Biomedical subjects

J Hermans

Publications and source records attributed to J Hermans.

At least 361 records · Page 20Linked to original sources

PubMed1991

Watch and wait after careful surgical treatment and staging in well-differentiated early ovarian cancer.

Patients with well-differentiated epithelial ovarian cancer Stages Ia, Ib, Ic, and IIa (FIGO 1976) were observed after surgical treatment without adjuvant therapy. Careful surgical staging was required, and the extent of the staging procedure was assessed in each individual patient. There were 107 patients entered in the study by nine Dutch oncology centers. Of these 107, 21 did not fulfill all of the inlet criteria of the study and were excluded. Central pathologic review was performed in the remaining 86 cases, revealing that there was borderline tumor in seven patients, moderately or poorly differentiated tumor in nine patients, and tumor of nonepithelial histologic cell type in one patient. In two cases, no material for histologic review was available. After exclusion of these 19 cases, 67 patients were further analyzed. None of these 67 patients was lost during the follow-up period that ranged from 19 to 99 months (mean, 50 months). Tumor recurrence was found in four patients after 11, 25, 34, and 34 months of follow-up, all of whom died shortly after diagnosis of the recurrence without satisfactory response to secondary treatment. For the patients who underwent the most extensive staging procedure, disease-free 5-year survival was 100%. For the patients who were inaccurately staged, disease-free 5-year survival was 88%. It was concluded that well-differentiated early stage (Ia-IIa) ovarian cancer carries an excellent prognosis after surgical treatment and complete surgical staging, with the possible exception of patients with Stage Ic disease with malignant peritoneal washings. Furthermore, it was considered that the application of more objective and consistent ways of assessing tumor grade should be encouraged. Surgical staging should be regarded as the golden standard in defining subsets of low-risk patients and should be included and clearly defined in future trials on early ovarian cancer.

Adult↗

PubMed1991

Chronic mesenteric vascular syndrome. Results of reconstructive surgery.

Since 1961, 14 patients at the University Hospital of Leiden, the Netherlands, have undergone reconstructive surgery for treatment of chronic mesenteric vascular syndrome. Of the 42 mesenteric arteries, 31 were severely obstructed (mean, 2.2 stenotic arteries per patient). A total of 23 mesenteric arteries were repaired. Long-term follow-up data were available for all 13 surviving patients (mean follow-up, 11.8 years). Symptoms were relieved immediately after surgery, and relief was maintained during follow-up. Digital subtraction angiography at long-term follow-up evaluation was performed in eight patients (13 reconstructions) with these results: 11 (85%) of the 13 reconstructions were patent and severe stenoses were found in eight (33%) of the 24 mesenteric arteries (mean, 1.0 stenotic artery per patient). We conclude that reconstructive surgery for patients with chronic mesenteric vascular syndrome promptly relieves symptoms, provides excellent patency, and has long-lasting beneficial results.

Abdominal Pain↗

PubMed1991

Elimination of soluble 123I-labeled aggregates of IgG in patients with systemic lupus erythematosus. Effect of serum IgG and numbers of erythrocyte complement receptor type 1.

Using soluble 123I-labeled aggregates of human IgG (123I-AHIgG) as a probe, we examined the function of the mononuclear phagocyte system in 22 patients with systemic lupus erythematosus (SLE) and 12 healthy controls. In SLE patients, a decreased number of erythrocyte complement receptor type 1 was associated with less binding of 123I-AHIgG to erythrocytes and a faster initial rate of elimination of 123I-AHIgG (mean +/- SEM half-maximal clearance time 5.23 +/- 0.2 minutes, versus 6.58 +/- 0.2 minutes in the controls), with possible spillover of the material outside the mononuclear phagocyte system of the liver and spleen. However, multiple regression analysis showed that serum concentrations of IgG were the most important factor predicting the rate of 123I-AHIgG elimination. IgG concentration may thus reflect immune complex clearance, which in turn, would influence the inflammatory reaction, in SLE.

Adolescent↗

PubMed1991

Randomized study on the effect of collagen impregnation of knitted Dacron velour aortoiliac prostheses on blood loss during aortic reconstruction.

