Nasogastric intubation and elective abdominal surgery.

The use of nasogastric tubes after elective abdominal surgery remains standard practice for many surgeons. Such tubes, however, cause much discomfort and are associated with significant morbidity. This paper reviews the arguments for and against nasogastric intubation, and finds little evidence to support its continued routine use.     

Partial purification of acid phosphomonoesterase in axenically grown Entamoeba histolytica NIH-200.

Entamoeba histolytica possesses significant acid phosphatase activity as compared to alkaline phosphatase activity. The acid phosphatase activity in the amoebic cells eluted at higher saline concentration as three distinct peaks at 200, 300 and 400 mM sodium chloride.     

MRI assessment of the bony pelvis may help predict resectability of rectal cancer

OBJECTIVE: The outcome after surgical treatment of rectal cancer may be influenced by the technical difficulty of the operation, which is thought to be affected by pelvic size. The aim of this study was to examine the association between bony pelvic dimensions and CRM involvement. PATIENTS AND METHODS: All patients with primary rectal cancer between December 1999 and January 2002 were studied. Staging was performed by pelvic MRI. Nine pelvic dimensions were measured from the MR images on a workstation. Pathology reports were obtained for all patients and the mesorectal specimen was examined. Technical difficulty was assessed by circumferential resection margin (CRM) involvement. RESULTS: Of 126 patients with primary rectal cancer, 88 had staging MRI and rectal excision; there were significant differences between the sexes in all 9 pelvic dimensions (P < 0.05). In females, the interspinous diameter was significantly shorter in patients with CRM involvement compared with patients with a negative CRM. In female patients predicted to have a negative CRM, the anteroposterior diameter of the inlet, the anteroposterior diameter of the midplane and the transverse diameter of the midplane (interspinous distance) were significantly shorter in patients who actually had a positive CRM compared with those in whom the CRM was negative. In male patients, there was no correlation between pelvic dimensions and CRM status. CONCLUSIONS: In certain patients with rectal cancer, CRM positivity may be predicted from pre-operative MRI pelvic measurements. This may influence the choice of adjuvant therapy.     

Optimal field splitting for large intensity-modulated fields

The multileaf travel range limitations on some linear accelerators require the splitting of a large intensity-modulated field into two or more adjacent abutting intensity-modulated subfields. The abutting subfields are then delivered as separate treatment fields. This workaround not only increases the treatment delivery time but it also increases the total monitor units (MU) delivered to the patient for a given prescribed dose. It is imperative that the cumulative intensity map of the subfields is exactly the same as the intensity map of the large field generated by the dose optimization algorithm, while satisfying hardware constraints of the delivery system. In this work, we describe field splitting algorithms that split a large intensity-modulated field into two or more intensity-modulated subfields with and without feathering, with optimal MU efficiency while satisfying the hardware constraints. Compared to a field splitting technique (without feathering) used in a commercial planning system, our field splitting algorithm (without feathering) shows a decrease in total MU of up to 26% on clinical cases and up to 63% on synthetic cases.     

Optimal leaf sequencing with elimination of tongue-and-groove underdosage

The individual leaves of a multileaf collimator (MLC) have a tongue-and-groove or stepped-edge design to minimize leakage radiation between adjacent leaves. This design element has a drawback in that it creates areas of underdosages in intensity-modulated photon beams unless a leaf trajectory is specifically designed such that for any two adjacent leaf pairs, the direct exposure under the tongue-and-groove is equal to the lower of the direct exposures of the leaf pairs. In this work, we present a systematic study of the optimization of a leaf sequencing algorithm for segmental multileaf collimator beam delivery that completely eliminates areas of underdosages due to tongue-and-groove or stepped-edge design of the MLC. Simultaneous elimination of tongue-and-groove effect and leaf interdigitation is also studied. This is an extension of our previous work (Kamath et al 2003a Phys. Med. Biol. 48 307) in which we described a leaf sequencing algorithm that is optimal for monitor unit (MU) efficiency under most common leaf movement constraints that include minimum leaf separation. Compared to our previously published algorithm (without constraints), the new algorithms increase the number of sub-fields by approximately 21% and 25%, respectively, but are optimal in MU efficiency for unidirectional schedules.     

