Mechanical strength of single microcapsules determined by a novel micromanipulation technique

A micromanipulation technique has been developed to measure the bursting force of single dry microcapsules coated onto a surface, such as those normally used in carbonless copying paper. For measuring the bursting force of a given microcapsule, a single fine probe with a flat end about 10 microns in diameter was used to squeeze the microcapsule against a flat surface until it burst. The force being imposed on the microcapsule was measured by a transducer connected to the probe. The bursting force and diameter of single dry microcapsules in two samples, different in size and wall thickness, were measured by this technique. The bursting force of the microcapsules in one sample ranged from 50 to 220 microN and the diameter from 1.3 to 7.0 microns, whilst the bursting force in the other was from 20 to 175 microN and the diameter from 0.7 to 3.7 microns. This technique makes it possible to compare the mechanical strength of microcapsules made of different formulations, and to infer information about microcapsule mechanical properties.

Effects of hypophysectomy and growth hormone administration on the mRNA levels of collagen I, III and insulin-like growth factor-I in rat skeletal muscle

The effect of short-term treatment of normal or hypophysectomized rats with biosynthetic growth hormone (GH) was studied in extensor digitorum longus and soleus muscles. In situ hybridization revealed that in normal rats, mRNA for collagen I, collagen III and insulin-like growth factor-I (IGF-I) are expressed by fibroblasts between the muscle fibre areas and that the specificity of this location was not altered by GH administration. Hypophysectomy appeared to cause a decrease in IGF-I and decreased collagen I and III gene expression (P < 0.001, P < 0.001, respectively). GH administration seemed to increase IGF-I mRNA levels in all the animals studied. Quantitative image analysis that GH administration to hypophysectomized rats caused an increase in collagen I gene expression after 2 days (P < 0.05) and an increase in collagen III gene expression after 4 days (P < 0.05). The results indicate that the fibroblast cells are an important target for the action of GH on skeletal muscle and that the fibroblasts respond to GH by increases in the expression of mRNA for collagen I and collagen III.

Prevention of dexamethasone-induced insulin resistance by metformin

This study investigates the effect of the antidiabetic drug metformin on dexamethasone-induced hyperglycaemia and insulin resistance in mice. Normal mice were treated with dexamethasone (2.5 mg/kg/day p.o.) plus metformin (250 mg/kg/day p.o.) and pair-fed to those receiving dexamethasone alone. Metformin reduced the extent of dexamethasone-induced hyperglycaemia and decreased insulin resistance as indicated by an improved insulin-hypoglycaemia test. Metformin-treated mice also showed increased basal glucose uptake into isolated diaphragm (by 38%), soleus (by 19%) and deep (red) quadriceps (by 31%). Measurements in the quadriceps showed that the increase in glucose uptake occurred without increasing either the mRNA levels or total cellular membrane abundance of the GLUT1 or GLUT4 glucose transporter isoforms. Thus metformin can ameliorate dexamethasone-induced hyperglycaemia and insulin resistance in part by increasing glucose disposal into skeletal muscle. Since this was achieved in quadriceps muscle without increasing mRNA or total membrane abundance of GLUT1 or GLUT4, it is possible that metformin might influence the intrinsic activity of glucose transporters, as well as altering their intracellular translocation.

Nutritional evaluation of two agroindustrial by-products for ducks and pigs

Forty-eight male White Pekin ducks and 24 crossbred barrows (Landrace or Yorkshire sows; PIC Line 355 boars) were used in three experiments to evaluate the nutritional value of two by-products generated from agricultural industries. In each experiment, test ingredients consisted of a dried meat solubles product (DMS) from swine processing facilities and a yeast fermentation product (YFP) from a commercial source. Soybean meal (SBM) with a CP content of 48% served as the control ingredient in the three experiments. Different batches of each by-product were evaluated in the three experiments utilizing an apparent ME (AME) assay for poultry (Exp. 1 and 2) and a digestibility assay for barrows (Exp. 3). The nitrogen-corrected AME (AMEn) for SBM, DMS, and YFP in Exp. 1 were 2.909, 2.801, and 3.292 kcal, respectively. The AMEn for SBM, DMS and YFP in Exp 2 were 2.809, 3.207, and 3.565 kcal, respectively. In Exp. 3, diets were formulated such that the test ingredients provided the sole source of amino acids in each experimental diet. The AME of SBM, DMS, and YFP in Exp. 3 were 3.844, 2.208, and 3.552 kcal, respectively. Based on the results of the ME assay for poultry, the DMS product compares well to SBM and seems to be suitable for feeding to ducks. The YFP does not seem to be suitable for feeding nonruminant species based on poor ability to support nitrogen retention in both species (-36% and -20% in Exp. 1 and 2, and 20% in Exp. 3).