Intraoperative blood loss is an important factor in reconstructive surgery for aortoiliac disease because it is clearly associated with an increase in the operative morbidity and mortality rates. To minimize intraoperative blood loss, a blood-tight vascular prosthesis has been developed by impregnating a knitted Dacron prosthesis with bovine collagen. To study a potential reduction of intraoperative blood loss using these collagen-impregnated prostheses, we conducted a prospective randomized trial involving the collagen-impregnated prosthesis and its non-impregnated substrate, the Dacron knitted non-impregnated prosthesis. During a 2.5-year period, 123 consecutive patients (undergoing 81 procedures for aneurysmal disease and 43 procedures for occlusive disease) were admitted for elective aortic reconstructive surgery. Equal numbers of the two prostheses were randomly implanted. Various parameters were monitored: intraoperative blood loss before aortic cross-clamping (phase 1), during implantation of the prosthesis (phase 2) and after release of aorta cross-clamping (phase 3); the number of intraoperative and postoperative blood transfusions; and, finally, all preoperative and intraoperative factors that might contribute to intraoperative blood loss. A significant overall difference in intraoperative blood loss between the collagen-impregnated (1907 ml) and the non-impregnated (2425 ml) group was found (P = 0.003) [corrected]. However, this difference could not be attributed to collagen impregnation because no statistically significant difference in blood loss was found in the relevant period of operation (phase 3). Similar results were observed in patients operated on for both aneurysmal and occlusive disease (2600 versus 2195 ml and 2105 versus 1344 ml respectively).

Adult↗

PubMed1991

Flow cytometric analysis of DNA stemline heterogeneity in primary and metastatic breast cancer.

Flow cytometric DNA-ploidy analysis was used to investigate intratumor DNA stemline heterogeneity in primary breast carcinomas and lymph node metastases (LNM). The study was done in tumor specimens from 44 patients 35 of whom had LNM. In all, measurements were done in 214 different samples of primary tumors and 211 lymph nodes. Sixty-one percent (27/44) of the primary tumors were found to have multiple DNA aneuploid stemlines when the data of the separate samples per tumor (mean 4.9) were compared. Only five of 44 (11%) primary tumors were DNA diploid; two of these had DNA aneuploid metastases. Statistical analysis of these results indicated that, on average, four samples are needed for reliable determination of the DNA ploidy status of primary tumors by flow cytometry. In the majority of the cases (26/35), distinct tumor DNA stemlines found in LNM were also present in the primary tumor, which suggests that the generation of DNA ploidy diversity may have taken place prior to metastasis. Multiploidy was not related to tumor size but, particularly for LNM, was significantly correlated with age (r = 0.40, P = 0.02). The results of this study support the view that breast cancer is an extremely heterogeneous disease and that underestimation of this factor might account for the disagreement in literature about the prognostic value of DNA ploidy determinations.

Adenocarcinoma, Mucinous↗

PubMed1991

The choice between surgical resection and radiation therapy for patients with cancer of the esophagus and cardia: a retrospective comparison between two treatments.

The choice of treatment for patients with cancer of the esophagus and cardia is controversial. Since overall survival is poor, the most important aim of treatment should be improvement of the main complaint: the inability to eat. In a retrospective analysis of 265 patients, referred to the University Hospital in Leiden, The Netherlands, comparisons were made between palliative effects of surgical resection (N = 92) and irradiation (N = 128). Several methods of comparing surgery with irradiation are possible: (1) all surgical patients vs. all irradiated patients; (2) only those surgical patients who survived the operation (N = 70) vs. all irradiated patients (N = 128); and (3) survivors after resection (N = 70) vs. only those irradiated patients treated with "curative" radiation (N = 62). Analysis of prognostic factors showed that in both surgical and irradiated patients, the only statistically significant factor was the (dis)ability to eat. Criteria to be considered to make individual recommendations for either treatment are presented.

Adult↗

PubMed1991

Proline in alpha-helix: stability and conformation studied by dynamics simulation.

