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Biomedical subjects

M E Zenilman

Publications and source records attributed to M E Zenilman.

At least 37 records · Page 2Linked to original sources
PubMed1996

General surgical care in the nursing home patient: results of a dedicated geriatric surgery consult service.

BACKGROUND: Although recent interest has centered on diseases that require operation in the elderly, few data are available about the effects of surgical intervention on the frail nursing home patient. STUDY DESIGN: A longitudinal study was conducted of the nature of illness requiring operation and intervention in residents of a geriatric center associated with a tertiary care medical center. A unique consult service for the patients was established and all referrals were prospectively followed up. RESULTS: The actuarial 18-month survival of patients referred was 35 percent. Although maintenance care (e.g., decubitus ulcer, stoma, and enteral tube care) made up a substantial number of referrals (32.5 percent), common surgical diseases of the abdomen, breast, and vascular system were routinely encountered (55 percent). In patients undergoing surgery, the 30-day mortality rate was 8.5 percent, and the complication rate 9.4 percent. Although patients undergoing major abdominal and vascular procedures had a higher complication rate (17.6) percent than those undergoing lesser procedures (6.3 percent, p = 0.05), there was no difference in the 30-day mortality (9.8 compared with 6.3 percent, respectively) or 18-month actuarial survival (33 compared with 32 percent, respectively) rates. The overall actuarial survival was adversely affected by the presence of coronary artery disease (relative risk [RR], 3.27) and dementia (Mini-Mental State Examination score less than 24; RR, 2.39) and age older than 70 years (RR, 2.03). The overall survival was unaffected by the actual need for operation, the magnitude of the procedure performed, gender, the number of comorbid conditions, and the preoperative code (resuscitative) status. CONCLUSIONS: Although nursing home patients referred for surgical intervention have poor survival rates, the use of surgical procedures does not adversely affect overall survival. This supports the idea that care for this patient population is not futile, and quality of life, patient dignity, and relief of suffering can provide a alternative to curative therapy.

Actuarial Analysis↗
PubMed1995

Competitive reverse-transcriptase polymerase chain reaction without an artificial internal standard.

Advances in our understanding of molecular and cellular physiology necessitate that mRNA levels for specific growth factors and other rare transcripts be measured quantitatively in small samples. Conventional methods such as Northern blot analysis and solution hybridization/ribonuclease protection are not sufficiently sensitive. We now report the theory, development, and validation of a rapid and highly sensitive assay, the RNA/DNA quantitative polymerase chain reaction (RD-PCR), which uses a competitive PCR approach to measure the number of copies of a specific mRNA per cell. Total nucleic acid (RNA and genomic DNA) is isolated from cells in culture. The mRNA of interest is first reverse-transcribed with an oligomer bearing a complementary sequence specific for the mRNA at its 3'-end, and a sequence complementary to an intron of the desired gene at the 5'-end. Competitive PCR is then performed in the presence of the cDNA product and endogenous genomic DNA, with an upstream primer complementary to the exon sequence of the gene of interest, and a downstream primer complementary to the intron sequence that was tagged to the cDNA. The cell's own genomic DNA is thereby used as the internal standard. To control for the efficiency of reverse transcription, a standard curve is used in each assay. The technique was validated by comparing the quantitation of insulin-like growth factor I (IGF-I) mRNA in two human cell lines by RD-PCR and by RNase protection analysis. Both methods gave similar numbers of copies of IGF-I mRNA per cell. For accurate analysis, RNase protection required at least 10(7) cells; RD-PCR required as little as 10(2) cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMed1995

Immediate laparoscopic cholecystectomy as definitive therapy for acute cholecystitis.

The objective of this study was to determine the safety and efficacy of immediate laparoscopic cholecystectomy in the management of acute calculous cholecystitis. A prospective data collection was performed on all patients admitted to one surgical service over a 2-year period. The patients were managed by a uniform protocol consisting of (1) preoperative ERCP when common duct stones were suspected; (2) operation within 24 h of diagnosis; and (3) selective operative cholangiography. Previous surgery was not a contraindication to inclusion. The setting was an urban teaching hospital. There were 52 patients, 34 females and 18 males. Nineteen had undergone previous abdominal surgery. Five patients had preoperative ERCP and five had intraoperative cholangiography. The patients underwent laparoscopic cholecystectomy 0.8 +/- 0.4 days postadmission. Four (7.7%) were converted to open cholecystectomy. Fifty-eight percent had spillage of bile and/or stones. Patients went home 2.3 +/- 1.6 days postoperatively. There were no deaths and two complications: a subhepatic biloma and a superficial wound infection. Follow-up of all patients has revealed no late complications. We conclude: (1) Immediate laparoscopic cholecystectomy is safe and effective for acute cholecystitis even when complicated by previous surgery, inflammatory adhesions, and gangrene. (2) Intraoperative spillage of bile and stones does not lead to an increase in early complications. (3) Cholangiography is needed only when clinically indicated. (4) Laparoscopic cholecystectomy should be the treatment of choice for patients admitted for acute cholecystitis.

