Biomedical subjects
Publications and source records attributed to R Tiwari.
Fetus in fetu is a rare condition not usually considered in the differential of a neonatal abdominal mass. This article illustrates the importance of prenatal ultrasound in the treatment of this condition as it facilitated the assembly of a multispecialty healthcare team that intervened within days of birth.
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Fusarium head blight (FHB) of wheat is a widespread and destructive disease which occurs in humid and semi-humid areas. FHB epidemics can cause serious yield and quality losses under favorable climatic conditions, but the major concern is the contamination of grains with mycotoxins. Resistance to FHB is quantitatively inherited and greatly influenced by the environment. Its evaluation is costly and time-consuming. The genetic basis of FHB resistance has mainly been studied in spring wheat. The objective of this study was to map quantitative trait loci (QTLs) for resistance to FHB in a population of 240 recombinant inbred lines (RILs) derived from a cross between the two Swiss winter wheat cultivars Arina (resistant) and Forno (susceptible). The RILs were genotyped with microsatellite and RFLP markers. The resulting genetic map comprises 380 loci and spans 3,086 cM. The 240 RILs were evaluated for resistance to FHB in six field trials over 3 years. Composite interval mapping (CIM) analyses carried out on FHB AUDPC (i.e. mean values across six environments) revealed eight QTLs which altogether explained 47% of the phenotypic variance. The three main QTLs were mapped on the long arms of chromosomes 6D ( R(2)=22%), 5B ( R(2)=14%) and 4A ( R(2)=10%). The QTL detected on 5B originated from the susceptible parent Forno. Other QTLs with smaller effects on FHB resistance were detected on chromosomes 2AL, 3AL, 3BL, 3DS and 5AL.
Implantation of blastocysts involves conversion of maternal and embryonic cell surfaces from a nonadhesive to an adhesive state in response to the internally driven developmental program or to externally generated factors. However, the intricacies of the cellular and subcellular changes that promote the attachment are not known, because these changes are difficult to determine in situ because of the nonaccessibility of the site. To overcome this, an in vitro model of implantation was developed by co-culturing rat blastocysts and uterine epithelial cells of the same gestational age (day 5 postcoitum; plug day as day 1) in drops hanging from the lid of a Petri dish. The system was used to study the changes on the surface membranes of the cells of the trophectoderm and uterine epithelium and to evaluate the antiadhesive activity of the newly designed test substances. The isolated epithelial cell vesicles were co-cultured with zona-free blastocysts in the microdrops (40-50 microl) hanging from the lid of a 60-mm Petri dish. The lid was placed over the lower dish, which was presaturated with the medium. The culture was examined 48 h later to determine the site of adhesion of epithelial cell vesicles with the trophoblasts lining the blastocyst. The cell-cell adhesion was monitored on a computerized image analyzer. To validate the adhesion of blastocysts and epithelial cell vesicles in co-culture, the expression of a cell adhesion molecule, uvomorulin, was studied using immunocytochemical technique after incubating with antiuvomorulin antibody. Intense staining was noted on the membrane surfaces at the site of attachment of the blastocyst and cell vesicles.
Structural modifications in iridoid glycosides and evaluation of their efficacy on adhering capability (in vitro) of immature hamster uterine epithelial cells to the substratum have been studied. Out of 31, eight compounds in vitro, five compounds in utero and two in vivo showed adhesion/implantation preventing activity, respectively. The results provide an indication for further exploration in the line of development of anti-adhesive agents.
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BACKGROUND: Medical records of 43 patients with histologically proved diagnosis of squamous cell carcinoma who were treated between the years 1975 and 1994 at the department of Otolaryngology Head Neck Surgery, VU Amsterdam were examined. METHODS: Tumors were restaged according to UICC classification 1997. Thirty-eight patients were treated for cure, nine were treated with chemotherapy followed by external beam radiotherapy, and 28 patients were treated with surgery followed by postoperative radiotherapy. No patient was lost to follow-up. Data with respect to survival were analyzed. RESULTS: Eighty-three percent of the tumours were in stage III or stage IV at the time of first presentation. Five-year survival after surgery and postoperative radiotherapy for all patients was 64%. For stages II, III, and IV it was 83%, 49%, and 37%, respectively. Cervical nodal metastases were present in 4.1% at the time of presentation. Thirty-seven percent of the patients survived 2 years after chemotherapy followed by radiotherapy. CONCLUSIONS: Squamous cell carcinoma continues to be diagnosed late. Surgery followed by radiotherapy remains the treatment of choice. Mandibulotomy should be considered for better clearance of retromaxillary space in T3 -T4 tumors. The eye should be preserved whenever it is oncologically safe to do so.
