The effect of somatostatin versus corticosteroid in the treatment of Graves' ophthalmopathy

Uncontrolled study has demonstrated the usefulness of somatostatin in the treatment of mild Graves' ophthalmopathy (GO). We performed a prospective study to evaluate the usefulness of somatostatin as compared to corticosteroid in the treatment of moderately severe GO. All patients were rendered euthyroid and observed for 3 months to exclude spontaneous improvement without active treatment. They were randomized to receive either somatostatin (SS, octreotide 200 micrograms q8h subcutaneously, n = 8) or corticosteroid (CS, prednisone 1 mg/kg/day in decreasing doses, n = 10). Assessments of soft tissue inflammation, exophthalmos, palpebral aperture, intraocular pressure, diplopia, cornea, and visual acuity were made every 4 weeks for 3 months. MRI of the orbit was performed before and after treatment. Both SS and CS therapy decreased the palpebral aperture and activity score after 3 months (p < 0.05), but those treated with CS had a lower activity score after treatment when compared to SS [2.5 (1-7) v.s. 3.5 (0-4), median (range), p < 0.05]. Only CS, but not SS, was able to reduce intraocular pressure and muscle size as documented by MRI, but no significant reduction in proptosis was observed in either group. Also, patients' self-assessments of the eye changes after treatment were similar between the two groups. Both groups showed significant elevation of urinary glycosaminoglycan (GAG) excretion before therapy (SS 24.6 +/- 10.8; CS 27.8 +/- 11.4 mg/24 h), which was reduced after treatment (SS 12.5 +/- 7.3; CS 10.8 +/- 6.3 mg/24 h, p < 0.05). However, no significant correlation could be observed between the degree of GAG reduction and the clinical outcome of the patients. In conclusion, the long acting SS octreotide was effective in reducing soft tissue inflammation and providing symptomatic relief in GO but not as effective as corticosteroid in reducing muscle size. In view of the minimal side-effects and similar efficacy as compared to corticosteroid in patients with minimal extraocular muscle enlargement, it is suggested that a trial of SS may be considered in selected patients with GO.

Cutaneous stoma in the roux limb of hepaticojejunostomy (hepaticocutaneous jejunostomy): useful access for intrahepatic stone extraction

A cutaneous stoma in the Roux limb of hepaticojejunostomy (hepaticocutaneous jejunostomy) was used for stone extraction in two children who had hepatolithiasis (14.5 and 15.5 years, respectively) after operation for choledochal cysts. In constructing the hepaticocutaneous jejunostomy, a short, straight proximal limb from the skin to the bilioenteric anastomosis is mandatory. It provides a pathway, superior to the T-tube tract, for repeated stone extraction, which can be performed under sedation, thus obviating repeat laparotomies. The stoma allows flexible choledochoscopy, balloon dilatation of intrahepatic duct strictures, and extraction of intrahepatic stones using grasping forceps, baskets, and balloons. The electrohydraulic lithotriptor may be applied to fragment larger stones.

Giant growth-hormone secreting pituitary tumour with extracranial extension

A 19 year old female patient with typical features of acromegaly was found to have an extensive pituitary tumour with suprasellar, lateral and inferior extensions. Magnetic resonance imaging (MRI) also showed a portion of the tumour extending from the right cavernous sinus through the foramen ovale to become extracranial. Serum growth hormone (GH) was 52.6 mU/L basally and remained elevated after oral glucose, confirming the diagnosis of acromegaly. Treatment with the long-acting somatostatin analogue, octreotide, for 6 months led to a 30% reduction in tumour volume of the intracranial portion but no effect on the extracranial and sphenoidal extensions. She was subsequently treated with trans-sphenoidal surgery followed by external irradiation. The possibility of perineural spread of the tumour was considered.

Low-molecular-weight heparin for the treatment of acute ischemic stroke

BACKGROUND

Despite doubts about their efficacy and concern about their safety, antithrombotic agents are often used to treat acute ischemic stroke. Recent experience in patients with other thromboembolic disorders suggests that low-molecular-weight heparin, which requires only subcutaneous administration once or twice daily, may be more effective and safer than standard (unfractionated) heparin.

METHODS

We conducted a randomized, double-blind, placebo-controlled trial comparing two dosages of low-molecular-weight heparin with placebo in the treatment of ischemic stroke. Patients were randomly assigned within 48 hours of the onset of symptoms to receive high-dose nadroparin (4100 anti-factor Xa IU twice daily), low-dose nadroparin (4100 IU once daily), or placebo subcutaneously for 10 days. The primary measure of outcome was death or dependency regarding activities of daily living six months after randomization. Secondary outcomes were death, hemorrhagic transformation of the infarction, and other complications at 10 days, and death or dependency at 3 months.

