Biomedical subjects

J C Langer

Publications and source records attributed to J C Langer.

134 records · Page 8Linked to original sources

PubMed1983

Effect of radiofrequency hyperthermia and chemotherapy on primary and secondary hepatic malignancies when used with metronidazole.

Hyperthermia is selectively toxic to neoplastic tissue. Since August 1981, 357 patients with incurable tumors in various body areas have been treated with chemotherapy and radiofrequency hyperthermia (RFHT) with adjuvant metronidazole at this center. Of this group, the cases of 102 patients with hepatic tumors are reported here. Patients received one to ten treatment courses, each course consisting of two to five daily RFHT sessions. Systemic temperature rose 0.6 +/- 0.3 degrees C during treatment, and tumor core temperature (measured by percutaneous transhepatic thermistor) reached 39.5 +/- 1.2 degrees C in 38 monitored patients. Results have been encouraging; in particular, among 15 patients with newly diagnosed colorectal metastases limited to the liver (and as yet untreated for their secondary disease), there has been objective partial tumor regression in 66.7%. Side effects have been few. Skin burns and subcutaneous fat necrosis were seen in 3.9% and 13.7% of patients, respectively. Tumor temperature is difficult to measure reliably and does not correlate with machine power or tumor response. A phase III trial is currently underway to determine the efficacy of RFHT and chemotherapy for patients with hepatic metastases from colorectal adenocarcinoma.

Adult↗

PubMedDate not supplied

Circumferential distribution of ganglion cells in the transition zone of children with Hirschsprung disease.

We prospectively studied the circumferential distribution of ganglion cells in the transition zone from a study population of 21 patients with Hirschsprung disease (HD) undergoing a pull-through procedure over a 26-month period. Twelve cases were satisfactory for examination, in that the transition zone was contained within a single surgical specimen and specimen distortion was minimal. Ganglion cells in the submucosa were counted in all 12 cases. In seven of the cases, the transition zone was proximal to the rectal sleeve and myenteric plexus ganglion cells were also counted. We found an uneven circumferential distribution of ganglion cells in both myenteric plexus and submucosa of the transition zone, resulting in a "leading edge" of ganglion cells extending into aganglionic distal bowel. The maximum length of this leading edge was 2.4 cm and 2.1 cm in the myenteric plexus and submucosa, respectively. Ganglion cells at the tip of the leading edge were present in clusters of up to six ganglion cells, in marked contrast to an absence of ganglion cells for most of the remainder of the circumference. Closely spaced myenteric plexus ganglia were seen at the tip of the leading edge in some cases. The leading edge was more frequently observed along the antimesenteric side, but this was not statistically significant. Our findings have relevance in the interpretation of intraoperative biopsies at the time of pull-through surgery and subsequent biopsies of neorectum in patients with surgically corrected HD.

Biopsy↗

PubMedDate not supplied

Feeding gastrostomy in neurologically impaired children: is an antireflux procedure necessary?

Some authors recommend a routine "protective" antireflux procedure (ARP) in neurologically impaired children undergoing feeding gastrostomy (FG). Over 4 years, we performed FG in 107 neurologically impaired children aged 1 month to 16 years. Ninety-eight had preoperative radiological assessment for gastroesophageal reflux (GER), which was documented in 44, of whom 33 had FG plus ARP and 11 had FG alone. Seven of the 11 subsequently developed symptomatic GER and 5 of them had a secondary ARP. Of the 54 children with no demonstrable GER preoperatively, 3 children underwent FG plus ARP. The remaining 51 had FG alone. There was one postoperative death. Of the 50 surviving patients, 22 developed symptomatic GER and 17 of these had a subsequent ARP. Mean follow-up of 20.0 months showed that the risk of developing GER after FG alone was not influenced by age, sex, indication for FG, underlying diagnosis, or method of gastrostomy. There was no significant difference in mortality and early morbidity between patients undergoing FG alone and those having FG with simultaneous or subsequent ARP. Only 44% of our patients in whom GER was not demonstrated initially developed symptomatic GER followed FG alone. This incidence does not justify a routine "protective" ARP.

Adolescent↗

PubMedDate not supplied

Intrafascicular injection of ammonium sulfate and bupivacaine in peripheral nerves of neonatal and juvenile rats.

BACKGROUND AND OBJECTIVES: Regional nerve blocks are often used for the treatment of postoperative pain in children. Ammonium sulfate is a non-narcotic anesthetic agent, which has been reported to provide pain relief lasting days to weeks, with few reported side effects in adult studies. Prior to considering clinical use in children, the neurotoxicity of ammonium sulfate in 4-day and 3-week old rats was assessed and compared with that of bupivacaine. METHODS: Each rat received a posterior tibial nerve intrafascicular injection (0.01 mL in 4-day-old and 0.02 mL in 3-week-old rats) using either 10% ammonium sulfate (n = 24 per age group), 0.5% bupivacaine (n = 18 per age group), 0.9% saline (n = 18 per age group), or 5% phenol (n = 18 per age group). A functional assessment by serial walking track analysis and a morphologic assessment by neurohistology were made. RESULTS: No abnormalities in serial walking track analysis and no structural nerve damage were detected after ammonium sulfate, bupivacaine, or saline injection. Bupivacaine caused mild focal changes in both age groups, which recovered by 8 weeks. CONCLUSIONS: Intrafascicular injection of ammonium sulfate was as safe as bupivacaine in this animal model. Further animal studies must be made before human trials are initiated.