Dependence of penicillium chrysogenum growth, morphology, vacuolation, and productivity in fed-batch fermentations on impeller type and agitation intensity

The influence of the agitation conditions on the growth, morphology, vacuolation, and productivity of Penicillium chrysogenum has been examined in 6 L fed-batch fermentations. A standard Rushton turbine, a four-bladed paddle, and a six-bladed pitched blade impeller were compared. Power inputs per unit volume of liquid, P/VL, ranged from 0.35 to 7.4 kW/m3. The same fermentation protocol was used in each fermentation, including holding the dissolved oxygen concentration above 40% air saturation by gas blending. The mean projected area (for all dispersed types, including clumps) and the clump roughness were used to characterize the morphology. Consideration of clumps was vital as these were the predominant morphological form. For a given impeller, the batch-phase specific growth rates and the overall biomass concentrations increased with agitation intensity. Higher fragmentation at higher speeds was assumed to have promoted growth through increased formation of new growing tips. The mean projected area increased during the rapid growth phase followed by a sharp decrease to a relatively constant value dependent on the agitation conditions. The higher the speed, the lower the projected area for a given impeller type. The proportion by volume of hyphal vacuoles and empty regions decreased with speed, possibly due to fragmentation in the vacuolated regions. The specific penicillin production rate was generally higher with lower impeller speed for a given impeller type. The highest value of penicillin production as well as its rate was obtained using the Rushton turbine impeller at the lowest speed. At given P/VL, changes in morphology, specific growth rate, and specific penicillin production rate depended on impeller geometry. The morphological data could be correlated with either tip speed or the "energy dissipation/circulation function," but a reasonable correlation of the specific growth rate and specific production rate was only possible with the latter. Copyright 1998 John Wiley & Sons, Inc.

Concurrent cisplatin, prolonged oral etoposide, and vincristine plus chest and brain irradiation for limited small cell lung cancer: a phase II study of the Southwest Oncology Group (SWOG-9229)

PURPOSE

The primary objectives of the study were to evaluate the efficacy and safety of prolonged oral (PO) etoposide as part of cisplatin-based chemotherapy plus concurrent chest/brain irradiation induction, followed by CAV consolidation, in the treatment of patients with limited-stage small cell lung cancer (SCLC-LD) within a cooperative group setting.

METHODS AND MATERIALS

Fifty-six eligible patients with SCLC-LD received three 28-day cycles of cisplatin 50 mg/m2 i.v. (days 1, 8; 29, 36; and 57, 64), PO etoposide 50 mg/m2 (days 1-14, 29-42, and 57-70), and vincristine 2 mg i.v. (days 1, 29, and 57). Thoracic irradiation (TRT) was administered at 1.8 Gy in 25 daily fractions to a total dose of 45 Gy via an AP:PA arrangement, to begin concomitantly with induction chemotherapy. Prophylactic cranial irradiation (PCI) was started on day 15 of induction therapy. Fifteen daily fractions of 2.0 Gy were administered to the entire brain to a total dose of 30 Gy to finish at approximately the same time as TRT. Two 21-day cycles of consolidation cyclophosphamide 750 mg/m2 i.v., doxorubicin 50 mg/m2 i.v., and vincristine 2 mg i.v. (all on days 1 and 22), were given beginning on day 106 or week 16, from the start of induction therapy.

