Fine structure of pancreatic adenocarcinoma induced in rats by 7,12-dimethylbenz(a)anthracene.

We induced pancreatic adenocarcinomas in Long-Evans rats by placing crystals, 2-3 mg, of 7,12-dimethylbenz[a]anthracene (DMBA) in a 2- to 3-mm incision in the "head" of the pancreas approximately 1 cm from the duodenum. The incisions were closed with one or two silk sutures. The animals were killed 4-10 months after DMBA implantation, and nodules were removed and routinely prepared for light and/or electron microscopic study. Histologic organization varied from normal, through areas of tubule-like structures, to sheets of pleomorphic tumor cells. Electron microscopic study of tumor cells revealed large electron-lucent nuclei that frequently had irregular outlines and prominent nucleoli. The predominant feature of the cytoplasm was abundant rough endoplasmic reticulum. Zymogen granules were rare. Adjacent cells sometimes were jointed by an apical junctional complex to form a lumen into which projected irregular microvilli. A basal lamina sometimes occurred at the bases of the tumor cells. The fine structural similarity of these tumor cells to acinar cells was noted.     

Radioenhancement by cisplatin with accelerated fractionated radiotherapy in a human tumour xenograft

The aim of the present study was to investigate whether cisplatin would enhance the radioresponse of a human tumour xenograft when given in different schedules combined with accelerated fractionated radiation therapy. A human squamous carcinoma of the hypopharynx, FaDu, was grown in the thigh of athymic nude mice. Tumours were exposed to twice-daily 2-Gy fractions, applied 6 h apart over 2 weeks, 5 days a week, alone or combined with cisplatin given at maximally tolerated doses in three different schedules: (1) i.p. as a single bolus (SB) or (2) i.p. as a daily bolus at 30 min before the first daily radiation fraction or (3) s.c. as a continuous infusion through a mini-osmotic pump over 13 days, commencing 24 h prior to the first daily radiation fraction. The end point for the study was tumour growth delay (TGD), calculated as the difference between the delay in regrowth to 200% of the initial tumour size in treated versus control mice. SB cisplatin plus radiation showed only an additive effect on TGD, whereas daily-bolus and continuous-infusion cisplatin demonstrated a greater than additive effect when combined with accelerated fractionated radiation in this human tumour model. Cisplatin appears to be especially beneficial as a radiation enhancer when given throughout the course of radiation. Received: 15 December 1996 / Accepted: 25 March 1997     

Visual cortical projections and chemoarchitecture of macaque monkey pulvinar

We investigated the patterns of projections from the pulvinar to visual areas V1, V2, V4, and MT, and their relationships to pulvinar subdivisions based on patterns of calbindin (CB) immunostaining and estimates of visual field maps (P(1), P(2) and P(3)). Multiple retrograde tracers were placed into V1, V2, V4, and/or MT in 11 adult macaque monkeys. The inferior pulvinar (PI) was subdivided into medial (PI(M)), posterior (PI(P)), central medial (PI(CM)), and central lateral (PI(CL)) regions, confirming earlier CB studies. The P(1) map includes PI(CL) and the ventromedial portion of the lateral pulvinar (PL), P(2) is found in ventrolateral PL, and P(3) includes PI(P), PI(M), and PI(CM). Projections to areas V1 and V2 were found to be overlapping in P(1) and P(2), but those from P(2) to V2 were denser than those to V1. V2 also received light projections from PI(CM) and, less reliably, from PI(M). Neurons projecting to V4 and MT were more abundant than those projecting to V1 and V2. Those projecting to V4 were observed in P(1), densely in P(2), and also in PI(CM) and PI(P) of P(3). Those projecting to MT were found in P(1)- P(3), with the heaviest projection from P(3). Projections from P(3) to MT and V4 were mainly interdigitated, with the densest to MT arising from PI(M) and the densest to V4 arising from PI(P) and PI(CM). Because the calbindin-rich and -poor regions of P(3) corresponded to differential patterns of cortical connectivity, the results suggest that CB may further delineate functional subdivisions in the pulvinar.     

