Productivity and nitrogen use of three different wheat-based rotations in North West Syria

Productivity of 3 different 2-year crop rotations, namely continuous wheat, wheat-chickpea, and wheat-fallow, was measured over 4 consecutive seasons beginning in 1991-92 at the ICARDA station, Tel Hadya, Syria. Nitrogen (N) fertiliser (30 kg N/ha at sowing) was broadcast every other year in the continuous wheat only. 15N-labelled fertiliser was used to quantify the amount of nitrogen supplied to the crops through current and past applications of fertiliser and by N2 fixation. The remaining N in the crop was assumed to come from the soil. In any single season, wheat yields were unaffected by rotation or N level. However, 2-year biomass production was significantly greater (32%, on average) in the continuously cropped plots than in the wheat-fallow rotation. On average, <10% of the N in the wheat crop came from fertiliser in the season of application, and <1·2 kg N/ha of the residual fertiliser was recovered by a subsequent wheat crop. Chickpea fixed 16-48 kg N/ha, depending on the season, but a negative soil N budget was still likely because the amount of N removed in the grain was usually greater than the amount of atmospheric N2 fixed. Uptake of soil N was similar in the cereal phase of all 3 rotations (38 kg N/ha, on average), but over the whole rotation at least 33% more soil N was removed from continuously cropped plots than from the wheat-fallow rotation, suggesting that the latter is a more sustainable system. A laboratory study showed that although wheat and chickpea residues enhanced the gross rate of N mineralisation by c. 50%, net rates of N mineralisation were usually negative. Given the high C/N ratio of the residue, immobilisation, rather than loss processes, is the likely cause of the decline in the mineral N content of the soil. Consequently, decomposition of crop residues in the field may in the short term reduce rather than increase the availability of N for crop growth.

Design, testing, and results of an outcomes-managed approach to patients requiring prolonged mechanical ventilation

BACKGROUND

Outcomes management that uses critical pathways may decrease costs while improving outcomes for patients who require prolonged mechanical ventilation.

OBJECTIVE

To study the efficacy of an outcomes-managed approach to weaning patients from prolonged (more than 3 days) mechanical ventilation.

METHODS

A method of multidisciplinary care delivery was designed that included an outcomes manager, a care pathway for patients receiving mechanical ventilation, and weaning protocols. Data collection consisted of three parts: a retrospective review of 124 patients who required prolonged ventilation during a 1-year period before implementation of the care model, a 6-month prospective study in which 91 patients were alternately assigned by month to an outcomes-managed approach or a non-outcomes-managed approach, and a 6-month prospective study of 90 patients in which an outcomes-managed approach without alternate-month assignment was used.

RESULTS

Outcomes management had no significant effect on total duration of mechanical ventilation or length of stay in the hospital, days of mechanical ventilation without tracheostomy, days of mechanical ventilation with tracheostomy, or outcome (weaned, withdrawal from mechanical ventilation, death, or transfer without weaning). However, duration of mechanical ventilation was 1.3 days shorter, length of stay in the hospital was 2.1 days shorter, and the cost per case was $ 3341 less for patients in the outcomes-managed group than for patients in the non-outcomes-managed group.

CONCLUSION

Outcomes-managed care did not have a significant effect on duration of ventilation, length of stay in the hospital, or outcome in patients receiving long-term mechanical ventilation.

Reliability and validity of the Gastrointestinal Symptom Rating Scale in patients with gastroesophageal reflux disease