Acute Disease↗
PubMed1995

Acute abdomen in the hemodialysis patient population.

BACKGROUND: The cause and frequency of the acute abdomen in patients undergoing hemodialysis are not well reported. Previous studies associate bowel infarction with hemodialysis, but dialysis generally is not implicated as a risk factor for mesenteric ischemia. METHODS: The records of 567 patients undergoing long-term hemodialysis during the period from July 1988 to June 1993 were retrospectively reviewed. RESULTS: Twelve patients (2.1% of the hemodialysis population) were admitted with acute abdominal pain or sepsis. They were demographically no different than their counterparts who did not have an acute abdomen. The final diagnoses were bowel infarction in 11 patients and acute pancreatitis in one. Principal areas of involvement were equally divided between large and small intestine and were due to nonocclusive mesenteric ischemia in all cases. Six patients had an occluded hemodialysis fistula on admission, suggesting hypotension and/or hypovolemia as a possible etiologic factor. Overall, mortality and major morbidity rates were 50% and 25%, respectively. CONCLUSIONS: An acute abdomen is a relatively uncommon problem in the hemodialysis population but is associated with a high mortality. Mesenteric infarction is the most common cause and should be the presumptive diagnosis until proven otherwise.

Abdomen, Acute↗
PubMed1994

Assignment of the human pancreatic regenerating (REG) gene to chromosome 2p12.

A cDNA termed reg (for regenerating gene) has been isolated and characterized from a rat pancreatic library. Expression of reg is markedly increased in regenerating islets and decreased when insulin gene expression is inhibited. These findings have led to the hypothesis that reg may be involved in the expansion of beta-cell mass during regeneration as well as in the maintenance of normal beta-cell function. The human reg gene has a high degree of similarity to the rat reg gene. To determine the chromosomal location of the human reg gene, we analyzed two panels of mouse- or hamster-human hybrid cell lines containing a single human chromosome or several different human chromosomes. DNA extracts from these cell lines were analyzed for the presence of the human reg gene by polymerase chain reaction. In addition, human metaphase chromosomes were used for fluorescence in situ hybridization to further confirm the chromosomal assignment and to determine the subchromosomal localization. With these approaches, we show that the human reg gene is located on the short arm of chromosome 2 near the centromere at band 2p12.

Animals↗
PubMed1994

Surgery in the nursing home patient.

Will a Geriatric Surgical Consult Service eventually develop into yet another surgical subspecialty? Precedent has been set in surgical fields such as pediatric and plastic surgery, and surely the expanding patient population will demand that some surgeons take care of the geriatric surgical patient full time. Those surgeons doing so will therefore become recognized experts and will be frequently consulted. The surgical problems faced by this unique patient population observed in our small series are most often straightforward. More complicated issues related to wound and intravenous line care, breast disease, and alimentary tract disease should be easily handled by an aggressive, conscientious, well-trained general surgeon.

Aged↗
PubMed1994

Telerobotic assisted laparoscopic surgery: initial laboratory and clinical experience.

OBJECTIVES: To assess the feasibility of telerobotic assisted surgery. METHODS: In a laboratory model, a cholecystectomy, splenectomy, and nephrectomy were performed by an inexperienced surgeon who was being mentored by an experienced surgeon stationed at a remote site. The remote surgeon controlled the laparoscopic camera by utilizing a telerobotic system. In patients, laparoscopic cholecystectomy, varix ligation, and bladder suspension were performed by an experienced team utilizing a robotic system controlled by an experienced surgeon from a remote site. RESULTS: In both the laboratory and clinical setting, all procedures were successfully completed without complications. CONCLUSIONS: Current technology is available to successfully allow for telerobotic assisted surgery.

Animals↗
PubMed1993

Groin lymphorrhea complicating revascularization involving the femoral vessels.