BACKGROUND: To evaluate the outcome after surgery and radiotherapy for extensive nodal disease in patients with primary head and neck cancer. METHODS: Between 1973 and 1995, 77 from a total of 1398 patients had histopathologic evidence of positive margins in 85 neck dissection specimens for squamous cell carcinoma of the oral cavity, oropharynx, larynx, or hypopharynx. Postoperative radiotherapy with a curative dose was given to 50 necks. Ipsilateral neck recurrence was defined as the relevant event, and cumulative survival distributions were estimated by the Kaplan-Meier method. Differences between groups were analyzed with the log rank test. RESULTS: Disease-free survival was 24.9% at 2 years, and disease-specific survival was 33.6% at 2 years. After restriction of the 50 patients who received postoperative curative radiotherapy, the time to neck recurrence was stratified according to irradiation dosage, with 62.5 Gy as the cutoff point. A statistically significant difference was found for patients treated with 62.5 Gy or more, with a regional control rate of 75.6% at 2 years (p <.036). CONCLUSIONS: The overall outcome after neck dissection with positive surgical margins is poor. Considerable improvement is achieved by postoperative radiotherapy treatment with dosages of 62.5 Gy or more.
The superior gingivolabial sulcus has not been recognised as a separate entity in the oral cavity for the localisation of carcinoma. These cancers are not uncommonly labelled as buccal carcinomas or as carcinomas originating from the superior alveolar process and sometimes as maxillary sinus carcinomas. Early symptoms of sensory disturbances are often missed. Although cervical nodal metastasis is not usual at first presentation, metastasis to parapharyngeal, retropharyngeal and nasolabial lymph nodes is known. This article presents the author's observations on carcinoma of the superior gingivolabial sulcus seen over a period of 4 years. Cancer at this site has poor prognosis. Despite aggressive treatment with radical locoregional surgery and postoperative radiotherapy, only one of nine patients survived 5 years.
OBJECTIVE: To evaluate the outcome of neck dissection for advanced metastasis and subsequent planned radiotherapy to the neck and primary tumor. STUDY DESIGN: Single-center, retrospective case series. METHODS: From 1988 to 1998, 37 previously untreated patients were included into the study protocol. Two had a single tumor-positive neck node and the remaining 35 had multiple tumor-positive neck nodes (mean number, 6.0). Extranodal spread was reported in 35 cases (95%); mean nodal size was 5.7 cm (SD, 2.4 cm). Five patients (14%) were not irradiated or were irradiated with palliative intention. Of the remaining patients, 30 received irradiation of 60 Gy or more to the neck and the primary tumor (mean dose, 66.9 Gy; SD, 4.2 Gy). Cumulative survival distributions were estimated by the Kaplan-Meier method, and differences between groups were analyzed with the log-rank test. RESULTS: Treatment-related mortality was observed in three patients (8%). Disease-specific survival was 49% at 2 years and the overall locoregional control rate was 43% at 2 years. Patients with T1 to T2 primary lesions were compared with those with advanced primary disease, and the 2-year local control rates were 76% and 47%, respectively (P = .056). The following prognostic factors were identified for distant metastasis: three or more positive nodes (P = .037), positive surgical margins in the neck dissection specimen (P = .004), and time from diagnosis until neck dissection of 23 days or more (P = .043). The influence of distant metastasis on disease-specific survival was evident (P = .0003). CONCLUSION: Patients with low-T-stage tumors have a better local control rate with this regimen and survival depends on the status of the neck.
UNLABELLED: BACKGROUND. Non-union of mandibulotomies is a serious complication but risk factors are unclear. No data are available on the effect of the specific dose of irradiation at the osteotomy site. METHODS: Forty-eight patients (36 men, 12 women, median age 58 years) undergoing a mandibulotomy and postoperative radiotherapy were enrolled in the study. Twenty-five had wire and 23 had plate osteosyntheses. Five patients had a non-union and three had minor complications. The distribution of the radiation dose and the specific dose at the mandibulotomy site were calculated. Parametric tests and logistic regression were used for analysis. RESULTS: Non-union was not related to a specific dose of irradiation at the osteotomy site. Also, no effect could be attributed to type of fixation. CONCLUSIONS: There is no evidence for a single factor, radiation, or fixation type, that contributes to a non-union. We recommend a careful surgical technique.