The objective of this study was to evaluate the reliability and validity of the gastrointestinal Symptom Rating Scale (GSRS) in US patients with gastroesophageal reflux disease (GERD). Five hundred and sixteen adults with predominant heartburn symptoms of GERD were recruited from gastroenterologist and family physician practices and treated with 6 weeks of 150 mg ranitidine twice daily to identify poorly responsive symptomatic GERD. The GSRS, the Medical Outcomes Study Short Form-36 (SF-36) Health Survey and the Psychological General Well-being (PGWB) scale were administered at baseline and after 6 weeks of treatment. Reported ratings of GERD-related symptoms from physician and patient diaries were measured. The GSRS contains five scales: reflux syndrome, abdominal pain, constipation syndrome, diarrhoea syndrome and indigestion syndrome. The internal consistency reliabilities for the GSRS scales ranged from 0.61 to 0.83 and the intraclass correlation coefficients ranged from 0.42 to 0.60. The GSRS scale scores were correlated with the SF-36 and PGWB scales and with the number and severity of heartburn symptoms. Patients with two or three clinician-rated GERD-related symptoms reported worse GSRS scale scores compared with patients with fewer symptoms (p < 0.0001). Statistically significant differences in the mean GSRS scale scores were observed between treatment responders and non-responders (p < 0.0001) and patients showing a response to treatment had larger mean changes in their GSRS scales than patients not showing a response to treatment (p < 0.0001). The standardized response means ranged from 0.42 to 1.43 for the GSRS scale scores. It was concluded that the GSRS is a brief, fairly comprehensive assessment of common gastrointestinal symptoms. The GSRS has good reliability and construct validity and the GSRS scales discriminate by GERD symptom severity and are responsive to treatment. The GSRS is a useful patient-rated symptom scale for evaluating the outcomes of treatment for GERD.

Evolution of the lateral canthoplasty: techniques and indications

Lateral canthoplasty is a useful method to restore eyelid function and to protect the ocular surfaces. The success of the procedure depends on the proper analysis of periorbital anatomy as it relates to the specific indication for lateral canthoplasty. We report the experience with 1565 lateral canthoplasties with emphasis on the evaluation of newer techniques that better address anatomic and functional requirements. Between 1981 and 1994, 1565 lateral canthoplasties were performed in 684 patients. Of these, 1369 "reconstructive" lateral canthoplasties were performed in 586 patients and 196 "cosmetic" lateral canthoplasties were performed in 98 patients. All operations were performed by a single surgeon (Jelks), and follow-up ranged from 1 to 14 years. The evolution of the operative technique for lateral canthoplasty has been toward an operation that corresponds with the anatomy of the individual. Indications for the procedure include lateral canthal dystopia, horizontal lid laxity, ectropion, entropion, lid margin eversion, lid retraction with or without soft-tissue deficiency, and aesthetic improvement. The types of procedures performed will be reviewed in detail. The evaluation of the newer forms of lateral canthoplasty as unique reconstructive tools and as adjuncts to aesthetic surgery will be discussed.

Norepinephrine release in the human forearm: effects of epinephrine

It has been postulated that delayed facilitation of norepinephrine release by epinephrine is causally related to the development of hypertension. It has been proposed that a brief increase in epinephrine concentrations results in the uptake of epinephrine into the sympathetic nerve terminal. Subsequent rerelease of epinephrine stimulates presynaptic beta-adrenergic receptors, resulting in a prolonged increase in plasma norepinephrine (NE) concentrations, with amplified sympathetic responses and vasoconstriction. To determine whether such epinephrine-induced, delayed facilitation of NE release occurs in a vascular bed draining resistance vessels and, if it occurs, whether that facilitation differs in hypertension, we used a radioisotope dilution method to measure unstimulated and isoproterenol-stimulated forearm NE spillover before, during, and after a 50 ng/min infusion of epinephrine for 30 minutes directly into the brachial artery. No delayed facilitatory effects of epinephrine on forearm NE spillover were observed in either 6 normotensive (NT) or 8 borderline hypertensive (BHT) subjects (NT unstimulated forearm NE spillover preepinephrine 1.79+/-0.41 ng/min versus postepinephrine 2.36+/-0.65 ng/min, P=.38; BHT preepinephrine 2.24+/-0.70 ng/min versus postepinephrine 1.93+/-0.46 ng/min, P=.51; NT isoproterenol-stimulated forearm NE spillover preepinephrine 4.61+/-1.01 ng/min versus postepinephrine 4.4+/-0.98 ng/min, P=.9; BHT preepinephrine 4.04+/-1.36 ng/min versus postepinephrine 4.69+/-1.49 ng/min P=.5). We conclude that the short-term local infusion of epinephrine does not have a delayed facilitatory effect on forearm NE spillover in NT or BHT subjects. Therefore, the prolonged increase in NE concentrations after epinephrine infusion previously shown systemically, and not seen locally in the forearm, suggests that the delayed facilitatory response to epinephrine may occur in other organs.