RESULTS

Among 56 eligible patients, 93% had SWOG performance status 0-1. All had adequate organ function and had not received prior therapy. The overall confirmed response rate was 46%, including 16% complete responders and 30% partial responders. After a minimum follow-up duration of 17 months, the Kaplan-Meier median progression-free (PFS) and overall survival (OS) were 10 and 15 months, respectively. Two-year survival is 28%. Only 28 of 56 patients (50%) completed chemotherapy per protocol, while 52 of 56 patients (93%) completed radiation per protocol. Eleven patients (20%) discontinued secondary to toxicity and two patients died from treatment. The major toxicity was hematologic. The two deaths were secondary to infection. Of the nonhematologic toxicities, there were 10 cases of pulmonary fibrosis (including one Grade 3) and six cases of pneumonitis (including one Grade 3).

CONCLUSION

Concomitant chemoradiation with oral etoposide as part of a platinum-based chemotherapy and TRT induction regimen is toxic. The CR rate is not better than our prior best group-wide experience. The progression-free and overall survival are similar to published trials utilizing short-course i.v. etoposide. As in chemotherapy for extensive-stage SCLC, there is no apparent advantage to prolonged exposure to etoposide, and toxicity resulted in an inferior therapeutic index compared to programs with shortened exposure.

Characterisation of mycelial morphology using image analysis

Image analysis is now well established in quantifying and characterising microorganisms from fermentation samples. In filamentous fermentations it has become an invaluable tool for characterising complex mycelial morphologies, although it is not yet used extensively in industry. Recent method developments include characterisation of spore germination from the inoculum stage and of the subsequent dispersed and pellet forms. Further methods include characterising vacuolation and simple structural differentiation of mycelia, also from submerged cultures. Image analysis can provide better understanding of the development of mycelial morphology, of the physiological states of the microorganisms in the fermenter, and of their interactions with the fermentation conditions. This understanding should lead to improved design and operation of mycelial fermentations.

Endothelial dysfunction in streptozotocin-diabetic rats is not reversed by dietary probucol or simvastatin supplementation

Oxidative stress and dyslipidaemia are key features of diabetes mellitus and may be involved in mediating the vascular endothelial dysfunction associated with this disease. The aim of this study was to examine the effect of dietary lipid-lowering and antioxidant agents on vascular endothelial function and oxidative stress. Diabetic male Sprague-Dawley rats (i.v. streptozotocin, 45 mg/kg) were fed for 4 weeks on a standard diet or on a diet supplemented with either the lipid-lowering antioxidant probucol (1% w/w in diet) or the 3-hydroxy 3-methylglutaryl coenzyme-A (HMG-CoA) reductase inhibitor simvastatin (0.01% w/w in diet). Responses to noradrenaline, acetylcholine, and sodium nitroprusside were assessed in small mesenteric arteries (mean internal diameter 300+/-5 microm, n = 80) mounted on a small vessel myograph. Plasma concentrations of total cholesterol and triglycerides were significantly raised in standard-fed diabetic rats and significantly reduced in probucol and simvastatin-fed diabetic rats 8-epi-prostaglandin (PG)F2alpha, an indicator of oxidative stress, was raised in liver and aorta from diabetic rats compared to controls. Probucol supplementation reduced 8-epi-PGF2alpha in aorta and liver of diabetic rats but increased 8-epi-PGF2alpha content in plasma and aorta from control animals. The abnormal relaxation to acetylcholine in arteries from the diabetic rats (pEC550 diabetic 6.763+/-0.172 vs control 7.541+/-0.175; p < 0.05) was not improved by probucol or simvastatin. These data, therefore, do not support a role for oxidative stress or dyslipidaemia in mediating the impaired ACh-induced endothelium-dependent relaxation of small mesenteric arteries from the streptozotocin-diabetic rat.

