Lamina lucida of basement membrane: an artefact

In tissues prepared with chemical fixation followed by conventional dehydration, basement membranes have been observed to be laminated structures composed of a lamina lucida and lamina densa as well as a poorly limited transitional zone referred to as the pars fibroreticularis. Scattered attempts in the application of new techniques of tissue preparation such as cryofixation or freeze substitution for the study of the basement membrane structure have been made in recent years. From these studies, the possibility has arisen in which basement membranes are composed of only the lamina densa without a lamina lucida. In recent studies in this laboratory, the attempt was made to determine whether or not this lamina lucida is an artefact, and if so, which step in the conventional method of tissue preparation is responsible for its formation. Basement membranes from diverse sources in the mouse and rat including the testis, ductus epididymis, eye, thyroid, kidney, and skin, were observed after either cryofixation by slam freezing followed by freeze substitution, or aldehyde fixation followed by freeze substitution. The basement membranes after preservation with either of these two methods were composed of only the lamina densa with no lamina lucida. It indicates that an artefactual formation of the lamina lucida occurs during dehydration in conventional tissue preparation rather than during chemical fixation. In view of the well known superiority of freeze substitution over conventional dehydration, the lamina lucida of the basement membrane is likely to be an artefact. Therefore, it is concluded that the lamina lucida is an artefact formed during conventional tissue preparation, and in its original condition in the living state, the basement membrane is composed of a single layer made up of lamina densa material.     

Combination of subcutaneous abdominal wall retraction and optical trocar to minimize pneumoperitoneum-related effects and needle and trocar injuries in laparoscopic surgery

BACKGROUND: Both pneumoperitoneum and blind needle and trocar insertion may cause complications: because of the well-known physiological effects, CO2 insufflation is not indicated in patients with impairment of cardiorespiratory function and high-risk patients; injuries to underlying viscera and vessels by needles and trocars have been reported even when the open technique is used. METHODS: A technique which combines abdominal wall suspension by a new subcutaneous lifter (LaparoTenser) and optical trocar (OptiView) insertion has been evaluated in a random series of 22 patients undergoing various laparoscopic procedures. The optic trocar was inserted without previous insufflation, but low-pressure (1-5 mmHg) pneumoperitoneum was associated during the course of the procedure in 16 cases. RESULTS: The exposure of the operating field was good or sufficient in 21 cases (95%), while the placement of the optical trocar was always safe. One complication related to the insertion of the subcutaneous needles of the wall lifter occurred (suprafascial hematoma). CONCLUSIONS: The subcutaneous retractor allows the use of conventional cannulae and the combination of abdominal wall suspension with or without low-pressure pneumoperitoneum, thus enhancing the quality of exposure with no effect on the hemodynamic and respiratory functions.     

Evaluation of cervical nodal necrosis in nasopharyngeal carcinoma by computed tomography: incidence and prognostic significance

PURPOSE: The purpose was to study the prognostic value of contrast-enhanced computed tomography (CT) nodal necrosis in nasopharyngeal carcinoma. PATIENTS AND METHODS: One hundred sixty-one patients with newly diagnosed nasopharyngeal carcinoma and nodal metastases were reviewed. Forty patients also received cisplatin-based neoadjuvant chemotherapy in addition to radiotherapy. Nodal necrosis was defined as presence of hypodense areas in more than 33% of the node. Nodal response rate to chemotherapy, overall nodal control rate, local control rate, distant failure rate, overall relapse-free survival rate, and overall and cause-specific survival rates were compared between patients with and without nodal necrosis. Multivariate analysis was also performed. RESULTS: The incidence of nodal necrosis was 22.9%. Overall nodal response rates to chemotherapy were 88.9% (8/9) in patients with nodal necrosis and 74.2% (23/31) in those without. No significant differences in nodal control rate, local control rate, distant failure rate, and overall and cause-specific survival rates were found. Five-year overall relapse-free survival rate was lower in patients with cervical nodal necrosis (36%) as compared with those without (53%, p = .04). Multivariate analysis, however, did not confirm cervical nodal necrosis to be an independent prognostic factor. CONCLUSIONS: Presence of nodal necrosis in nasopharyngeal carcinoma does not affect nodal response to chemotherapy and nodal control by radiotherapy with or without chemotherapy. Cervical nodal necrosis does not appear to be an independent factor in predicting treatment outcome. Further studies to correlate nodal density with oxygenation status as well as tumor cell kinetics are warranted.     