Free-energy simulations have been used to estimate the change in the conformational stability of short polyalanine alpha-helices when one of the alanines is replaced by a proline residue. For substituting proline in the middle of the helix the change in free energy of folding (delta delta G degrees) was calculated as 14 kJ/mol (3.4 kcal/mol), in excellent agreement with the one available experimental value. The helix containing proline was found to be strongly kinked; the free energy for reducing the angle of the kink from 40 degrees to 15 degrees was calculated, and found to be small. A tendency to alternate hydrogen bonding schemes was observed in the proline-containing helix. These observations for the oligopeptide agree well with the observation of a range of kink angles (18-35 degrees) and variety of hydrogen bonding schemes, in the rare instances where proline occurs in helices in globular proteins. For substituting proline at the N-terminus of the helix the change in free energy of folding (delta delta G degrees) was calculated as -4 kJ/mol in the first helical position (N1) and +6 kJ/mol in the second helical position (N2). The observed frequent occurrence of proline in position N1 in alpha-helices in proteins therefore has its origin in stability differences of secondary structure. The conclusion reached here that proline may be a better helix former in position N1 than (even) alanine, and thus be a helix initiator may be testable experimentally by measurements of fraction helical conformation of individual residues in oligopeptides of appropriate sequence. The relevance of these results in regards to the frequent occurrence of proline-containing helices in certain membrane proteins is discussed.

Alanine↗

PubMed1991

Effect of donor cornea preservation in tissue culture and in McCarey-Kaufmann medium on corneal graft rejection and visual acuity.

In a retrospective study the rate of rejection and clouding of the donor cornea for other reasons was investigated in 230 penetrating keratoplasties performed between 1984-1986. Donor corneas were stored in McCarey-Kaufmann Medium (MK) at 4 degrees C or in a modified Minimal Essential Medium (MEM) at 31 degrees C. No statistical differences in rejection rate, cloudiness due to other causes or visual acuity was found between MEM- and MK-stored donor corneas.

Adult↗

PubMed1991

Should all patients with malignant astrocytoma have postoperative radiotherapy?

A retrospective analysis was carried out on 96 patients with malignant astrocytoma treated during the period 1977--1986 to evaluate the contribution of postoperative radiation treatment to survival. In this material the initial Karnofsky performance score, age and extent of resection appeared to be prognostic factors, on the basis of which suggestions are given for selection of patients for radiotherapy.

Adult↗

PubMed1991

The accuracy of frozen section diagnosis of ovarian tumors.

We compared all frozen section examinations of ovarian tumors during a 6-year period in our institute with the final diagnosis from paraffin sections. In this period, 946 ovarian tumor specimens were removed for histologic assessment; 176 (18.6%) had frozen section examination. Final histological diagnosis was divided into benign (55.1%), borderline malignant (10.3%), and malignant (34.6%). Sensitivity of the frozen section method for malignant or borderline disease was 83.5% and specificity for a benign lesion, 92.8%. Predictive values and 95% confidence intervals were computed: 100% (93-100%) for malignancy, 62% (32-86%) for borderline malignancy, and 92% (85-96%) for a benign disease. Diagnostic problems occurred in large borderline tumors of mucinous cell type. Analysis of the 12 false negative diagnoses revealed that a sampling error was involved in 11 cases. A judgment error was made in the only false positive and in 1 out of 12 false negative frozen section diagnoses. It is concluded that when surgeons and pathologists are aware of the limitations of frozen section diagnosis of ovarian tumors, peroperative histologic examination can be worthwhile and prevent under- and overtreatment of gynecologic patients.

Adolescent↗

PubMed1991

The effect of supportive pamidronate treatment on aspects of quality of life of patients with advanced breast cancer.

Selective aspects of quality of life during supportive pamidronate (APD) treatment were assessed in breast cancer patients with osteolytic metastases. 144 patients were randomised to a pamidronate group (n = 76) or a control group (n = 68). A questionnaire measuring mobility impairment, bone pain, fatigue and gastrointestinal toxicity was administered at 3-monthly intervals. The analysis focused on changes in these quality of life domains over time. The median follow-up for both groups was 18 months. Mobility impairment and bone pain were significantly less in the pamidronate group as compared with the control group, due primarily to a rapid improvement shortly after initiation of pamidronate treatment. Thereafter, a gradual increase in these symptoms was noted in both groups. Gastrointestinal complaints and fatigue levels were similar over time in the two groups, suggesting that these symptoms are more dependent on disease-related events and cytotoxic treatment than on pamidronate treatment. The results indicate that reduced skeletal morbidity in breast cancer patients during pamidronate treatments is associated with an improvement in selective aspects of quality of life.