Dietary antioxidant supplementation reduces lipid peroxidation but impairs vascular function in small mesenteric arteries of the streptozotocin-diabetic rat

Impaired endothelium-dependent relaxation could underlie many of the vascular complications associated with insulin-dependent diabetes mellitus, and may be mediated by increased oxidative stress. The effect of antioxidants on vascular endothelial function and oxidative stress of streptozotocin-diabetic rats was assessed by dietary supplementation with vitamins E and C. Diabetic (i.v. streptozotocin, 45 mg/kg) male Sprague-Dawley rats were fed one of six supplemented diets containing 75.9, 250, or 500 mg vitamin E/kg chow, 250 mg vitamin C/kg H2O, 250 mg vitamin E/kg chow plus 250 mg vitamin C/kg H2O, or chow deficient in vitamin E, and then compared to standard-fed control rats. After 4 weeks, small mesenteric arteries were dissected and mounted on a small vessel myograph, concentration response curves were then constructed to noradrenaline, acetylcholine and sodium nitroprusside. Acetylcholine-mediated relaxation was impaired in arteries from diabetic rats (pEC50 6.701+/-SEM 0.120, n = 8) compared to controls (7.386+/-0.078, n = 6; p < 0.05). The 500 mg/kg vitamin E diet further impaired maximum relaxation to acetylcholine (58.2+/-10.5 vitamin E, n = 7 vs 84.4+/-5.3 % standard, p < 0.05), and the combined vitamin E plus C diet impaired maximum relaxation to sodium nitroprusside (48.5+/-4.1 in vitamin E + C, n = 8 vs 75.6+/-3.9 % standard; p < 0.01). However, plasma 8-epi-prostaglandin (PG)F2alpha (measured as an estimate of oxidative stress) was dose-dependently decreased in rats on vitamin E supplemented diets. Dietary antioxidant supplementation did not reverse impaired endothelial function in this model of uncontrolled diabetes despite a concomitant decrease in oxidative stress.

Flow-induced dilatation in isolated resistance arteries from control and streptozotocin-diabetic rats

Acetylcholine-induced vasodilatation is impaired in animal models of insulin-dependent diabetes mellitus (IDDM), and may result from altered nitric oxide synthesis or release. The response to intraluminal flow, a more physiologically relevant stimulus for nitric oxide release, is unknown. This study examined flow-induced responses in isolated resistance arteries from male Sprague-Dawley control and streptozotocin-diabetic (45 mg/kg i.v., 4 week duration) rats. Mesenteric arteries (4-5th order) were dissected and cannulated on a pressure myograph (mean internal diameter +/- SEM at 40 mmHg, control 223 +/- 8, n = 9 vs diabetic 239 +/- 12 microm, n = 8, NS). Arteries were preconstricted with noradrenaline (1 micromol/l) and intraluminal pressure raised and maintained at 80 mmHg. Luminal flow was raised in incremental steps (0-1.27 microl/s). Arteries from control animals dilated to flow while arteries from diabetic animals constricted (% change in internal diameter +/- SEM at 0.79 microl/s: control 13.46 +/- 6.52, n = 9 vs diabetic -7.44 +/- 3.38%, n = 8; p < 0.005). Incubation with N(omega)-nitro-L-arginine methyl ester (0.1 mmol/l) abolished flow responses in arteries from controls but not from diabetic rats. In conclusion, impaired flow-induced nitric oxide-mediated vasodilatation may contribute to vascular disease in IDDM.

Biology of esophageal cancer and the role of combined modality therapy

1. The biology of esophageal cancer involves multifactorial environmental and genetic events. 2. The understanding of the clinical significance of molecular markers is rapidly evolving. 3. Combined-modality approaches should still include surgery in good performance status (ECOG scale < or = 2) patients. 4. Neoadjuvant chemoradiation is probably better than surgical resection alone for patients with potentially curable disease, but only validation of this approach by CALGB-9781 can justify this as a new "proven" standard-of-care in the United States. 5. A pathologic complete response to neoadjuvant therapy is the strongest predictor of long-term survival. 6. 5-FU, by either short course or protracted continuous infusion, comprises the backbone of combination chemotherapy in combined-modality design. 7. Radiation therapy should be given at standard 1.8 to 2 Gy/fraction without a scheduled break. 8. Only by enrolling sufficient numbers of patients in prospective clinical trials will clinicians be able to further define the optimal sequencing and actual necessity of each individual component of combined-modality therapy.