Aging↗

PubMedDate not supplied

Adeno-associated virus gene transfer into renal cells: potential for in vivo gene delivery.

The human parvovirus adeno-associated virus (AAV), type 2, has a number of features that make it an attractive choice as a vector for gene delivery to the kidney. AAV vectors permit long-term gene expression in vivo by integration into the host genome, have potential for site-specific integration on chromosome 19, do not express viral genes or generate a cellular immune response, and demonstrate enhancement of gene expression by chemotherapeutic agents that are approved for use in vivo. These properties confer advantages to AAV over other viral and nonviral methods for gene transfer. Preliminary experiments in our laboratory suggest that AAV is able to transfer genes to both renal cells in culture and the kidney in vivo. Thus, AAV has the potential to be an important gene transfer vector for the kidney in vivo.

Dependovirus↗

PubMedDate not supplied

Diagnosis of intestinal ischemia in the rat using magnetic resonance imaging.

Noninvasive diagnosis of persistent ischemia after intestinal revascularization has remained an elusive goal. Because magnetic resonance imaging (MRI) can detect changes in tissue water, we studied its efficacy in differentiating ischemic from perfused intestine in an animal model. Six-week-old rats were subjected to (1) 30-min superior mesenteric artery (SMA) occlusion and reperfusion, (2) permanent SMA ligation, or (3) sham operation, and were then imaged for 90 min using a small-animal MRI scanner with T1 weighting (TR = 1000 msec, TE = 25 msec). In an additional group of rats, the experiment was repeated using a new contrast technique consisting of oral ferrite to decrease luminal signal and intravenous gadolinium to increase bowel wall signal. Mean abdominal intensity over the scanning period was calculated for each animal (n = 5 rats per experimental group). Definition of individual bowel loops was subjectively improved in animals scanned with intravenous and oral contrast. Mean abdominal intensity was significantly lower in ligated vs sham rats (43.90 +/- 8 vs 59.63 +/- 6 and 46.19 +/- 6 vs 54.26 +/- 6, with and without contrast, respectively). There was no significant difference in intensity between reperfused and sham animals. MRI differentiated persistently ischemic bowel from viable bowel in this model, both with and without the use of contrast. These data suggest that MRI may have a potential role in the noninvasive diagnosis of persistent intestinal ischemia.

Administration, Oral↗

PubMedDate not supplied

Diagnosis of persistent intestinal ischemia in the rabbit using proton magnetic resonance imaging.

Noninvasive diagnosis of persistent intestinal ischemia remains an elusive goal. Magnetic resonance imaging (MRI) recognizes changes in tissue water content, and several authors have demonstrated increased intensity within 6 hours of intestinal ischemia. To simulate the clinical situation more closely, we studied the efficacy of MRI in differentiating ischemic from viable segments of bowel 24 hours after injury in a rabbit model. A segment of distal ileum was rendered ischemic by vascular isolation and ligation. Controls underwent sham operation without vascular ligation. After 24 hours, multislice transverse scans were done using both T1 and T2 weighting. Image intensity was calculated from the isolated loop (absolute intensity), and paraspinal muscle intensity was used as an internal standard to calculate relative intensity (isolated bowel/paraspinal muscle). Animals were killed and bowel necrosis was confirmed histologically. Both absolute and relative intensity were significantly higher in animals undergoing persistent intestinal ischemia. This was true using both T1 and T2 weighting. In a further group of rabbits using the same model, intensity was calculated both before and after intravenous gadolinium. No significant difference was seen between sham and ischemic animals. Our data show that (1) MRI can differentiate ischemic from viable bowel 24 hours after ischemic injury, and (2) the use of intravenous contrast does not improve accuracy. We conclude that MRI may represent a useful noninvasive technique for the diagnosis of persistent intestinal ischemia and that clinical studies should be initiated.

Animals↗

PubMedDate not supplied

A preoperative protocol for the prevention of infection in children with tunnelled right atrial catheters.

The use of central venous lines has come to be widely accepted by children with cancer and their families. However, attendant infection is a cause of considerable morbidity. Coagulase-negative staphylococci, the predominant aerobic species on the skin, are now the commonest cause of catheter-related bacteremia. We introduced a protocol to reduce the colonization of the skin at the catheter insertion site. Antiseptic skin scrubs, with 4% chlorhexidine gluconate, were performed on the neck and anterior chest the night before and again on the morning of the surgical procedure. A single dose of cephalothin (or vancomycin for penicillin-allergic patients) was administered IV immediately before the operation. Compared to the 12 month period prior to initiation of this protocol, the rate of infections (occurring within 30 days of catheter placement) in the 3.5 year period of intervention dropped from 8 to 4.9 per 1,000 catheter days. The proportion of infections that were staphylococcal was reduced from 93 to 63% and the proportion of non-ports removed within 30 days of placement fell from 45 to 0%. Despite these changes, the major contribution to improved infection control appeared to be the use of an increased proportion of ports (a rise from <10 to almost 60%).

Administration, Topical↗