The relationship between cytochrome P4502E1 activity and plasma fluoride levels after sevoflurane anesthesia in humans

We determined whether the perianesthetic plasma fluoride levels after sevoflurane anesthesia in humans were correlated with the metabolic ratio (MR) of 6-hydroxychlorzoxazone to chlorzoxazone, an in vivo probe for cytochrome P4502E1 (CYP2E1) activity. Thirty ASA physical status I or II patients scheduled for extraabdominal surgery were randomized to a chlorzoxazone (n = 20) or a control group (n = 10). Patients in the chlorzoxazone group received 500 mg chlorzoxazone orally on the morning of the day of surgery. Chlorzoxazone and its 6-hydroxymetabolite concentrations were measured in plasma 2 h after drug administration. Anesthesia was induced with propofol, fentanyl, and atracurium intravenously and maintained with sevoflurane (inspired concentration 1-3 vol%). Plasma fluoride concentrations were determined before the induction of anesthesia, at the cessation of sevoflurane, and 2, 4, 6, 10, and 24 h thereafter. The area under the plasma fluoride concentration-time curve (AUC) was calculated up to 24 h after sevoflurane cessation. MR correlated significantly with the plasma fluoride AUC (r2 = 0.28, P < 0.025), the elimination constant calculated for the postanesthetic 10- to 24-h period (r2 = 0.30, P < 0.025), and the plasma fluoride levels 24 h after the cessation of sevoflurane (r2 = 0.48, P < 0.05). A comparison between groups indicated that the administration of chlorzoxazone itself did not alter the postanesthetic fluoride kinetics. Thus, the interindividual variability in perianesthetic plasma fluoride levels after sevoflurane anesthesia is reflected by differences in the MR of chlorzoxazone and hence is related to the interindividual variability in CYP2E1 activity. We conclude that although the predictive value is limited, this study provides a reasonable basis for examining renal function after sevoflurane anesthesia in a subgroup of patients with a high preoperative metabolic ratio of chlorzoxazone.

IMPLICATIONS

CYP2E1 metabolizes sevoflurane as measured by the metabolic ratio of chlorzoxazone. Patients with a high ratio may be used to justify examining renal function in patients receiving sevoflurane.

Report on primate supply for biomedical scientific work in the UK. EUPREN UK Working Party

A Working Party of the UK group of European Primate Resources Network (EUPREN) considered primate supply for scientific work in the UK. Through a questionnaire, which achieved a very good response, it obtained details of primate use, sources and breeding in the UK and it put forward options to ensure that animal welfare is the best possible whilst ensuring continued supply. The questionnaire showed that contract research laboratories and pharmaceutical companies use about 80% of the 4233 primates used annually at the moment, with the rest accounted for by academic establishments and public sector laboratories. Fifty-four per cent are cynomolgus macaques (Macaca fascicularis), of which nearly 90% are captive-bred outside the European Union (EU), the remainder being bred in the UK. Nearly 90% of cynomolgus macaques are used by only five institutions. Thirty-seven per cent of primates used are marmosets (Callithrix jacchus jacchus), all of which are bred in the UK. Most of the rest are rhesus macaques (Macaca mulatta), about half of which are captive-bred outside the EU, the other half being bred in the UK. Overall primate use has increased from about 3000 per year in 1990 and users predict that requirements for all species except baboons (Papio sp.) will be maintained or increase. Marmoset breeding in the UK is already closely matched to use, and it could be increased reasonably easily if necessary. Some of the existing breeding centres of macaques in the UK would be prepared to consider expanding to supply others, although investment and imported breeding stock would be needed and it is likely that a large investment would be needed to breed a significant fraction of the macaque use in the UK. A further problem is that the users of only about 10% of the cynomolgus macaques said that they could replace this species by rhesus macaques, which are easier to breed in the UK. The questionnaire showed that much of the use of macaques would be transferred to other countries equally remote from the natural source countries of the animals, if constraints on primate use became more severe in the UK. Users felt that it is unlikely that much of the work could be transferred to the natural source countries themselves. A review of the literature revealed a paucity of information on the effects of transport on primate welfare. The importance of obtaining this information before making decisions about alternative means of supply is stressed. Current schemes for the accreditation of primate breeders were reviewed. A list of options is presented for discussion. Users vary so much in their requirements that it is unlikely that one means of supply will be applicable to all. Animal welfare will benefit and supply will be more certain if cooperation between those concerned (preferably through the UK group of EUPREN) is maintained.