Detection and cellular localization of heparin-binding epidermal growth factor-like growth factor mRNA and protein in human atherosclerotic tissue

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a member of the epidermal growth factor family which binds to and activates the epidermal growth factor (EGF) receptor. HB-EGF mRNA is expressed by monocytes and vascular smooth muscle cells (VSMC) in culture, and has been shown to be a potent VSMC mitogen in vitro. The aim of this study was to screen normal and human atherosclerotic arteries and SMC cultured from these arteries for expression of HB-EGF, and to determine its cellular localization in human lesions. Using the highly sensitive technique of reverse transcription polymerase chain reaction (RT-PCR), we screened biopsies taken from normal human vessel walls and atherosclerotic tissue, for expression of HB-EGF mRNA. Northern blotting and RT-PCR were employed to determine levels of HB-EGF gene expression in SMC, cultured from normal and atherosclerotic arteries. Cellular localization of mRNA and protein, within human atherosclerotic plaques, was assessed using in situ hybridization with 35S labelled riboprobes, and immunohistochemistry with polyclonal antibodies specific for human HB-EGF. HB-EGF mRNA was found to be expressed in human atherosclerotic lesions and in VSMC cultured from these lesions. Expression of HB-EGF could not be detected in quiescent aortic VSMC using Northern blotting, but was highly up-regulated in these cells after treatment with basic fibroblast growth factor (bFGF) for 24 h. Although HB-EGF mRNA was detected in all vascular tissue examined using RT-PCR, in situ hybridization and immunohistochemistry revealed expression of HB-EGF in small portions of diseased arteries only. Immunohistochemistry showed strong staining for macrophages in all areas of HB-EGF expression. No association of HB-EGF with SMC was observed in any of the specimens examined. In conclusion, HB-EGF, a potent mitogen for VSMC, is expressed by macrophages in human.

Concomitant intraarterial cisplatin, intravenous 5-flourouracil, and split-course radiation therapy for locally advanced unresectable pancreatic adenocarcinoma: a phase II study of the Puget Sound Oncology Consortium (PSOC-703)

A Gastrointestinal Tumor Study Group (GITSG) protocol showed a survival benefit for patients with locally advanced unresectable pancreatic adenocarcinoma when treated with split-course radiation therapy and bolus intravenous (i.v.) 5-fluorouracil (5-FU) as compared with survival achieved with radiation alone. In an attempt to improve these results, a phase II trial using intraarterial (i.a.) cisplatin, systemic-infusional 5-FU, and concomitant split-course radiation therapy was conducted. Sixteen previously untreated patients with unresectable pancreatic adenocarcinoma (5 with American Joint Committee on Cancer [AJCC] stage I-II, 11 with stage III) disease were treated with i.a. cisplatin 100 mg/m2 by selective celiac arteriography followed by i.v. infusional 5-FU 1,000 mg/m2/day for 4 days, and concomitant split-course external beam photon radiation therapy at 2.0 Gy for 10 days in a 12-day period. After a planned 14-day interval, the identical chemoradiation treatment was repeated; finally, after a second 2-week interval, a third cycle of chemotherapy with a final 10 Gy radiation was administered. All 16 patients were evaluable for response; there were two partial responses (PR: 12%) and five minor responses (31%). Median follow-up period was 77 months. Median time to progression was 6 months (range 1-12 months), and median survival was 9 months (range 4-94 months). Nausea/vomiting was the major toxicity. There were no treatment-related fatalities. This regimen of concomitant i.a. cisplatin, i.v. infusional 5-FU, and split-course external beam photon radiation is well tolerated but has minimal activity in the treatment of locally advanced unresectable pancreatic adenocarcinoma. Future combined-modality protocols for this disease should explore alternative chemoradiation schemes.

Upregulation of IGF-I and collagen I mRNA in human atherosclerotic tissue is not accompanied by changes in type 1 IGF receptor or collagen III mRNA: an in situ hybridization study

BACKGROUND

Immunoreactive insulin-like growth factor-I (IGF-I) has recently been localized to vascular smooth muscle cells in coronary atherectomy plaques, but it remains unclear whether these cells are the source of this growth factor. We therefore investigated the gene expression of this factor, and the expression of the genes for its receptor and two types of collagen known to be regulated by IGF-I, in vascular tissue samples from patients with atherosclerosis or restenosis.