Activities of Daily Living↗

PubMed1991

DNA ploidy of primary breast cancer and local recurrence after breast-conserving therapy.

The value of DNA-flow cytometry and clinico-pathological prognostic factors for the prediction of local recurrences after breast-conserving therapy (BCT) were evaluated in a retrospective study. Thirty-one patients with a local recurrence were compared with 31 matched patients without a local recurrence. Morphology and DNA-indices of the local recurrences and their corresponding primary tumours were compared. Ductal carcinoma in situ was present significantly more often in the group with a primary recurring tumour, than in the matched group (P less than 0.001), and the same holds for lobular carcinoma (n = 5). Half of the tumours that recurred had macroscopically positive surgical margins compared to about one-fourth of the matched group. Fifty-six per cent of the DNA-aneuploid stemlines in cases with local recurrence were present in the corresponding primary tumour as well (confidence limits 45%-75%), an indication that the majority of local recurrences are true recurrences and not independently developed tumours. The lack of similarity of DNA stemlines between some primary DNA-aneuploid tumours and their local recurrences indicates that these tumours had developed independently. The percentage of DNA-aneuploid cases in the group with local recurrence (89%) did not differ significantly from that in the matched group (70%). However, the findings suggest a selective recurrence of DNA-diploid stemlines. This might indicate increased resistance of DNA-diploid tumour cells to radiotherapy as compared with the resistance level in DNA-aneuploid cells.

Aneuploidy↗

PubMed1991

DNA flow cytometry of hereditary and sporadic paragangliomas (glomus tumours).

Paragangliomas (glomus tumours) are benign, hypervascular tumours which in general are treated by surgical excision. The indication for treatment of these often slow-growing tumours needs additional criteria for predicting tumour progressiveness. For this reason the nuclear DNA content of 99 paragangliomas, 65 of them originating from patients with a positive family history, was analysed by flow cytometry. Unequivocal evidence of DNA aneuploidy was found in 37% of these clinically and histologically benign tumours, the average duration of follow up amounting to at least 10 years. The DNA index of the aneuploid tumours ranged from 0.90 to 2.03. No correlation was found between DNA ploidy and familiality or between DNA content and clinical criteria indicative of tumour progression, which means that DNA ploidy of these tumours cannot serve as a predictor for an expected growth pattern or familiality. DNA aneuploidy in hereditary and sporadic paragangliomas is not clinically related to malignancy, but indicates that these tumours are true neoplasias cytogenetically.

DNA, Neoplasm↗

PubMed1991

Extracorporeal renal artery reconstruction for renovascular hypertension.

Extracorporeal reconstruction can be applied to the successful repair of stenoses in the distal renal artery and its hilar branches. This study evaluates the short- and long-term results of extracorporeal renal artery reconstruction in 65 patients, including 5 children, with renovascular hypertension who were treated from 1974 through 1989. The mean age of the patients was 37 years (range, 7 to 67 years). The cause of the stenoses was arteriosclerosis in 8 patients, fibrodysplasia in 54 patients, and miscellaneous in 3. Hypertension was severe before treatment with a mean blood pressure of 187/147 mm Hg that was reduced to a mean of 159/102 mm Hg after medical therapy. Ten patients had renal dysfunction. Results were evaluated both at short-term intervals (mean, 7.9 months; 64 patients) and long-term intervals (mean, 5.9 years; 60 patients), after surgery. Blood pressure responses were classified as beneficial (cured/improved) or failures. Anatomic results were evaluated by angiography in 98% of the patients at the short-term interval and in 77% of the patients at the long-term interval. Extracorporeal renal artery surgery was performed on 78 kidneys among 65 patients (unilateral, 45 patients; bilateral, 13 patients; unilateral extracorporeal and contralateral in situ, 7 patients). In most of the cases autologous arterial graft was used for reconstruction. Early in the series one patient died as a result of the operative procedure (1/65, 1.5%). A beneficial blood pressure response occurred in 53 patients (53/65; 82%) at the short-term interval and in 49 patients (49/61; 80%) at the long-term interval, with the average blood pressure at the short-term interval being 138/85 mm Hg and at the long-term interval being 139/85 mm Hg. Renal function improved in all patients with preoperative renal dysfunction. Graft stenosis or occlusion of the main renal artery was neither observed at the short-term interval nor at the long-term interval. However, residual stenoses were observed in 9 of the 163 reconstructed distal branches (5.5%). Extracorporeal renal artery reconstruction with autologous arterial grafts can be effectively applied to lesions of the distal main renal artery and its hilar branches with durable functional results.