Variations in strategy for the treatment of urethral obstruction after a pubovaginal sling procedure

PURPOSE: We evaluated the success of several techniques for treating urethral obstruction and erosion after a pubovaginal sling procedure. MATERIALS AND METHODS: Between April 1998 and June 1999, 32 women 33 to 79 years old (average age 62) who underwent a pubovaginal sling procedure with various materials were referred for the assessment of urethral obstruction. Patients were evaluated with a urogynecologic history, physical examination, voiding diary, cystoscopy and video urodynamics. Surgical procedures to resolve urethral obstruction were performed transvaginally and the specific techniques used were based on the type of sling material, urethral erosion and concomitant stress incontinence or other urethral pathology. Outcome measures were assessed by disease specific quality of life questionnaires, voiding diary and urogynecologic questionnaire. RESULTS: Preoperatively 30 of the 32 women (93.7%) noticed urge incontinence, 20 (62.5%) performed intermittent self-catheterization, 6 (18.7%) had an indwelling catheter and 3 (9%) complained of concomitant stress urinary incontinence. After the sling takedown 29 patients (93.5%) achieved efficient voiding within week 1 postoperatively. Urge incontinence symptoms resolved in 20 cases (67%) but stress incontinence developed in 3 (9%). Of the 32 women 27 (84%) indicated that continence was much better than before the initial sling procedure. CONCLUSIONS: Managing urethral obstruction after a pubovaginal sling procedure is challenging. Using various techniques based on sling material, urethral erosion and bladder neck integrity a successful outcome is possible in the majority of cases.     

The effect of smoking on placental and fetal zinc status

Previous studies have reported a cadmium/zinc interaction in cadmium-exposed pregnant animals that results in (1) increased placental cadmium levels, (2) increased placental zinc levels, and (3) decreased placental zinc transport. This study was carried out to determine whether zinc status would be affected in pregnant women exposed to cadmium through cigarette smoke. Atomic absorption spectroscopy was used to determine the levels of cadmium and zinc; 65 pregnant women who smoke and 84 who do not smoke were studied. Our data reveal that increased cadmium levels in pregnant women as the result of smoking increase placental zinc levels and decrease cord red blood cell zinc levels. Significantly higher levels of both cadmium and zinc were found in the placentas of pregnant women who smoke; moreover, stepwise multiple regression showed that maternal whole blood cadmium levels predicted placental zinc levels. In regard to cord blood, a significant 9% decrease in the red blood cell zinc level was observed in infants of mothers who smoke and this decrease was correlated with smoking activity, as evaluated by measuring plasma levels of thiocyanate. Also cord red blood cell zinc levels were found to correlate with placental zinc levels in nonsmokers but not in smokers. Overall, our data show that a cadmium/zinc interaction does take place in the maternal-fetal-placental unit of pregnant women who smoke and results in less favorable zinc status in the infants.     

Endocrine profile of follicles containing oocytes with subsequent polyploid fertilization

In an attempt to identify oocytes at risk for polypronuclear fertilization, follicular fluids were obtained retrospectively that contained oocytes that fertilized normally and abnormally. Whenever possible, each patient served as her own control during the same stimulation cycle. Twenty-six of 169 patients had oocytes that became polypronuclear, and of those 26, 21 had oocytes that fertilized and cleaved normally. Follicular fluids were analyzed for estradiol, progesterone, androstenedione, transferrin, and insulin. Insulin levels were noted to be significantly elevated (P less than 0.05) in the polypronuclear group when compropose that insulin, a known growth factor for granulosa cells cultured in vitro, when present in excessive concentrations may predispose to polypronuclear fertilization.     

Specular microscopic and histologic observations in nonguttate corneal endothelial degeneration

Six phakic patients with unilateral corneal edema and clinically normal-appearing fellow eyes were examined with specular microscopy and found to have endothelial pleomorphism and reduced cell counts in the nonedematous cornea. None of these patients had any previous eye disease, trauma, inflammation, or surgery. Clinically unrecognized endothelial disease was proposed as a cause for the unilateral corneal edema and was verified by light and electron microscopic studies in five patients. These pathologic findings vary somewhat from those found in Fuchs' dystrophy and may represent either a variant or a form of endothelial cell degeneration of as yet undetermined etiology. Our studies suggest that this condition is not detectable in the nonedematous cornea by standard high magnification biomicroscopy and requires the use of the clinical specular microscope to confirm the diagnosis in suspected cases.