Showing papers by "University of Maryland, Baltimore published in 1981"

Mouse liver cell culture. I. Hepatocyte isolation.

Abstract: A method for isolation of mouse liver cells by a two-step perfusion with calcium and magnesium-free Hanks' salt solution followed by a medium containing collagenase is described. Several variations of the commonly used procedure for rat liver cell isolation were quantitatively compared with respect to cell yield and viability. The optimal isolation technique involved perfusion through the hepatic portal vein and routinely produced an average of 2.3 x 10(6) viable liver cells/g body weight. Optimal perfusate collagenase concentration was found to be 100 U of enzyme activity per milliliter of perfusate. Light and electron microscopic evaluation of liver morphology after several steps of the isolation showed distinct morphologic changes in hepatocytes and other liver cells during perfusion. After perfusion with Hanks' calcium- and magnesium-free solution, many hepatocytes exhibited early reversible cell injury. These changes included vesiculation and slight swelling of the endoplasmic reticulum as well as mitochondrial matrix condensation. Subsequent to perfusion with collagenase, the majority of hepatocytes appeared connected to one another only by tight junctional complexes at the bile canaliculi. Multiple evaginations were seen on the outer membrane resembling microville and probably represented the remains of cell-to-cell interdigitations between hepatocytes and sinusoidal lining cells from the space of Disse. The cytoplasmic injury seen after Hanks' perfusion was reversed after collagenase perfusion. After mechanical dispersion, isolated mouse hepatocytes were spherical in shape and existed as individual cells; many (80 to 85%) were binucleated under hase contrast light microscopy. By electron microscopy, cells appeared morphologically similar in cytoplasmic constitution to that seen in intact nonaltered liver cells.

Handwashing to prevent diarrhea in day-care centers

Abstract: Diarrhea has been recognized as a frequent health problem among children enrolled in day-care centers. Thus, we evaluated the effect of a handwashing program in two day-care centers (HWC) on the incidence of diarrhea among children when compared to children in two control centers (CC). After the program was begun, the incidence of diarrhea at the HWC began to fall and after the second month of the study was consistently lower than that at the CC. The incidence of diarrhea in the HWC was approximately half that of the CC for the entire 35-week study period. Adenoviruses, rotavirus, Giardia lamblia, and enteropathogenic Escherichia coli were found in the stools of a small number of ill children, but not pathogen was identified in the stools of most children with diarrhea. These results suggest that a handwashing program will probably prevent at least some of the diarrhea in day-care centers.

Duration of Infection-Derived Immunity to Cholera

Abstract: Four volunteers were rechallenged with Vibrio cholerae (10(6) classical Ogawa 395 organisms) 33-36 months after their initial induced cholera infection; none of the four veterans and four of five control volunteers developed diarrhea (P = 0.04). All control subjects, but only one veteran, had positive coprocultures. Three of the four veterans had significant levels of serum IgG antitoxin before challenge, but none had measurable intestinal levels of secretory IgA antitoxin. Significant rises in levels of serum vibriocidal and antitoxic antibody occurred in all control subjects and in two veterans, who also manifested rises in levels of intestinal secretory IgA antitoxin. The impressive duration of infection-derived immunity suggests that the most promising approach to development of cholera vaccines may be to mimic natural immunity with orally administered, attenuated strains of V. cholerae.

Natural history of adrenal cortical carcinoma: A clinicopathologic study of 42 patients