Seven (4%) of 193 patients developed lymphoceles in 8 (2%) of 316 groin wounds after 211 arterial reconstructive procedures. Included were 91 aortic, 15 extra-anatomic, and 105 infrainguinal revascularizations. Lymphoceles developed in otherwise uncomplicated wounds in 6 (8%) of 73 patients with oblique incisions and bilaterally in 1 (1%) of 120 patients with vertical incisions (p = 0.01). This difference may be related to the surgical technique, with increased lymphatic damage and inadequate wound closure in the oblique approach. No increased incidence of lymphorrhea was noted in those patients undergoing aortic reconstruction regardless of the type of incision used (p = 0.15), or when compared with patients who had undergone extra-anatomic or infrainguinal bypass (p = 0.14). Each lymphocele was persistent, and external fistulas spontaneously occurred in three. Diagnosis was based upon clinical awareness and the appearance of the groin mass. Conservative management was uniformly unsuccessful, and operative ablation of the lymph fistula and lymphocele proved to be definitive therapy.

Adult↗
PubMed1993

Origin and control of gastrointestinal motility.

As a result of improved understanding of the origin and control of motility at both the whole organ and the cellular level, a scientific approach to the diagnosis and treatment (both medical and surgical) of motility disorders has evolved. Examples are present for all levels of the gastrointestinal tract. Manometric, myoelectric, and pharmacologic studies have elucidated the role of the lower esophageal sphincter and stomach in the pathogenesis of gastroesophageal reflux and determined the mechanism of successful medical and surgical treatment. Better evaluation of colorectal motility using colonic transit studies, pelvic floor radiography, and rectoanal manometrics has led to a better identification of both the etiology of severe constipation and patients who will have a successful surgical outcome. Studies of normal and abnormal gallbladder motility and responsiveness to hormonal stimulation have shed light on the cellular abnormalities in gallbladder myocytes that predispose to gallstone formation. Finally, since we have learned that certain surgical procedures affect motility in an adverse manner, a better basic understanding of gastrointestinal physiology has led to a better clinical understanding of the mechanism by which the changes occur and to the development of more directed physiologic operations. The classic example is seen in ulcer surgery, where the introduction of highly selective vagotomy instead of truncal vagotomy preserved antral innervation and decreased the incidence of postvagotomy complications. All these concepts and more are addressed in more detail in subsequent articles in this issue.

Animals↗
PubMed1992

Preservation and propagation of cyclic myoelectric activity after feeding in rat small intestine.

The cyclic nature and distal propagation of the fasting migrating motor complex (MMC) of the small intestine have been well described. The fate of the MMC after feeding, however, has not been elucidated. We used time series analysis with fast Fourier transforms (FFT) to study myoelectric cycling before and after feeding. Ten rats were chronically prepared with bipolar electrodes secured to the duodenum and proximal jejunum. Spikeburst frequency was recorded before and after feeding simple nutrients. During fasting, cyclic activity occurred at the MMC frequency. Although after feeding this periodicity appeared disrupted, FFT analysis showed persistent cycling at the fasted (MMC) rate. Digital filtering of data at the MMC frequency isolated cycling from background noise during both fasted and fed states and showed a depression in the amplitude of the waveform after feeding. Root-mean-square analysis of the waveform confirmed statistically significant depression of amplitude by 47-57%. The waveform propagated from the duodenum to the jejunum during both the fasted and fed state at an unchanged rate. We conclude that factors controlling myoelectric cycling during the fasted state persist after feeding, allowing continued net abroad propulsion of food.

Administration, Oral↗
PubMed1990

Substance P stimulates the opossum sphincter of Oddi in vitro.

We have previously shown that substance P (SP) regulates sphincter of Oddi (SO) motility in vivo. However, its mechanism of action remains unclear. Our aim was to develop an in vitro model to measure spikeburst (SB) an contractile frequency (CMC) of the SO and to characterize further SP effects. In 16 opossums, SO rings were excised, mounted within a Kreb's tissue bath with bipolar electrodes and force transducers, allowed to equilibrate, and exposed to increasing SP concentrations with washout between each test solution. Spikeburst and CMC frequencies were recorded on a polygraph, quantitated, expressed as differences before and during SP, and statistically analyzed with Student's test. Although SP induced a significant concentration-dependent increase in phasic SB frequency and CMC, the amplitude of concentrations was not affected by SP. A close correlation was found between basal and SP-stimulated SB and CMC, suggesting myoelectric and mechanical coupling. Previous exposure of SO to SP antagonist [D-Arg1, D-Pro2, D-Trp7,9, Leu11]-SP significantly decreased the response to SP. Tetrodotoxin (TTX), did not affect the delta CMC response to SP. In conclusion an in vitro preparation was developed to study the effect of SP on the SO. Substance P increased SB and CMC of the SO in a concentration-dependent fashion, thus acting as a stimulatory peptide. Perfusion of SO rings with SP antagonist had no effect on basal CMC but significantly inhibited the action of SP in a competitive manner. The effect of SP was not altered by TTX. These data suggest that the action of SP on the SO is primarily myogenic.