Plasma morphine and glucuronide (M3G and M6G) concentrations in hospice inpatients

Plasma morphine, morphine-3-glucuronide (M3G), and morphine-6-glucuronide (M6G) concentrations were quantified by high performance liquid chromatography (HPLC) in 36 hospice inpatients receiving morphine orally or subcutaneously. The data were analyzed in relation to dose, serum creatinine, serum gamma glutamyl transferase, and presence or absence of opioid-induced adverse effects. There were significant associations (P < 0.05) between plasma morphine, M3G (subcutaneous route only), and M6G concentrations and dose for both routes of administration. The mean dose-corrected plasma morphine concentration for the subcutaneous group was three times that of the oral group, confirming present oral to subcutaneous dose conversion practices. Nineteen patients experienced symptoms attributed to morphine: nausea and vomiting in ten and acute delirium in nine. Serum creatinine was elevated in patients with adverse effects (P = 0.031), as were the dose-corrected plasma M3G (P = 0.029) and M6G (P = 0.043) concentrations. All seven patients with serum creatinine concentrations above the normal range had symptoms attributed to opioid-induced adverse effects. Plasma M3G, M6G, and dose-corrected plasma M3G and M6G concentrations were significantly (P < 0.001) higher in these patients than in those with normal serum creatinine concentrations. The data indicate that accumulation of M3G and M6G may be a causal or aggravating factor in the nausea and vomiting and cognitive function profile of palliative and terminal care patients with significant renal function impairment.

Sympathoinhibitory response to clonidine is blunted in patients with heart failure

To determine whether alpha2-adrenergic-mediated sympathoinhibition was altered in chronic heart failure, sympathoinhibitory sensitivity was assessed using the alpha2-adrenergic agonist clonidine in 7 patients with heart failure and in 10 healthy control subjects. Basal norepinephrine spillover was significantly higher in patients with heart failure (1.3+/-0.3 microg/min) than in control subjects (0.7+/-0.1 microg/min, P=.05). Compared with control subjects, the decrement in norepinephrine spillover to cumulative doses of clonidine (1, 2, and 3 microg/kg administered intravenously) was significantly less in patients with heart failure (P<.05). Blood pressure also tended to decrease less in patients with heart failure (P=.06). The doses of clonidine required to produce a 10% decrease in blood pressure and a 25% decrease in norepinephrine spillover were significantly higher in heart failure (P<.01 and P=.05, respectively). Thus, although clonidine lowers norepinephrine spillover significantly in patients with heart failure, such patients are less sensitive to clonidine than healthy control subjects. This difference in sensitivity suggests that doses of clonidine provide effective sympathoinhibition will need to be selected for studies that will evaluate the potential therapeutic effect of clonidine in heart failure.