RESULTS

A total of 2750 patients were screened for the study. Among 312 patients randomized, 306 had outcomes that were analyzed at six months. Forty-five patients (45 percent) in the high-dose group, 53 patients (52 percent) in the low-dose group, and 68 patients (65 percent) in the placebo group died or became dependent. There was a significant dose-dependent effect among the three study groups in favor of low-molecular-weight heparin (P = 0.005 by the chi-square test for trend). No significant differences among the groups in the occurrence of secondary outcomes were observed at 10 days.

CONCLUSIONS

For patients with ischemic stroke treated within 48 hours of the onset of symptoms, low-molecular-weight heparin was effective in improving outcomes at six months.

Proteoglycans associated with the ciliary zonule of the rat eye: a histochemical and immunocytochemical study

The structural organization of integral and associated components of the ciliary zonule is still not fully understood. The present study is to localize and characterize the proteoglycans associated with the ciliary zonule of the rat eye by Cuprolinic blue (CB) staining and immunocytochemistry. After CB staining, the proteoglycans appeared as electron dense elongated rodlets and were localized with the zonular fibers. They were seen lying on the periphery of the zonular fibers or along the length of the individual fibrils. Most of the CB rodlets had a size of 60-170 nm long (average 130 nm) and 25 nm wide. Smaller CB rodlets measuring 25-60 nm long (average 45 nm) and 12 nm wide were sometimes found associated with the individual zonular fibrils. The CB rodlets were removed after chondroitinase ABC or chondroitinase AC treatment, but were resistant to heparitinase, nitrous acid, keratanase or Streptomyces hyaluronidase digestions. The ciliary zonule was also immunostained with three monoclonal antibodies: 2-B-6 specific for chondroitin 4-sulfate, 3-B-3 for chondroitin 6-sulfate and 1-B-5 for unsulfated chondroitin, using indirect immunoperoxidase or immuno-colloidal gold methods. The zonular fibers were immunoperoxidase stained and immunogold labeled by 2-B-6, but were not reactive to 3-B-3 and 1-B-5. The results demonstrate that chondroitin sulfate proteoglycan is associated with the ciliary zonule of the rat eye.

Direct coronal computed tomography of the upper cervical spine

STUDY DESIGN

The technique of obtaining direct coronal computed tomography images of the upper cervical spine is described.

OBJECTIVES

To show the usefulness of this technique in demonstrating upper cervical spine lesions and to show that orbital (lens) radiation dosage is minimal compared with conventional tomography.

SUMMARY OF BACKGROUND DATA

Conventional tomography is used routinely for assessment of the odontoid peg and upper cervical spine lesions. Direct coronal computed tomography for imaging the cervical spine has not been previously described.

METHODS

Using a removable head support device, direct coronal images are obtained using a computed tomography scanner. The gantry tilt is adjusted from the scanogram. Direct comparison of orbital radiation dosages between computed tomography and conventional tomography is made from placement of thermoluminescent dosemeter chips onto a phantom.

RESULTS

Direct coronal computed tomography provide superior demonstration of skeletal features in the upper cervical spine. Orbital radiation dose is negligible compared with conventional tomography.

CONCLUSION

This technique may replace conventional tomography in assessing of stable upper cervical spine lesions.

Magnetic resonance imaging of cerebrotendinous xanthomatosis

Cerebrotendinous xanthomatosis is a rare familial sterol storage disease with accumulation of cholestanol and cholesterol particularly in xanthomas, bile and brain. Magnetic resonance imaging is a useful modality for imaging the affected tissues. It contributes to the evaluation and management of the disease.

Pancreatic pleural effusion: an indication for emergency distal pancreatectomy and Roux-en-Y pancreatico-jejunostomy

A previously healthy 2-year-old boy was admitted because of shortness of breath, cough, and fever; there was minimal abdominal pain. He had recurrent right, followed by left pleural effusions, which contained markedly elevated amylase levels and high protein content. The pleural fluid amylase levels were disproportionately higher than the serum amylase levels. His abdominal signs were minimal. Surgical exploration showed a disruption of the proximal pancreatic duct. Distal pancreatectomy and Roux-en-Y pancreatico-jejunostomy were performed. After a complicated postoperative course he was discharged well and has remained so for more than 2 years.