Abstract: To study the biologic behavior and natural history of this rare but challenging tumor faced by oncologists, a clinicopathologic study of 42 patients with histologically proven adrenal cortical carcinoma from Roswell Park Memorial Institute (1929--1977) was done. These constituted .04% of all cancer cases and 0.2% of all autopsy cases. Age range was 3--74 years with median of 53 years; female to male ratio was 1.5 to 1. Clinical manifestations were: abdominal mass (36%), metastatic disease (30%), hormonal excess (17%) and weakness with lethargy (17%). Nine of ten functioning tumors were seen in female patients. Tumors arose in left adrenal in 26 patients, right adrenal in 12, and in four the site could not be determined because of bilateral presence of cancer. Median duration of symptoms was six months. At diagnosis, 52% had distant metastases, 41% had locally advanced tumor and 7% had tumor confined to adrenal. Sixteen patients underwent "curative" resection. Tumor diameter ranged from 1--30 cm with median of 10 cm. Of 28 patients who received different chemotherapeutic regimens, three (11%) had objective response; four of ten patients had objective response to radiation therapy. Overall median and five-year survival rates were 14 months and 24%. Prolonged survival (P less than .05) was noted in women, patients who had "curative" resection, a disease-free interval of more than 12 months, and tumor size greater than 10 cm diameter. Patients with functional tumors had longer median survival than those with non-functional ones (28 vs. 12), but P value was greater than .05. A second primary cancer was noted in 22.4% of cases, breast and lymphoma being the most common. At autopsy in 31 patients, the most common metastatic sites were retroperitoneal lymph nodes 68%, lung 71%, liver 42%, and bone 26%. To improve survival, an aggressive surgical approach is recommended to extirpate the tumor with involved organs and retroperitoneal lymph nodes. Adrenal carcinoma should be suspected in patients with metastatic cancer with an occult primary.

Effects of Estradiol and Progesterone on Catecholamine Turnover Rates in Discrete Hypothalamic Regions in Ovariectomized Rats

Abstract: Norepinephrine (NE) and dopamine (DA) activities were measured in several discrete brain areas (medial preoptic nucleus, suprachiasmatic nucleus, median eminence, and arcuate nucleus) in ovariectomized (OVX) and OVX steroidtreated rats We wished to determine whether catecholamine (CA) mechanisms are involved in estradiol (E2)-induced LH surges and if amplification of such surges by progesterone (P)affects these CA systems Animals were OVX, and 1 week later (day 0), groups were treated with Silastic capsules containing oilor an E2 solution (150 μg/ml in sesame oil) At 0900 h on day 2, E2-treated animals received Silastic capsules containing oil or P (50 mg/ml in oil) This steroid treatment results in physiologicalserum concentrations of both steroids CA concentrations were determined by radioenzymatic assay in animals killed at 1000 or 1500 h on day 2 and in animals which were sacrificed 2 h after receiving a-methyl paratyrosine (400 mg/kg) at 1000 or 1500 h Serum LH, FSH, PRL, E2, and P concentratio

Catecholamine turnover rates in discrete hypothalamic areas and associated changes in median eminence luteinizing hormone-releasing hormone and serum gonadotropins on proestrus and diestrous day 1.

Abstract: We have correlated catecholamine [CA; i.e. norepinephrine (NE), dopamine (DA), and epinephrine (E)] turnover rates in discrete hypothalamic nuclei and in the median eminence (ME), with concentration changes in ME LHRH and serum LH, FSH, PRL, estradiol, and progesterone levels at various times during proestrus and diestrous day 1 in 4-day cyclic rats. CA concentrations were measured with a radioenzymatic assay at 0, 60, and 120 min after ip injection of 400 mg/kg alpha-methyl-p-tyrosine, and rate constants and turnover rates were calculated. In a separate assay NE, DA, and E were separated by two-dimensional thin layer chromatography, and concentrations and turnover rates of CAs were calculated. The microdissected hypothalamic nuclei examined for NE turnover rates included the medial preoptic nucleus (MPN), suprachiasmatic nucleus (SCN), arcuate nucleus (AN), and ME. DA turnover rates also were measured in the MPN, ME, and AN. ME LHRH and serum hormone concentrations were measured by RIA. Between 0900--1200 h, proestrous serum estradiol was elevated, but other serum hormones were basal, and CA turnover rates in the brain were low. However, ME LHRH concentrations increased significantly between 0900--1200 h on proestrus. Between 1200--1500 h, serum LH, FSH, PRL, and progesterone levels increased and ME LHRH levels declined significantly; during this time interval (1200--1400 h), a significant rise in ME NE and DA turnover rates occurred. Between 1500--1700 h on proestrus, while serum gonadotropins were still rising toward peak concentrations, increased ME NE turnover rates were maintained, but increased NE turnover rates also were evident in MPN, SCN, and AN. During this same time interval (1500--1700 h), a marked decline in ME and AN DA turnover rates occurred, although such rates remained unchanged within the MPN. There were no corresponding changes in MPN E turnover rates at any of the time intervals studied. The increased turnover rates of ME NE coupled with the concomitant decline in ME LHRH levels and the rise in plasma LH and FSH levels suggest that increased NE release may be important in initiating preovulatory LH and FSH surges. These changes in brain neurotransmitters and serum hormones are not the result of a diurnal rhythm, since corresponding changes in CA turnover rates or serum gonadotropins did not occur between 0900--1100 h and 1500--1700 h diestrous day 1.