Action Potentials↗
PubMed1990

Time-series analysis of myoelectric cycling of sphincter of Oddi: evidence of cycling during fed state.

The sphincter of Oddi (SO) in the fasted opossum exhibits spontaneous cyclic spikeburst activity that is temporally related to the interdigestive migrating myoelectric complex (MMC) of the small intestine. After feeding, the cyclic activity is apparently disrupted. Our aim was to use time-series analysis to mathematically describe the periodic behavior of the fasted state and to determine whether this periodicity is present after feeding. Five opossums were chronically prepared with bipolar electrodes secured to the SO. With the animals fasted and conscious, myoelectric activity was recorded for at least two MMC cycles after which they were fed 170 kcal of cream. Spikeburst frequency data were analyzed by fast Fourier transform (FFT) and by digital band-pass filtering. Results from FFT analysis showed an intense low-frequency peak during the fasted state which persisted but was markedly depressed during the fed state. Analysis of the data after filtering also showed persistent sinusoidal activity at the MMC frequency after feeding, although the waveform was significantly depressed by both peak-to-peak amplitude and root mean square amplitude analysis. Recovery to normal fasting cyclic behavior with recovery of both FFT and filtered data was observed. We conclude that in the opossum the cyclic nature of the SO myoelectric activity observed during the fasted state persists after feeding, but is inhibited and masked by an increase in overall spikeburst activity.

Ampulla of Vater↗
PubMed1989

Successful surgical treatment of idiopathic colonic dysmotility. The role of preoperative evaluation of coloanal motor function.

Identification of patients with severe idiopathic colonic dysmotility who would benefit from surgery can be difficult. Colonic transit studies and anorectal manometry were applied to 12 women with severe constipation before subtotal colectomy. Delayed transit was noted in all patients with most exhibiting left-sided colonic arrest. Mean anal resting pressure and rectal capacity were similar to that in healthy controls. Pathologic examination results revealed decreased argyrophilic neurons in the colonic myenteric plexus. At 24 months postoperatively, all patients were satisfied with their results and mean (+/- SEM) weekly bowel movement frequency was 17 +/- 3 (compared with 0.8 +/- 0.2 preoperatively). Preoperative coloanal function studies therefore aid in the selection of patients who will be successfully treated by surgery. Subtotal colectomy with ileorectal anastomosis is the preferred operation because dysmotility can originate from either side of the colon.

Adult↗
PubMed1989

Characterization of substance P effects on sphincter of Oddi myoelectric activity.

We examined the effects of substance P (SP) on the myoelectric activity of the opossum sphincter of Oddi (SO). Myoelectric data from the SO in five adult opossums were recorded using thin stainless steel electrodes and computer-assisted analog-to-digital conversion. In fully awake and conscious animals, baseline spikeburst activity during phase I of the MMC occurred at a frequency of 28.6 +/- 3.1 spikebursts (SB) per 20-min period. Intravenous infusion of graded doses of substance P (from 0.5 to 8.0 micrograms/kg) stimulated SO myoelectric activity in a dose-related manner (from 80 +/- 8 to 235 +/- 11 SB/20 min, respectively, P less than 0.05 when compared to baseline). The effect of substance P on SO myoelectric activity was antagonized by administration of the H2-blocker, cimetidine (92.0 +/- 6.1 vs 48.2 +/- 7.0, n = 5, P less than 0.05). Administration of the antimuscarinic drug atropine only slightly affected the SO spikeburst frequency when infused prior to SP (73.0 +/- 10.4 vs 70.8 +/- 8.2, P greater than 0.05). We conclude that SP stimulated the SO spikeburst frequency in a dose-dependent fashion. Cimetidine markedly inhibited the response of the SO to SP but atropine did not. The excitatory effect of substance P on the opossum SO is mediated at least in part by a histaminergic, noncholinergic pathway.

Ampulla of Vater↗