Parapharyngeal teratoma in the newborn

A parapharyngeal teratoma in a newborn was the cause of acute respiratory distress, which was relieved by tracheostomy. Subsequent investigations by soft tissue x-rays of the neck, computed tomography, and examination under anesthesia defined the anatomic location of the tumor, its extent, and its likely nature. The tumor was removed completely by the transcervical approach. Mandibulotomy was not required. Histological examination showed the presence of a large amount of mature brain tissue, a moderate amount of collagenous fibers and smooth muscle cells, and a minute amount of cartilage and epithelial structures. The postoperative course was satisfactory. No recurrence was seen 6 years after surgery. The computed tomography scan was found to be the most useful investigative method. To the authors' knowledge, this is the first comprehensive report of a teratoma occupying the parapharyngeal space in a newborn.

Computed tomographic osteometry of the Asian lumbar spine

The computed tomography (CT) scans of 100 adult Chinese patients 18-60 years of age were studied to provide osteometric data on the Asian lumbar spine. The study population was composed of 63 men and 37 women. A total of 29 parameters were measured from each vertebral level. All the data were statistically analyzed for differences between men and women and left and right sides for paired structures. The data then were compared with data for white individuals where available. The results show that for Asians there is a significant sex difference (p < 0.001) for vertebral body and disk dimensions but not for the posterior elements or spinal canal. Compared with white individuals, Asians have a smaller vertebral body and a different spinal canal shape, with the lower part of the canal in relation to the vertebral body being narrowest. Such findings are of significance to the radiologist, to the surgeon, and in the design of instruments and implants for the Asian lumbar spine.

Computed tomographic osteometry of Asian lumbar pedicles

STUDY DESIGN

The lumbar pedicles of 100 adult Chinese patients were studied with computed tomography to provide data on their dimensions and angular alignment. Data obtained were compared with published measurements of spines from white patients to determine similarities and differences between the lumbar spines.

SUMMARY OF BACKGROUND DATA

The age range of the patients was 18 to 60 years. There were 63 men and 37 women. There was no demonstrable sex difference for dimensions or angular alignment of the pedicles.

METHODS

The method of scanning and measurement was standardized. Levels considered abnormal by the radiologist were excluded from the study, and a single observer was used to avoid inter-observer errors. The data obtained were statistically analyzed using Student's t test to determine differences between men and women and left and right sides. Age differences were analyzed using the F statistic test. The pedicle inclination angle (transverse angle) and the pedicle dimensions were compared with published data of whites.

RESULTS

The pedicles of Asians, when compared with those of whites, showed a similar pattern of changes with vertebral level. However, Asian pedicles had a larger pedicle inclination angle (transverse angle) from L1 to L4 (L1 = 16 degrees, L2 = 16 degrees, L3 = 19 degrees, L4 = 23 degrees), whereas L5 (29 degrees) was similar to many series of whites.

CONCLUSIONS

There are differences between the lumbar pedicles of Asians and whites. Such differences need to be considered when posterior pedicle screw fixation of the spine is performed.

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.

Evaluation of skull base erosion in nasopharyngeal carcinoma: comparison of plain radiography and computed tomography

Over a period of 16 months, a total of 175 patients with newly diagnosed nasopharyngeal carcinoma (NPC) were evaluated with plain radiography and computed tomography (CT) of nasopharynx and base of skull. 54 of 175 patients (30.9%) had CT evidence of skull base erosion. Plain radiography failed to demonstrate the skull base erosion in 22 of 54 patients (40.7%) and underestimated the extent of bony involvement in another 21 patients (38.9%). In 14 of 54 patients (25.9%), there was also false suspicion of bony erosion in the plain films in one or more regions of the skull base which was not substantiated by CT and subsequent clinical course. The present study shows that plain radiography lacks sensitivity and specificity in detecting skull base erosion by NPC. CT evaluation of NPC patients should include thin CT sections of base of skull for detection of subtle bone erosion, and this would allow better decision concerning the shielding of the pituitary-hypothalamic axis during radiotherapy for improvement in therapeutic ratio. For the investigation of individuals highly suspicious of harboring NPC, even when the plain radiography is negative, CT should still be performed as this may give the only clue to the presence of a small submucosally spreading NPC.

