocystostomy with and without the use of an intravesical catheter.

PURPOSE: Assessment of postoperative pain, analgesic requirements, bladder spasms, nosocomial urinary tract infections, length of hospital stay and outcome of "no catheter" versus catheterized intravesical ureteric reimplantation. MATERIALS AND METHODS: Over a 1 year period, 33 patients (24F, 9M) aged 3-14 years with surgical indications for ureteroneocystostomy were randomly assigned to a "no catheter" or "catheter" group. Intravesical ureteric reimplantation was performed in all patients. Post-operatively patients were given intravenous morphine for pain control and pain was assessed by a pain scale and by interviewing patients and parents regarding pain control. Urine cultures were performed on the day of surgery, and first and third postoperative days. Patients were followed post-operatively at 6 weeks with a renal ultrasound and at 3 months with a voiding or nuclear cystogram. Postoperative analgesic requirements, occurrence of bladder spasms, urinary tract infection rate, length of hospital stay and outcome as regards cure of vesicoureteric reflux were recorded. Student's paired t test was used for evaluation of statistical difference between groups. RESULTS: There was no difference in sex distribution, mean age or body weight, or nosocomial urinary tract infection rate between the 2 groups. Post-operative intravenous morphine requirement was significantly lower (p<0.05) in the "no catheter" group (mean +/- Standard Error of Mean (SEM) 0.51 +/- 0.4 mg/kg) versus the "catheter" group (0.89 +/- 0.5 mg/kg). Bladder spasms occurred in 80% of catheterized patients and 30% of non-catheterized patients. Length of hospital stay was significantly shorter (p<0.05) in the "no catheter" group (87.2+/- 19.4 hours) versus the "catheter" group (109.1 +/- 20.9 hours). All patients had stable kidneys by renal ultrasound at 6 weeks and cure of reflux by cystogram at 3 months, regardless of catheter status. CONCLUSION: Intravesical ureteroneocystostomy without a catheter is safe, well tolerated, and associated with significantly lower postoperative intravenous analgesic requirements, shorter hospital stay and fewer bladder spasms than the use of bladder catheters post-reimplantation. "No-catheter" reimplantation did not alter the expected outcome as regards cure of reflux.

Blood lipid concentrations and other cardiovascular risk factors among Saudis.

A study of 1005 family practice attenders at King Fahad National Guard Hospital was conducted during February 1993 to determine the prevalence of hyperlipidaemia and its association with participants' sociodemographic characteristics and clinical problems. The percentage of patients with total serum cholesterol concentration (TSCC) of 5.2-6.8 mmol/l was 39.3%, while those with TSCC exceeding 6.8 mmol/l was 9.5%. Hypertriglyceridaemia (TG > 2.5 mmol/l) was found in 5%. TSCC increased progressively with age up to the seventh decade. TSCC was higher among obese and diabetic patients than others. Obesity body mass index (BMI) > 29.9 kg/m2 was found in 32.8%, diabetes mellitus in 24.2%, hypertension in 11.1% and both diabetes and hypertension in 6.4%. There is an urgent need to equip primary health care teams with training and resources to help them give proper dietary advice, modify the local lifestyle and screen at least high-risk groups for hyperlipidaemia and other coronary risk factors.

Microbial pathogens from goat mastitis and phage-typing of Staphylococcus aureus isolates.