Extended operations after induction therapy for stage IIIb (T4) non-small cell lung cancer

Twenty-three patients with stage IIIb (T4) non-small cell lung cancer received induction chemotherapy (median, 2 cycles) with (n = 12) or without (n = 11) radiation (median, 45 Gy) before operation. Nine tumors involved the carina (n = 8) or lateral tracheal wall (n = 1), 11 were located centrally and invaded the proximal pulmonary artery (n = 6), veins (n = 3), or both (n = 2), three were apical tumors involving T4 structures, and six were associated with histologically diseased mediastinal nodes. Five complete and 18 partial responses were observed after induction treatment. Resection of all residual tumor at the primary site and involved vestiges was possible in 21 patients (91%); in two apical tumors, tumor was left behind. Nine right tracheal sleeve and 11 intrapericardial pneumonectomies and three resections of apical tumors were performed; 11 patients (48%) had radical mediastinal lymph node dissection. Complete sterilization of the primary tumor was observed in 3 patients (13%). Mean operating time was 209.3 +/- 86.8 minutes, and mean blood loss was 896.9 +/- 1031 mL. Major postoperative complications occurred in 6 patients (26%), including hemothorax requiring drainage (n = 1) or reoperation (n = 1), acute distress syndrome (n = 2), and bronchopleural fistula (n = 2), and their incidence was significantly higher (p = 0.0003) among patients receiving induction chemoradiation than among those receiving chemotherapy alone (42 versus 9%). Early (< 1 month) postoperative mortality was 8.6% (n = 2). With a median follow-up of 25 months (range, 12 to more than 39 months), the projected 3-year overall survival was 54%.(ABSTRACT TRUNCATED AT 250 WORDS)     

Pharmacological classification of adenosine receptors in the sinoatrial and atrioventricular nodes of the guinea-pig

Factors influencing the change in bone mineral after 3 mo of lactation were investigated in 47 breast-feeding mothers, 11 formula-feeding mothers, and 22 nonpregnant, nonlactating control subjects. At 6-8 wk postpartum, the breast-feeding group had a mean (+/-SD) calcium intake of 34.8+/-13.2 mmol/d and breast-milk volume, calcium concentration, and calcium output of 0.865+/-0.230 L/d, 7.41+/-1.25 mmol/L, and 6.41+/-2.00 mmol/d, respectively. There was no relation between calcium intake and any breast-milk variable. Dual-energy X-ray absorptiometry of the whole body, spine, hip, and forearm was performed at 0.5 and 3 mo. There were significant decreases in bone mineral content at the spine (3.96%; 95% CI: 4.86%, 3.06%), femoral neck (2.39%; 95% CI: 3.61%, 1.17%), total hip (1.51%; 95% CI: 2.45%, 0.60%), and whole body (0.86%; 95% CI: 1.29%, 0.43%) in breast-feeding mothers but not in formula-feeding mothers or nonpregnant, nonlactating women. These changes were not related to calcium intake, breast-milk calcium concentration, vitamin D-receptor genotype, postpartum weight change, or use of the progesterone-only contraceptive pill. After adjustment for bone area, breast-milk volume and height were identified as significant predictors at the spine, such that greater decreases were associated with taller mothers (P = 0.007) and those with greater breast-milk volume (P = 0.001). This finding suggests that the marked bone mineral changes observed in breast-feeding mothers represented a physiologic response to lactation that was independent of dietary calcium supply.     

Triplet pregnancy in premature ovarian failure after oocyte donation and in vitro fertilization: a case report and review of literature

Oocyte donation in premature ovarian failure patients has become an extended indication for In Vitro Fertilization (IVF) procedure. Here the first case report is presented in Taiwan, R.O.C. of a triplet pregnancy in a patient with premature ovarian failure. After an adequate hormonal replacement therapy with oral premarin and intramuscular progesterone for endometrium preparation, the transfer on D15 of four embryos (with donated oocytes and IVF) resulted in implantation of three. Pregnancy support was provided also by oral premarin and intramuscular progesterone until the tenth week of gestational age (GA). The patient received Caesarean section at 35 weeks GA with delivery of three healthy babies weighing 2530 gm, 2420 gm, and 1810 gm respectively on Aug. 17, 1990.