Pathological communication between the food and air passages in the neck region due to malignant disease is known. However, such a pathology arising as a result of a non malignant process is relatively uncommon, and only a handful of reports exists in the literature. The authors describe and discuss the management of two patients with laryngopharyngeal fistula of nonmalignant etiology.
Chondrosarcoma of the larynx is rare. The posterolateral lamina of the cricoid cartilage is the site most commonly involved. Although the symptomology, radiological and histopathological diagnostic features are well known, the condition continues to be diagnosed late and recurrences after excision are common. In general, radical surgical excision can result in long-term remission, although prognosis is related to the histopathological grade of the tumor. While a conservative surgical approach in low-grade tumors is justified, unexplained hoarseness, unilateral vocal cord paralysis and dyspnea requires CT scan examination.
AIMS: A retrospective study was carried out of 50 patients with carcinoma of the ethmoid, treated over a period of 20 years. METHODS: The treatment used was surgery, followed by post-operative external beam radiotherapy and when possible supplemented by brachytherapy. RESULTS: Although the nature of surgery in the majority of cases was conventional, the 63% 5-year overall survival, except in adenocarcinomas, was slightly better than that achieved by more aggressive surgery. There was no mortality and morbidity was minimal. CONCLUSIONS: Conventional surgery in combination with radiotherapy and brachytherapy gives satisfactory and comparable results.
BACKGROUND: The periorbita has been traditionally regarded as the decisive layer whose involvement in carcinoma of maxillary sinus indicates orbital exenteration. Anatomic texts depict that the orbital fat rests on the periorbita. Our experience at surgical dissections has been different. METHODS: Twenty-five patients underwent total maxillectomy for advanced (T3-T4) carcinoma of the maxillary sinus with postoperative radiotherapy during a 15-year period between 1981 and 1995. In 11 patients, despite radiologic evidence of orbital invasion, and in 5 patients with infiltration of the periorbita, the eye could be preserved without evidence of recurrence. In 6 patients who in addition underwent orbital exenteration, histopathologic evidence of tumor invasion of the orbit was present in only one surgical specimen. RESULTS: Clinicoanatomic studies have clearly shown the presence of a thin, distinct fascial layer which surrounds the periocular fat and separates it from the periorbita. Neither clinical examination nor imaging could predict orbital invasion with absolute accuracy. Histopathologic examination of the surgical specimens shows that tumor infiltration of the eye is rare. CONCLUSION: Periocular fat is surrounded by a thin fascial layer and is not in direct contact with the periorbita. Intraoperative decision making with respect to preservation of the eye is sometimes essential.
Surgical interventions on the infratemporal fossa require an accurate knowledge of the surgical anatomy. Thirty-four adult human skulls were examined and measurements made of the distance between the zygomatic arch and the root of the lateral pterygoid plate. The distance between the central part of the lateral and medial pterygoid plates was also measured. The first measurement represents the distance of the foramen ovale from the zygoma; the average being 38.2 mm. The average distance between the pterygoid plates is 9.6 mm. Addition of these two measurements represents the distance of the lateral wall of the nasopharynx from the zygoma and the average is 47.8 mm. Together with the knowledge of the arrangement of the muscle layers and the nerves and vessels in this region, this information has proved useful in the surgery of the area.
The purpose of this study was to measure DNA repair capacity and mutagen sensitivity in patients who have had three or more primary forms of cancer. It was hypothesized that, if abnormalities in DNA repair and mutagen sensitivity were cancer susceptibility factors, such findings would be seen with regularity in individuals with multiple primary cancers. DNA repair capacity was measured by determining repair of UV-irradiated plasmid DNA (pCMVCAT) transfected into peripheral blood lymphocytes. Results from 18 patients and a like number of age- and sex-matched controls demonstrated a significant difference in DNA repair capacity (P < 0.0001; odds ratio = 14). Mutagen sensitivity was measured by determining the mean number of chromatid breaks per cell after in vitro exposure to either bleomycin or 4-nitroquinoline-1-oxide. The difference in mean bleomycin- or 4-nitroquinoline-1-oxide-induced mutagen sensitivity between cases and controls was not statistically significant. Fourteen of the 18 patients had positive family histories of cancer; in 10, the history was compatible with cancer susceptibility syndromes. Although the numbers were small, there was no suggestion in this study that treatment or the presence of cancer was the cause of the DNA repair abnormalities encountered. These findings support the concept of diminished DNA repair capacity as an underlying feature in the development of a mutator phenotype.