METHODS

Gene expression and localization were investigated by in situ hybridization, using 35S-labelled complementary RNA probes specific for IGF-I, its type a receptor, collagen I, and collagen III. The cellular composition of the tissue samples was determined by immunohistochemistry using antibodies specific for smooth muscle cells and macrophages.

RESULTS

IGF-I and collagen I messenger RNAs were found in areas containing smooth muscle cells and macrophages, but collagen III and type 1 IGF receptor gene expression could not be detected in any tissue samples.

CONCLUSION

IGF-I appears to be involved in the progression of the atherosclerotic plaque, even at an advanced stage, but preliminary data from two restenotic plaques indicate that it may not be involved in the later stages of restenosis.

IGF-I increases bFGF-induced mitogenesis and upregulates FGFR-1 in rabbit vascular smooth muscle cells

Insulin-like growth factor-I (IGF-I) and basic fibroblast growth factor (bFGF) have both been implicated in the abnormal proliferation of vascular smooth muscle cells (VSMC) that occurs after injury to the arterial wall in vivo. We have investigated the effects of these growth factors on proliferation of rabbit aortic smooth muscle cells (RASMC) in vitro. IGF-I, in contrast to bFGF, is a weak mitogen for RASMC. However, when IGF-I (10 ng/ml) was added in combination with bFGF for 24 h, the effect of the two growth factors on DNA synthesis was synergistic at all concentrations tested (P > 0.001 compared with summed values of bFGF alone plus IGF-I alone), and this synergy was also observed at the level of RASMC proliferation (P < 0.001). Time-course experiments indicated that although bFGF was able to stimulate DNA synthesis after 16 h, activity peaked at 24 h, and a synergistic response with IGF-I was not observed before 24 h. Northern blot analysis demonstrated that IGF-I (10 ng/ml) could selectively upregulate fibroblast growth factor receptor-1 (FGFR-1) mRNA 4.0 +/- 0.24-fold (P < 0.001) without a significant effect on FGFR-2, and this induction in FGFR-1 mRNA occurs in a time- and dose-dependent manner. In addition, IGF-I increases FGFR-1 protein levels in RASMC 2.7 +/- 0.12-fold (P < 0.01), as demonstrated by Western blotting, and this upregulation occurs before the peak in DNA synthesis. These results suggest that IGF-I may be capable of increasing the responsiveness of VSMC to bFGF through modulation of FGFR-1.

Applications of image analysis in cell technology

Image analysis is now a well established complement to optical microscopy, allowing routine quantification of microscopic observations. Recent method developments include location and enumeration of bacteria in solid foods, in situ microscopy and image analysis for on-line monitoring of yeast fermentations, and texture analysis of fungal colonies for subsequent transfer. Notable recent applications include studies on the pulsatile growth of hyphal apices, biochemical differentiation of fungal colonies, and simple structural differentiation of mycelia from submerged fungal cultures.

Growth hormone increases IGF-I, collagen I and collagen III gene expression in dwarf rat skeletal muscle

The effect of short-term treatment with biosynthetic growth hormone (GH) of male dwarf rats was studied in EDL and soleus muscles. In situ hybridisation revealed that in the untreated dwarf rat collagen I, collagen III and insulin-like growth factor-I (IGF-I) mRNA is mainly expressed by fibroblasts between the muscle fibre areas. Quantitative image analysis showed that, 8 h after a single GH injection, the level of mRNA for all three genes increased compared to the untreated dwarf animal. IGF-I mRNA levels were similar in normals and untreated dwarf rats but significantly increased 8 h after a single GH injection in EDL (P < 0.01) and soleus (P < 0.001). In untreated dwarf rats, collagen I and III gene expression was significantly less than in normal animals (P < 0.001). Collagen III gene expression also increased significantly 8 h after a single GH injection, in both muscles (P < 0.01). Collagen I gene expression showed significant increases 8 and 24 h after GH treatment in EDL (P < 0.01), although the increases seen in soleus did not reach significance. The effects of multiple GH injections (one, two or four) did not appear to be additive. The results of the time course studies are consistent with an intermediary role for IGF-I in the production of collagen in muscle.