Cross-linking hybridization assay for direct detection of factor V Leiden mutation

A nucleic acid photocross-linking technology was used in the development of a direct assay for factor V Leiden, a point mutation in the factor V gene (G1691A) that is the most common inherited risk factor for thrombosis. This cross-linking hybridization assay included two allele-specific capture probes and six signal-generating reporter probes; all were modified with a photoactivated cross-linking compound. By using two different capture probes complementary to a 16-base sequence at the factor V Leiden mutation site, but differing in the nucleotide opposite the mutation site (C vs T), wild-type and factor V Leiden alleles were differentiated in purified DNA specimens. The assay was also successfully applied to genomic DNA in leukocytes isolated from whole blood; the factor V status of 122 patients as determined by this method was in complete concordance with a standard PCR-based assay and clearly discriminated between healthy individuals and factor V Leiden heterozygotes.

Stress in mental health nursing: findings from the Mental Health Care survey

Organisational and administrative concerns topped the list of stressors reported by a national sample of hospital and community mental health nurses. Seven of the ten top stressors were listed by both groups. Community nurses also listed inadequate service provision and lack of time to plan treatment. Hospital nurses were most stressed by inadequacy of staffing cover in potentially dangerous situations and low morale at work. Jerome Carson et al believe the findings indicate an urgent need for change at senior NHS management and administration level.

Blunted blood pressure response to central sympathoinhibition in normotensive blacks: increased importance of nonsympathetic factors in blood pressure maintenance in blacks

Enhanced sympathetic reactivity may predispose blacks to the development of hypertension and may occur because of increased sympathetic stimulation and/or attenuated sympathoinhibition. A potential site for such attenuated sympathetic inhibition may be at the level of central alpha2-adrenergic receptors, which play an important role in the feedback inhibition of norepinephrine release. We used cumulative doses (1, 2, and 3 microg/kg I.V.) of the centrally acting alpha2-adrenergic agonist clonidine to measure the sensitivity of alpha2-adrenoceptor-mediated sympathoinhibition and the resultant hypotensive response in 8 normotensive blacks and 10 normotensive whites. Sympathetic activity was determined by radioisotope dilution methodology. Basal norepinephrine spillover was similar in blacks (0.80+/-0.14 microg/min) and whites (0.73+/-0.19 microg/min, P=NS) and after clonidine decreased significantly in both blacks (0.21+/-0.07 microg/min, P<.0001) and whites (0.24+/-0.06 microg/min, P<.0001), with no difference between the groups (P=NS). Despite this similar degree of sympathoinhibition, the hypotensive response to clonidine was markedly blunted in blacks, such that mean arterial pressure decreased by only 10% in blacks but by 21% in whites (P<.0001). The smaller blood pressure decrement after clonidine in normotensive blacks, in the face of an equal degree of sympathoinhibition, suggests that even when sympathetic tone is decreased to the same level in blacks and whites, normotensive blacks have less reduction in blood pressure than whites, implying that nonadrenergic mechanisms contribute more to blood pressure maintenance in blacks than whites. Whether a similar interethnic difference in response to sympathoinhibition occurs in hypertensive patients is as yet unknown.

Managing patient records and documenting service delivery: the results of a 'best practice' remote area nursing program

This paper describes a 'best practice' demonstration program for monitoring nursing services in remote locations. A four-phase project involving paper- and computer-based patient information systems was implemented at nursing clinics on islands off the coast of Queensland. Patient demographics, diagnoses and details of health service provision were recorded. Results showed a marked improvement in the detail of patient records over the program period. Monitoring of services also provided useful planning and policy information for company management, while a systematic approach to maintaining patient records addressed several medico-legal issues.

Telementoring. A practical option in surgical training

BACKGROUND

Telemedicine offers significant advantages in bringing consulting support to distant colleagues. There is a shortage of surgeons trained in performing advanced laparoscopic operations.

AIM

Our aim was to evaluate the role of telementoring in the training of advanced laparoscopic surgical procedures.