Adolescent↗

PubMed1991

Conformational equilibria of valine studied by dynamics simulation.

The conformational probability distribution of a valine residue in the valine dipeptide and of the valine side chain in an alpha-helix, as well as the change in helix stability for replacing alanine with valine, has been calculated by molecular dynamics simulations of explicitly hydrated systems: dipeptide, tetrapeptide and 10-, 14- and 18-residue oligoalanine helices. All computed free-energy differences are means from at least eight separate slow-growth simulations, four in each direction and are reported with their root-mean-square deviations. Different values for the change in free energy of folding (delta delta G degrees) have been calculated with the use of forcefields having an all-atom and a central-atom representation of methyl groups, etc. The value obtained with the all-atom forcefield agrees well with new experimental values (3 kJ/mol = 0.7 kcal/mol). Furthermore, the most stable valine side-chain rotamer in the helix is different for these two representations. The most stable rotamer for the all atom conformation is the same one that predominates for valines in alpha-helices in proteins of known conformation. The lower conformational freedom of the valine side chain in the helix contributes 1 kJ/mol to the difference in stability computed with the all-atom potential; unfavorable interactions of the side chain with helix, even in the most stable conformation, further increase delta delta G degrees.

Alanine↗

PubMed1991

Transformation of Mycobacterium aurum and Mycobacterium smegmatis with the broad host-range gram-negative cosmid vector pJRD215.

The transformation of Mycobacterium aurum and Mycobacterium smegmatis with the Gram-negative RSF1010-derived cosmid pJRD215 is described. The plasmid is stably maintained in both species and the antibiotic resistance determinants for kanamycin and streptomycin are expressed. Southern blot analysis shows that rearrangements take place both in M. aurum and in M. smegmatis. The use of pJRD215 in mycobacterial cloning systems is discussed.

Blotting, Southern↗

PubMed1991

Age at onset in Huntington's disease: effect of line of inheritance and patient's sex.

The Leiden Roster for Huntington's disease (HD) contained data on 2617 cases up to July 1988. The age at onset (AO) was known in 1084 cases and in 1020 of these both their AO and the sex of the affected parent was known. The mean AO was higher for females than for males and higher for maternal than for paternal cases. However, in the group born before 1925 only females with maternal inheritance had a higher mean AO. Data on influence of sex and line of inheritance were present for the grandparents as well as for the great grandparents. Influence of the line of inheritance from the grandparents was particularly present for the grandmother-father (MP) lineage; regarding the great grandparents a significant difference was found between the MPM and PMP lineage. The results obtained for juvenile HD cases were comparable to those previously published. In late onset cases (over 50 years) no maternal preponderance in inheritance was found.

Adult↗

PubMed1991

Allelotype of human breast carcinoma: a second major site for loss of heterozygosity is on chromosome 6q.

Loss of heterozygosity (LOH), which is detected with polymorphic DNA markers by comparing constitutional and tumor genotypes, has been observed at a number of different chromosome arms in primary breast tumors. These include 1p, 1q, 3p, 11p, 13q, 17p and 18q. We present here the results of a screening of all non-acrocentric chromosome arms, including those of the X chromosome, with at least one polymorphic marker per arm, in a total of 86 breast carcinomas. This dataset, termed an allelotype, indicates that in addition to the chromosome regions listed above, allelic loss may be observed in more than 30% of informative cases on 6q, 8q, 9q, 15q, and 16q. Multiple LOH involving at least two different chromosomes in a single tumor was observed in approximately 75% of the investigated tumors, and revealed complex chromosome involvement. Six different combinations of concurrent LOH at two different chromosome arms were found to be significantly correlated (r greater than 0.45; P less than 0.01). Tumors showing LOH at 3p or 17p were preferentially aneuploid, while LOH at 6q and 17q was inversely correlated with the number of positive lymph nodes and age respectively.

Alleles↗