Radiation therapy for sarcoid of the thalamus/posterior third ventricle: case report

There are a limited number of previously reported cases involving the use of radiation therapy for sarcoid of the brain. The case of a 22-year-old man with a thalamic/posterior third ventricle sarcoid mass that grew despite steroid medication is presented. The patient was treated with external beam radiation to a total dose of 20 Gy, with 2-Gy fractions over 14 elapsed days. A complete radiographic response was achieved 4 months after radiation was completed. Radiographic follow-up through 8 months postradiation shows no evidence of disease recurrence. Fractionated radiation therapy in low-to-moderate doses appears to be efficacious in steroid-refractory sarcoid of the brain.

Bidirectional placental transfer ('leak') of L-glucose in control and diabetic rats

The placental transfer of D- and L-glucose was investigated in anaesthetised non-diabetic and streptozotocin-induced diabetic rats. Maternal to fetal transfer was determined by perfusing the fetal side of one placenta in situ whilst infusing a mixture of D-[3-3H]glucose and L-[1-14C]glucose into the maternal circulation. Back-transfer from the fetal to maternal circulation was assessed by determining the uptake of the radiolabelled glucoses from the perfusion fluid during a single passage through the placenta on the fetal side. Maternal diabetes resulted in a reduced utero-placental blood flow but an increased bidirectional transfer of D-glucose. Non-specific maternal to fetal placental transfer of L-glucose was greater in diabetic rats than in controls, and the loss of L-glucose during placental perfusion on the fetal side was, again, greater in diabetic than in control rats. This increased bidirectional 'leak' of glucose possibly reflects a functionally compromised placenta, caused by its formation in a diabetic milieu, and may explain the greater fetal-maternal glucose ratios found in diabetic rats relative to controls.

Carcinoma of the male breast: update 1994

In many ways, male and female breast cancers are similar, but do have some notable differences. Although the underlying etiology of male breast cancer may be partially due to hormonal or environmental changes, this disease is rare compared to female breast cancer. Most often, it presents as a painless lump, with estrogen receptor-positive infiltrating ductal carcinoma being the most common pathologic type. The main component of local therapy is either a radical or a modified radical mastectomy, with adjuvant chemotherapy proving useful. Estrogen receptor-positive tumors respond well to hormonal therapy. More research is needed in order to: (1) further characterize the molecular biological properties of male breast cancer tumors, (2) further investigate the role of adjuvant chemotherapy, and define successful regimens, and (3) determine optimal chemotherapy regimens in the treatment of metastatic disease. As this disease is a relatively rare condition, whenever possible, all patients should be allowed to participate in national cooperative group studies.

Atrial natriuretic peptide-like (ANP-LIR) and ANP prohormone immunoreactive astrocytes and neurons of human cerebral cortex

Atrial natriuretic peptide (ANP) represents a family of related peptides originally isolated from cardiac atria that have potent natriuretic, diuretic, and vasorelaxant properties. ANP has previously been localized in neurons of the rat brain in regions subserving cardiovascular functions and fluid/electrolyte balance and has been localized in astroglia of the canine brain. To determine whether ANP is present in astrocytes of the human brain and to validate the canine model for future studies, human brain tissue was obtained from autopsy cases with no brain damage or neurological or vascular disease. Human brains were obtained less than 3 h postmortem, and anterior cingulate and striate cortices were dissected following perfusion or immersion fixation. Immunohistochemical processing utilized antibodies against the processed form of ANP (ANP IV, ANP104-128) and against rat proANP (amino terminus) and the avidin-biotin-peroxidase technique. Isolated, strongly ANP-immunoreactive protoplasmic astrocytes were observed in all layers of the cingulate and striate cortex gray matter. ANP-positive fibrous astrocytes were observed in the white matter. Additionally, distinctive immunopositive astrocytes were found both within and immediately subjacent to the glia limitans. Antibody against the prohormone stained only protoplasmic astrocytes and sublimitans astrocytes and processes. In addition to the astroglia, ANP was detected in scattered multipolar neurons in the cerebral gray matter. These results provide additional evidence for diversity of peptide localization in astrocytes and suggest roles for ANP in the local regulation of cerebral blood flow, blood-brain barrier permeability, or cerebrospinal fluid volume.