Venous sampling: its role in localization of endocrine tumours

Despite recent instrumentation advancement in morphologic imaging, venous sampling remains a sensitive physiological investigation for functional localization of hormonal hypersecretion. The test requires technical expertise and reliable laboratory support, and should be selectively applied to address individual clinical problems in coordination with other imaging modalities. Depending on the venous anatomy, sampling may achieve regional localization or lateralization of the endocrine tumour. Adrenal venous sampling serves to lateralize functioning tumour, and to differentiate it from hyperplasia. Inferior petrosal sinus sampling confirms pituitary Cushing's disease and lateralizes the adenoma. Systemic venous sampling identifies the site of ectopic hormonal secretion. In the localization of pancreatic islet cell tumours, the test is further enhanced by sampling after intraarterial injection of hormonal secretagogue. The experience of venous sampling in a regional referral hospital is discussed, including the patient selection, its technical details, pitfalls and effectiveness in achieving tumour localization for patient management.

Rectal perforation after barium enema in a patient with cytomegalovirus colitis--a case report

The very rare complication of rectal perforation during the barium enema of an immunocompetent Chinese man with cytomegalovirus (CMV) colitis is described. Rectal biopsy performed over three weeks earlier was unlikely to have been related to the perforation. Histopathological examination of the colonic mucosa showed features of active chronic colitis and CMV infection. After treatment with Ganciclovir, there was cessation of symptoms with eradication of the virus on repeat biopsy samples. It is suggested that presence of CMV colitis predisposed to rectal perforation. The clinical presentation, course of disease and response to treatment supported the concept of CMV as a primary aetiological agent. This complication should be borne in mind when performing barium enemas in patients with clinical features of colitis, especially if they are immunocompromised.

Treatment of acute cortical infarct with intravenous glycerol. A double-blind, placebo-controlled randomized trial

BACKGROUND AND PURPOSE

This clinical trial investigates the effectiveness of intravenous glycerol therapy in patients with acute cortical infarction in whom intracerebral hemorrhage was rigorously excluded.

METHODS

Within 48 hours of symptoms from their first ischemic stroke, 113 hospital inpatients were randomized into the trial, provided that hemorrhage was excluded by computed tomography and informed consent was obtained. Patients were stratified into alert, semicoma, and coma groups using the Glasgow Coma Scale. Treatment was allocated according to a double-blind, randomized protocol; 56 patients received 500 mL of 10% glycerol in saline over 4 hours on 6 consecutive days, and 57 patients received corresponding placebo treatment with saline. Using a variety of objective scoring systems, patient follow-up was up to 6 months.

RESULTS

Corresponding measures of outcome in the glycerol and placebo groups were similar. At 6 months, respective mortality rates were 17 of 56 and 16 of 57, and mean +/- SD improvements in scores were 9.98 +/- 14.40 vs 10.51 +/- 12.68 (long-term), 1.12 +/- 7.20 vs 1.57 +/- 6.30 (prognostic), -1.94 +/- 5.53 vs -2.06 +/- 5.34 (Glasgow Coma Scale), and 21.72 +/- 23.40 vs 11.94 +/- 18.10 (Barthel Index rating in survivors). Hemolysis (generally subclinical) was the only adverse effect.

CONCLUSIONS

There was no clinically or statistically significant difference in outcome between the groups; a trend toward greater functional recovery among survivors was evident after treatment with glycerol.

Computed tomography evaluation of neck node metastases from nasopharyngeal carcinoma

PURPOSE

To study the role of computed tomography in the pre-therapy evaluation of nasopharyngeal carcinoma.

METHODS AND MATERIALS

The computed tomography of 119 new patients of nasopharyngeal carcinoma were evaluated independent of clinical findings for neck node metastases, and then compared with clinical findings. Contrast enhanced axial scans were obtained at 5 mm intervals with the infraorbitomeatal line parallel to the gantry. Scans were obtained from the supra-sellar cistern to the C5 or C6 vertebra for the evaluation of the base of skull, nasopharynx, paranasopharyngeal space and the upper and mid neck.

RESULT

The present study confirmed the disparity of nodal extent documented by clinical palpation and computed tomography. Of the 37 patients who have no clinically palpable node (N0), computed tomography showed nodal involvement in 11 (29.7%) of them, and they were up-staged from N0 to N1. Computed tomography showed multiple or bilateral nodes in seven (58.3%) of the 12 patients with AJC N1 disease and they were hence up-staged to N2. All together, there were 28 (23.5%) patients who have no computed tomography evidence of nodal involvement by tumor. In agreement with clinical experience, the most commonly involved nodal groups were the upper internal jugular and upper spinoaccessary, followed by the lateral retropharyngeal. The percentage of nodes which were not clinically palpable was roughly the same for different regions (15-30%), except, as expected, that all the retropharyngeal nodes were not palpable. The risk of harboring retropharyngeal node was proportional to the size of the largest node in the ipsilateral neck.