Steroids in severe head injury: A prospective randomized clinical trial

Abstract: This is a prospective randomized study of the efficacy of steroid therapy in patients with severe head injury. One hundred patients were randomized into two equal groups: the steroid group received 5 mg/kg/day of methylprednisolone, and the nonsteroid group received no drug. The groups were similar in their clinical features. All patients received a standardized therapeutic regimen. The patients were also classified as early responders or nonresponders to the overall treatment protocol without regard to steroid administration, on the basis of change in Glasgow Coma Scale score during the first 3 days of admission. There was no statistically significant difference in the outcome of the steroid and nonsteroid group at 6 months. Of the responders who were on steroids, 74% had good outcomes or were disabled, compared with 56% of the responders who did not receive steroids. In the nonresponder group, the patients on steroids were actually associated with a worse outcome than those who did not receive steroids: 75% of the nonresponders who received steroids were dead or vegetative, compared to 56% of those who were not receiving steroids. The data suggest that: 1) the effect of steroids may be different for different patient groups; 2) in order to identify these patients, a sensitive coma scale is needed; and 3) a rational approach to steroid therapy in head-injured patients may be to start all patients on steroids, but to discontinue their use in patients identified as not benefiting from steroid therapy.

Atypical endocrine tumors of the lung.

Abstract: Seven malignant peripheral lung tumors that were diagnosed using light microscopy as large-cell carcinomas or as epidermoid or adenocarcinomas were studied by light and electron microscopic histochemistry. All tumors contained numerous dense-core granules. The cells were joined by desmosomes and contained well-developed tonofilament bundles. Serotonin was demonstrated in six of seven tumors and argyrophilic granules were demonstrated in five of six tumors tested. Four tumors produced mucus. All tumors extended to the visceral pleura and two invaded the chest wall. The existence of lung tumors that contain serotonin and bear argyrophilic putative endocrine granules, but that do not have a light-microscopic histology characteristic of either carcinoid or oat-cell carcinomas, is confirmed. The presumptive endocrine nature of such tumors usually passes unrecognized because they lack criteria to allow diagnosis by routine methods.

Dielectric properties of animal tissues in vivo at frequencies 10 MHz – 1 GHz

Abstract: An open-ended coaxial line sensor in conjunction with an automatic network analyzer was used to measure in vivo the permittivity of several feline tissues (skeletal and smooth muscle, liver, kidney, spleen, and brain – gray and white matter) at frequencies between 10 MHz and 1 GHz. The estimated uncertainties of measurement were between 1.5% and 5%. The data are in general agreement with previously obtained data in vitro and in vivo. Significant differences in the properties of different types of the same tissue (eg, skeletal and smooth muscle) were observed. Many tissues were found to be non-homogeneous in its permittivity.