METHODS

Student surgeons received a uniform training format to enhance their laparoscopic skills and intracorporeal suturing techniques and specific procedural training in laparoscopic colonic resections and Nissen fundoplication. Subsequently, operating rooms were equipped with three cameras. Telestrator (teleguidance device), instant replay (to critique errors), and CD-ROM programs (to provide information of reference) were used as intraoperative educational assistance tools. In phase I, four colonic resections were performed with the mentor in the operating room (group A) and four colonic resections were performed with the mentor on the hospital grounds, but not in the operating room (group B). The voice and video signals were received at the mentor's location, using coaxial cable. In phase II, two Nissen fundoplications were performed with the mentors in the operating room (group C) and two Nissen fundoplications were performed with the mentors positioned five miles away from the operating room (group D), using currently existing land lines at the T-1 level.

RESULTS

There were no differences in the performances of the surgeons and outcome of the operations between groups A & B and C & D. It was possible to tackle the intraoperative problems effectively.

CONCLUSIONS

The telementoring concept is potentially a safe and cost-effective option for advanced training in laparoscopic operations. Further investigation is necessary before routine transcontinental patient applications are attempted.

In situ hybridization studies of metalloproteinases 2 and 9 and TIMP-1 and TIMP-2 expression in human prostate cancer

The expression of MMP-2, MMP-9, TIMP-1, TIMP-2, and the urokinase receptor were examined in fetal and normal prostate tissues, benign prostatic hyperplasia and prostate cancer (n = 117). In situ hybridization with digoxigenin-labeled oligonucleotide probes demonstrated that TIMP-1 and TIMP-2 were expressed at elevated levels in the stroma of Gleason sum 5 tissues, whereas MMP-2 and MMP-9 were expressed at relatively low levels. In higher Gleason sum tissues (GS 8-10), TIMP-1 and TIMP-2 were not expressed, whereas MMP-2 and MMP-9 were intensely expressed. Furthermore, TIMP-1 and TIMP-2 expression was high in organ-confined specimens (OC, n = 43), somewhat lower in specimens with capsular penetration (CP, n = 29), and low or negative in samples with surgical margin/seminal vesicle (M/SV, n = 17) and lymph node (LN, n = 13) involvement. In contrast, MMP-2 and MMP-9 expression was low in the OC tissues; and noticeably higher in CP, M/SV, and LN specimens. Finally, correlation of TIMP and MMP expression with GS and pathological stage versus cure rate further revealed that a high percentage of organ-confined, GS 5 specimens expressing TIMP and little MMP were cured. In comparison, few of the GS 7-10 patients with capsular penetration and expressing MMP and little TIMP were cured. The data suggest that TIMP-1 (and TIMP-2) and MMP-2 (and MMP-9) are independent predictors of outcome.

Soybean (Glycine max) agglutinin binds to corneal endothelial cells during wound repair and alters their microfilament pattern

In the present study we have examined soybean (Glycine max) agglutinin (SBA) binding to cells of the rat corneal endothelium during wound repair. Circular transcorneal freeze injuries were given to the endothelia and the tissues were organ cultured at 37 degrees C in basal media Eagle with 10% serum for up to 72 hrs. SBA failed to bind to the surface of non-injured corneal endothelium, but strongly bound to cells involved in the wound repair process. Punctate surface binding was detected 24 hrs. post-injury, but stronger binding was observed at 48 hrs. after wounding. In this case, binding appeared to be distinctly distributed around the cell periphery. To investigate SBA binding during wound repair, endothelia were cultured in the presence of SBA (100 and 200 micrograms/ml). Cell migration into the wound area, and hence subsequent wound repair, was not affected at these concentrations. However, both concentrations altered cell morphology and microfilament patterns. Phalloidin staining of cells 24 hrs. after injury revealed that microfilaments appeared thinner and less in number. In addition, distinct aggregations of actin-positive material were detected at cell-to-cell contacts. Cells around the tissue periphery do not partake in the repair process but displayed an SBA concentration dependent fragmentation of their circumferential microfilament bundles. At 48 hrs. post-injury, SBA-treated cells within the wound area, unlike their control counterparts, did not exhibit stress fibers. These results suggest that a SBA binding surface component is associated with the reorganization of actin during corneal endothelial wound repair, and that these cells can migrate across their natural basement membrane without the benefit of a highly organized microfilament cytoskeleton.