CONCLUSION

A significant proportion of patients with clinically negative neck (N0) or AJC N1 disease will be upstaged by computed tomography, thus supporting its routine use in pre-therapy evaluation of nasopharyngeal carcinoma.

The basement membranes of cryofixed or aldehyde-fixed, freeze-substituted tissues are composed of a lamina densa and do not contain a lamina lucida

When tissues are processed for electron microscopy by conventional methods, such as glutaraldehyde fixation followed by rapid dehydration in acetone, basement membranes show two main layers: the electron-lucent "lamina lucida". (or rara) and the electron-dense "lamina densa". In an attempt to determine whether this subdivision is real or artefactual, two approaches have been used. Firstly, rat and mouse seminiferous tubules, mouse epididymis and associated tissues, and anterior parts of mouse eyes were subjected to cryofixation by instant freezing followed by freeze substitution in a -80 degrees C solution of osmium tetroxide in dry acetone, which was gradually warmed to room temperature over a 3-day period. The results indicate that, in areas devoid of ice crystals, basement membranes consist of a lamina densa in direct contact with the plasmalemma of the associated cells without an intervening lamina lucida. Secondly, a series of tissues from mice perfused with 3% glutaraldehyde were cryoprotected in 30% glycerol, frozen in Freon 22 and subjected to a 3-day freeze substitution in osmium tetroxide-acetone as above. Under these conditions, no lamina lucida accompanies the lamina densa in the basement membranes of the majority of tissues, including kidney, thyroid gland, smooth and skeletal muscle, ciliary body, seminiferous tubules, epididymis and capillary endothelium. Thus, even though these tissues have been fixed in glutaraldehyde, no lamina lucida appears when they are slowly dehydrated by freeze substitution. It is concluded that the occurrence of this lamina in conventionally processed tissues is not due to fixation but to the rapid dehydration. However, in this series of experiments, the basement membranes of trachea and plantar epidermis include a lamina lucida along their entire length, while those of esophagus and vas deferens may or may not include a lamina lucida. To find out if the lamina lucida appearing under these conditions is a real structure or an artefact, the trachea and epidermis were fixed in paraformaldehyde and slowly dehydrated by freeze substitution. Under these conditions, no lamina lucida was found. Since this result is the same as observed in other tissues by the previous approaches, it is proposed that the lamina lucida is an artefact in these as in the other investigated basement membranes. Thus, basement membranes are simply composed of a lamina densa that closely follows the plasmalemma of the associated cells.(ABSTRACT TRUNCATED AT 400 WORDS)

New methods of measuring vertebral rotation from computed tomographic scans. An intraobserver and interobserver study on girls with scoliosis

The purpose of this study was to search for constant and reliable reference points on the computed tomographic scans of scoliotic spines to measure vertebral rotation. Several methods using different sets of reference points on computed tomographic scans were tested for reliability. Two methods that gave minimum variation between the readings are presented here with interobserver and intraobserver reliability on 17 girls with adolescent idiopathic scoliosis. The selection of reference points for the two methods were as follows: In method 1, the vertebral rotation was an angle formed by two lines; one, a line joining the junction of the inner surfaces of two laminae and the midpoint of the posterior surface of the vertebral body and second, the vertical plane of the computed tomographic machine. In method 2, three datum points were marked; one at the junction of the inner surfaces of the laminae, and the other, one each at the junction of the inner surfaces of the lamina and the pedicle. A line bisecting this angle is drawn by the computer and the vertebral rotation was an angle between this line and the vertical plane. The 95% confidence intervals of these two methods for intraobserver variation were between 1.2 to 4.4 degrees. There was no significant difference between the readings obtained by each observer except on three occasions for observer 1. When these methods were tested for interobserver reliability, method 1 showed significant statistical differences between the readings obtained by the two observers. However, the readings obtained using method 2 were not significantly different between the two observers (95% confidence intervals = 3.2 to 5.8 degrees).(ABSTRACT TRUNCATED AT 250 WORDS)

Case report: pseudoarthrosis complicating ankylosing spondylitis--appearances on magnetic imaging

Development of typical pseudoarthrosis from an acute fracture in the spine of a patient with ankylosing spondylitis is documented by serial radiographs. The magnetic resonance imaging appearances of pseudoarthrosis are correlated with histological findings of the surgical specimen.