Examination of milk from goats yielded 41 strains from 40 clinically affected halves; 15 were Staphylococcus aureus, 6 Staph. epidermis, 1 Streptococcus agalactiae, 2 Strept. dysgalactiae, 5 Strept. uberis, 2 Corynebacterium pyogenes, 3 Escherichia coli, 3 Pasteurella spp. and 4 Mycoplasma spp. One half had dual infection of Staph. aureus and Strept. dysgalactiae. Twenty two of the 297 milk samples from apparently normal halves also harboured pathogens comprising of 9 Staph. aureus, 1 Strept. agalactiae, 2 E. coli, 2 Pasteurella spp., 2 Candida albicans and 6 Mycoplasma spp. Most of the bacterial isolates were sensitive to many broad spectrum antibiotics. Twenty of the 24 Staph. aureus isolates were phase typable by a set of 23 human Staphylococcal International Phages suggesting the utility of these phages for the typing of goat strains. The isolates were grouped into 15 phage-types, many of which have been reported from human infections in Iraq. This indicates the possibility of association of human strains of Staph. aureus in caprine mastitis. No definite correlation could be noted between antibiogram and phage types of Staph. aureus strains.

Receptor sites for mycoplasmal viruses on Acholeplasma laidlawii.

All three groups of mycoplasmal viruses tested, MVL1, MVL2, and MVL3, were inactivated by both membranes and lipoglycan from Acholeplasma laidlawii strain JA1. The interaction was specific for components of A. laidlawii since no inactivation occurred with either membrane or lipoglycan from Acholeplasma oculi. Adsorption of virus was proved by the demonstration of radiolabeled virus-lipoglycan or virus-membrane particles that were separable in density gradients from either component alone. Receptors essential for adsorption of MVL2 are part of the oligosaccharide chain of the lipoglycan since deacylation not only did not interfere but actually increased adsorption of virus per unit weight. More complex interactions involving membrane proteins were observed for MVL1 and MVL3.

Interaction of mycoplasma virus type 2 with cellular components of Acholeplasma laidlawii strain JA1.

Mycoplasma virus type 2 was shown to adsorb specifically to intact cells, membranes, and lipoglycan of Acholeplasma laidlawii strain JA1 but not to these components of Acholeplasma oculi. The oligosaccharide chain of the lipoglycan defined the specificity of the receptor site since deacylation not only did not reduce adsorption but increased it threefold. Actual adsorption of virus to lipoglycan was demonstrated by sucrose density gradient separation of the virus-lipoglycan complex. A strain of A. laidlawii, JA1r, resistant to infection with mycoplasma virus type 2, was incapable of adsorbing the virus and was devoid of lipoglycan.

An aldehydophosphoglycolipid from Acholeplasma granularum.

A novel phosphoglycolipid and a triglucosyl diacylglycerol were found among the lipids of Acholeplasma granularum. The tentative structure of the phosphoglycolipid was determined to be a phosphotriester, [beta-D-glucopyranosyl-(1 leads to 1)-X-glycerol-3-O-] [D-glyceraldehyde-3-O-] [1,2-diacyl-X-glycerol-3-O-kojibiosyl-6-O-]phosphate. The structure assigned to the triglucosyl lipid was beta-D-glucopyranosyl-(1 leads to 3)-alpha-D-glucopyranosyl-(1 leads to 2)-alpha-D-glucopyranosyl-(1 leads to 1)-diacylglycerol.

Lipid and lipopolysaccharide composition of Acholeplasma oculi.

The total lipid content of Acholeplasma oculi comprises 13.3% of the dry weight of the organism and is about equally distributed between the neutral lipids plus glycolipids and the phospholipids. The phospholipids were identified as phosphatidyl glycerol and diphosphatidyl glycerol. The glycolipid fraction contained O-alpha-D-glucopyranosyl-(1 leads to 1)-2,3-diacyl glycerol and O-alpha-D-glucopyranosyl-(1 leads to 2)-O-alpha-D-glucopyranosyl-(1 leads to 1)-2,3-diacyl glycerol. The neutral lipid contained pigmented carotenoids. Hot aqueous phenol extraction of lipid-extracted whole cells yielded a polymeric carbohydrate comprising 2.3% of the dry weight of the organism. The A. oculi lipopolysaccharide was found to contain only neutral sugars and no amino sugar, in contrast to other acholeplasmas. The neutral sugars consisted of fucose, galactose, and glucose in a ratio of 2:19:3.