Effects of Estradiol and Progesterone on Plasma Gonadotropins, Prolactin, and LHRH in Specific Brain Areas of Ovariectomized Rats

Abstract: We examined the effects of physiological concentrations of estradiol (E2) and progesterone (P) on plasma LU, FSH, and prolactin (PRL) and on LHRH concentrations in several microdissected brain regions in ovariectomized (OVX) rats. One week after ovariectomy (Day 0), rats received Silastic capsules containing only sesame oil or 37.5, 75.0 or 150 � E2/ml of oil s.c. TheE2 capsules produced plasma estrogen concentrations of 7.0, 9.6, or 15.4 pg/mI, respectively, on Day 2 whereas oil-treated controls had 5.4 pg/mI of E2 in plasma. All three E2 -treated groups of rats had LH surges of comparable magnitude during the afternoon of Day 2. Two Silastic capsules of P (50 mg/mI) were implanted at 0900 h on Day 2 into E2 -treated rats. In animals in which E2 levels were 7.0 or 9.6 pg/mI, P only moderately amplified the LH surges. However, when plasma E2 concentrations reached 1 5 pg/mI, P treatment evoked a massive release of LH and advanced the time of release by 1 h. In contrast, the stress of inserting oil capsules into ether-anesthetized E2 -treated rats at 0900 h on Day 2 had no effect on afternoon LH surges in these animals. FSH surges occurred only in rats receiving both E2 and P. PRL surges were induced using the highest concentrations of E2 and were advanced in time by P. When the highest dose of E2 was used, LHRH concentrations in the median eminence (ME) increased prior to and decreased during the E2 P-induced surge. These changes were not paralleled by any changes in the other anterior brain regions we examined (suprachiasmatic preoptic nucleus, suprachiasmatic nucleus, medial preoptic nucleus, anterior hypothalamic nucleus, and retrochiasmatic area). No changes in LHRH concentrations were observed under any other steroid treatment regimen. Higher plasma E2 concentrations induced by the 150 �g/ml E2 capsule were correlated with higher LHRH concentraions in the median eminence concomitant with a parallel trend in some of the anterior brain areas: MPN (P<0.06), SPN (P<0.06), and RCA (P<0.03).

Comparison of Bone Graft Materials: Part II. New Bone Formation With Autografts and Allografts: A Histological Evaluation

Abstract: The purpose of this study was to make a direct histological comparison of new bone formation evoked by decalcified freeze-dried bone allograft, freeze-dried bone allograft, autogenous osseous coagulum, and autogenous bone blend. Defects were surgically created in the calvaria of 35 guinea pigs. The graft materials were placed in porous nylon chambers and implanted into the defects. Implanted empty nylon chambers served as controls. The animals were sacrificed at 3, 7, 14, 21, 28, 35, and 42 days. New bone formation was determined quantitatively from histologic preparations. It was concluded that, in this model system, decalcified freeze-dried bone allograft is a graft material of high osteogenic potential; autogenous osseous coagulum and bone blend of less potential, and freeze-dried bone allograft even less.

Lactobacillus prophylaxis for diarrhea due to enterotoxigenic Escherichia coli.

Abstract: In vitro and animal experiments indicated that lactobacilli might prevent Escherichia coli from colonizing the intestine and may produce substances counteracting enterotoxin. Lactinex, a commercial preparation of dried Lactobacillus acidophilus and L. bulgaricus, is marketed for uncomplicated diarrhea. Preliminary experiments in nonfasting volunteers indicated that lactobacilli in this preparation colonized the small intestine for up to 6 h. To evaluate the protective efficacy of Lactinex, a double-blind randomized study was carried out in which 48 volunteers (23 receiving Lactinex and 25 receiving placebos) were challenged with E. coli strains that produced heat-stable or heat-labile enterotoxins or both. No significant differences between the two groups were noted with respect to attack rate, incubation period, duration of diarrhea, volume and number of liquid stools, and coproculture yields. These data suggest that this lactobacillus preparations does not prevent or alter the course of enterotoxigenic E. coli diarrhea in adults. Lack of efficacy occurred despite efforts to maximize small bowel colonization, including administration of Lactinex in milk and in a 6-hour-interval regimen during 36 h before and 96 h after challenge.