Case report: lingual thyroid, a cause of neonatal stridor

Stridor implies partial airway obstruction, resulting from intrinsic or extrinsic abnormalities of the upper respiratory tract. In a neonate whose airway is small, soft and easily occluded this may be potentially life threatening. Its immediate diagnosis with prompt therapy is a rewarding challenge. When stridor occurs in a neonate with congenital hypothyroidism, surgically amenable cause of obstruction due to an ectopic thyroid or thyroglossal cyst has to be seriously considered. We report a case of neonatal stridor caused by a lingual thyroid, and discuss the imaging approach.

Cryofixation of basement membranes followed by freeze substitution or freeze drying demonstrates that they are composed of a tridimensional network of irregular cords

Since conventional chemical fixation may extract tissue components and thus alter structural organization, cryofixation was used to reexamine the ultrastructure of three thick basement membranes: lens capsule, Reichert's membrane, and Engelbreth-Holm-Swarm (EHS) tumor matrix, and two thin basement membranes, those of epididymis and semi-niferous tubules. Cryofixation was achieved by slam freezing followed by either freeze substitution in dry acetone containing 1% osmium tetroxide and 0.05% uranyl acetate or freeze drying in a molecular distillation dryer. The results by both procedures demonstrate that thick basement membranes and the lamina densa of thin basement membranes are composed of a network of anastomosing strands referred to as cords. The cords vary in density and distinctiveness, but their thickness averages 3 to 5 nm in every tissue examined. The spaces separating the cords vary within wide limits, but their mean diameter is approximately 15 nm in every case. Two other common features are 1) the presence within the network of a few 1.5-3.0-nm-thick filaments and 2) 4.5-nm-wide sets of parallel lines referred to as double tracks. When these results are compared with those previously described after conventional fixation, no significant difference is observed in either the cord network or the associated filaments and "double tracks." However, in the thin basement membranes processed by cryofixation, the lamina densa is in direct contact with epithelial cells, whereas, after conventional fixation, the lamina densa is separated from the epithelial cells by a pale layer referred to as lamina lucida or lamina rara. Immunogold labeling of three basement membranes after cryofixation and freeze substitution in acetone containing 0.3% glutaraldehyde yields strong reactions for laminin, type IV collagen, and heparan sulfate proteoglycan. Comparison with previous results indicates that conventional formaldehyde fixation adequately preserves laminin and type IV collagen but causes the loss of some proteoglycan. It is concluded that, except for this loss and the absence of lamina lucida in cryofixed thin basement membranes, the morphological and antigenic features obtained after cryofixation are similar to those observed in the past after conventional fixation.

Effects of cis-4-hydroxy-L-proline on the androgen-induced growth of the lateral prostate of the prepubertally castrated guinea pig

The present study examined the effects of cis-4-hydroxy-L-proline (CHP), a proline analog, on the androgen-induced growth of the lateral prostate of prepubertally castrated guinea pigs. Prepubertal male guinea pigs were castrated at the age of 3 weeks and allowed to recover completely before subjection to an experimental regime to alter the stromal collagen synthesis by CHP. The animals were kept on a special proline-deficient diet (PDD) for a week before the subcutaneous injection of CHP (200 mg/kg/day) for 3 days, followed by a combined injection of CHP and dihydrotestosterone (DHT) (10 mg/kg/day) for 10 days. Control animals were injected with saline and DHT only. At the end of the experiment, the lateral prostate was removed and examined by 1) conventional transmission electron microscopy (TEM), 2) staining of proteoglycans (PGs) by Cuprolinic Blue (CB) using the critical electrolyte concentration (CEC) method, 3) carbohydrate and lectin histochemistry, and 4) electron microscopy (EM) lectin-gold labelling. The results showed that the wet weight of prostate from CHP-treated animals was significantly lower than the control and recovery groups. The epithelium was low columnar with an obvious increase in intercellular spaces and number of basal cells. The glandular cells showed little secretory activity with a decrease in number of granular endoplasmic reticulum (GER) profiles, secretory granules, and a small Golgi apparatus. The stroma was composed of stromal cells separated by large intercellular spaces with very sparse collagen fibrils, and a decrease in stromal PGs especially those PGs normally associated with collagen fibrils. CHP treatment also caused perturbation and disorganization in the epithelial basement membrane. The results suggested that stromal collagen is essential in mediating the response of glandular cells to DHT stimulation. Defective stromal collagens hamper the responsiveness of prostatic gland to androgen.