Molecular pathology of primary and metastatic ductal pancreatic lesions: analyses of mutations and expression of the p53, mdm-2, and p21/WAF-1 genes in sporadic and familial lesions

BACKGROUND

The molecular pathology underlying the development and progression of ductal pancreatic adenocarcinoma is poorly understood relative to that of other major cancers in industrialized societies. The frequency, nature, and distribution of p53 abnormalities, their temporal relationship to the metastatic and clinicopathologic phenotypes of sporadic and familial pancreatic cancer, and their consequent effects on the genetics and expression of critical wild-type p53-regulated genes (mdm-2 and p21/WAF-1) warrant examination in pancreatic adenocarcinoma. This molecular and immunochemical study of the p53, mdm-2, and p21/ WAF-1 genes and gene products examined the largest series of nonneoplastic, neoplastic, and metastatic ductal pancreatic lesions reported to date in relation to clinicopathologic profile.

METHODS

Histologically confirmed specimens of primary (n = 136) and metastatic (n = 23) sporadic and familial ductal pancreatic adenocarcinoma lesions were subjected to immunochemical analyses of p53 expression in which a panel of 3 antibodies was utilized. A panel of nonneoplastic but histologically abnormal pancreatic lesions (n = 77) from individuals with varied histories of cigarette smoking were subjected to similar immunohistochemical examinations. In addition, 3 specimens from patients with chronic pancreatitis, 2 specimens of normal fetal pancreata, and 16 specimens of normal adult pancreata were examined as control tissues. Suitable frozen and archival microdissected tumor lesions were evaluated for mutations in exons 4-9 of the p53 gene by single strand conformation polymorphism (SSCP) and dideoxy sequencing analyses in which two distinct sets of outer and nested intron-based amplification primers were used for each exon. A subset of 25 tumor specimens and 18 tumor-derived cell lines for which the p53 mutation status was known were examined for amplification and/or overexpression of the mdm-2 gene; amplification was determined by Southern hybridization and overexpression by immunohistochemical and Western blot analyses. Similarly, mutations in the coding region of p21/WAF-1 gene were examined by SSCP and DNA sequence analyses, and steady-state expression of the p21/WAF-1 protein was assessed by Western blot analysis in these subsets of tumors and tumor-derived cell lines.

RESULTS

Positive ductal nuclear p53 immunostaining was demonstrated in 56% of primary tumors and 54% of metastatic lesions. The frequency did not differ significantly between sporadic and familial lesions, and immunostaining was not observed in ductal, acinar, or islet cell elements of normal pancreata or histologically abnormal benign pancreatic lesions from cigarette smokers. A total of 70% of tumor samples revealed reproducible SSCP abnormalities for p53; 42% of these were found in exons 7 and 8. DNA sequence analysis of cases with greater than 35% epithelial cellularity (n = 25) revealed 17 missense mutations, 12 of which were transitions. Seventy-five percent of these transitions were of G:C-->A:T type. A total of 22% of the p53 mutations identified were microdeletions, along with one insertional mutation at exon 8. None of the normal pancreata from sporadic or familial lesions revealed germ-line p53 alterations. Moreover, the frequency and spectra of p53 alterations exhibited no clear, statistically significant association with tumor grade, TNM stage, or patients' cigarette-smoking histories. The mdm-2 gene was neither amplified nor overexpressed immunochemically in a subset of ductal adenocarcinomas, and there was no clear relationship between the p53 mutation status and the status of the mdm-2 gene or protein. Similarly, SSCP and DNA sequence analysis of the p21/WAF-1 gene revealed only 2 genetic abnormalities in a series of 25 primary tumors and 15 tumor-derived cell lines; 1 of the cell lines also revealed the absence of immunoreactive p21/WAF-1 protein...