Pharmacokinetics of vindesine bolus and infusion

Summary The pharmacokinetics of vindesine were investigated during treatment of 15 patients with progressive malignancies refractory to conventional treatment. Patients were administered one of three IV dose schedules: 3.0 mg/m² bolus injection, 1.2 mg/m²/day infusion for 5 days, or 2.0 mg/m²/day infusion for 2 days. Concentrations of the drug in the serum and urine were determined by radioimmunoassay. Serum concentrations were highest (5×10^-7 M) in patients receiving a bolus injection, but fell to nondetectable levels by 48 h in four of five patients (terminal t_1/2 15.0±9.4 h). Compared with bolus injection, 1.2-to 1.4-fold greater areas under the blood concentration curve were observed during infusions of 2.0 mg/m² and 1.2 mg/m². Whereas steady-state concentrations (1×10^-8 M) were maintained throughout the infusion of 1.2 mg/m²/day progressively increasing serum levels were observed during the infusion of 2.0 mg/m²/day. Serum concentrations fell rapidly following discontinuation of the 2.0-mg/m² infusion, but were somewhat more sustained in the 1.2-mg/m² infusion group. The average urinary excretion was similar for each dose-schedule (8%–11% of the total dose). The pharmacokinetics of vindesine are influenced by variations in dose schedule.     

Acute pouchitis and deficiencies of fuel

PURPOSE: Acute pouchitis is a troublesome complication after restorative proctocolectomy. Deficiency of fuel, especially short chain fatty acids (SCFA), produced by anaerobic bacterial fermentation of saccharides, is implicated in ulcerative and diversion colitis. Our hypothesis was that SCFA deficiency occurs in acute pouchitis, and correction of the deficiency is associated with resolution of pouchitis. METHODS: Thirty-two patients were studied, 10 with histologically confirmed acute pouchitis and 22 with healthy pouches. Stool concentrations of SCFA (acetic, propionic, butyric, and valeric acids) were determined by gas-liquid chromatography. Quantitative bacteriologic studies of stool were carried out, and four-quadrant pouch biopsies were assessed by a pathologist who was unaware of the clinical state. Patients with pouchitis were treated for six weeks with metronidazole and given dietary advice to increase their intake of fermentable saccharides. RESULTS: Stool concentrations of SCFA were significantly less in pouchitis patients compared with patients with healthy pouches (340 mol/g (range, 124–492) vs.93 (range, 44–136) P<0.01). No differences in anaerobic or aerobic counts were seen. Resolution of pouchitis was associated with a significant increase in SCFA, but anaerobic counts fell. CONCLUSION: Deficiency of SCFA is implicated in acute pouchitis Read at the meeting of The American Society of Colon and Rectal Surgeons, Orlando, Florida, May 8 to 13, 1994.     

Morphine modulates cathepsin B and L activity in isolated glomeruli and mesangial cells

Altered matrix degradation may be playing a role in the development of initial mesangial expansion and subsequent glomerulosclerosis in persons with heroin abuse. We studied whether morphine, a metabolite of heroin, had any effect on lysosomal content of cathepsin B and L in mesangial cells. Morphine (10^–6 M) increased (P<0.01) mesangial cathepsin B and L activity (control, 22.1+2.2 vs. morphine, 31.4+1.4 mol NMec/g protein,N=5). Morphine (10^–6 M) also increased (P<0.01) glomerular cathepsin B and L activity (control, 0.1+0.01 vs. morphine, 2.2±0.2 pmol NMec/g protein,N=3). This effect of morphine occurred in a dose-dependent manner. These results suggest that morphine enhances cathepsin B and L activity in mesangial cells and isolated glomeruli. This effect of morphine may enhance capacity of mesangial cells to degrade increased amount of mesangial macromolecules.