Comparison of Bone Graft Materials: Part I. New Bone Formation With Autografts and Allografts Determined by Strontium-85*

Abstract: The purpose of this study was to obtain a direct comparison of the bone forming abilities of autogenous osseous coagulum, autogenous bone blend, freeze-dried bone allograft, and decalcified freeze-dried bone allograft. Defects were created in the calvaria of 35 guinea pigs. The graft materials were placed in porous nylon chambers and implanted into the defects. Empty nylon chambers served as the controls. Three days prior to sacrifice, each animal received an injection of 85Sr. The animals were killed in groups of five at 3, 7, 14, 21 28, 35, and 42 days. At sacrifice, a small section of ilium was removed from each animal. The samples were recovered, weighed, and the uptake of 85Sr into new bone determined. An osteogenic index was obtained by dividing cpm/mg for each sample by cpm/mg of ilium. It was concluded that in this model system decalcified freeze-dried bone allograft is a graft material of high osteogenic potential while autogenous bone blend and osseous coagulum were of less potential, and freeze-dried bone allograft even less.

P300 and feedback provided by absence of the stimulus.

Abstract: This experiment is concerned with the issue of functional equivalence of emitted (in response to ahsence of a stimulus) and evoked (in response to presentation of a stimulus) P300s. Subjects attempted to estimate a 600-msec time interval hy the method of reproduction. Subjects were informed whether the time interval was under- or overestimated and whether the estimation error magnitude was within a limit (“correct” estimate, positive feedback) or exceeded the limit (“incorrect,” negative feedback). This feedback was presented by means of either a single event or a combination of two events. Each event consisted of a pair of stimuli. Emitted, as well as evoked, early fronto-central and late parietal P3OOs were elicited by the feedback event regardless of whether positive or negative feedback was delivered, and regardless of whether feedback was delivered by a single event or by the combination of two events. In addition, what appears to be a positive Slow Wave was found following the first stimulus ofthe feedback event when this stimulus was low intensity indicating an underestimation. The other condition (high intensity, overestimation) was followed by a CNV. Since these slow wave findings were serendipitous, counterbalancing was not available to determine whether intensity (low vs high) or information (underestimation vs overestimation) was responsible for the difference.

Rapid migration of 111indium-labeled granulocytes to sites of infection.

Abstract: ISOTOPIC labels attached to various blood cells have been used for years to study the course and kinetics of blood components in vivo The use of such labeling in granulocytes to evaluate transfusions or to localize infections has met with uncertain success1 2 3 4 5 6 7 Recently, 111In combined with the chelating agent 8-hydroxyquinoline (oxine) has been used in granulocyte-labeling research8 9 10 The advantages of 111In include tight cytoplasmic binding with minimal in vivo elution and preservation of cell viability and function after the granulocytes are exposed to the isotope11 In addition, the energy spectrum of this element consists of two peaks at 173 and

Toward a Resolution of Methodological Dilemmas in Network Mapping

Abstract: In mapping social networks, investigators have confronted the following choices in the selection of an instrument to assess networks: (1) qualitative versus quantitative approaches; (2) subjective versus objective criteria; (3) synchronic versus diachronic descriptions. Evolving out of fieldwork with discharged mental patients, the Network Analysis Profile was designed to resolve these methodological dilemmas. Although it has not been completely successful in meeting this goal, the Network Analysis Profile offers distinct advantages over other instruments. A description and an illustration of its use are provided.

On the definition of variables in studies of primate dental allometry.

Abstract: Cranial and dental measurements are taken on 253 adult female primates from 32 species. Regression equations are calculated to determine allometric relationships between anterior tooth size, posterior tooth size, and body size. When cranial length or skull length is used as the measure of general size, the results of the equations differ from when body weight is the reference dimension. Similarly, using different definitions of posterior tooth size (such as mandibular second molar length and maxillary postcanine area) alters results substantially. The same occurs with different definitions of anterior tooth size. It has been common in studies of primate dental allometry to generalize from the specific variables measured to broad functional interpretations. However, highly correlated variables cannot be substituted one for another in allometric analyses without important changes in the results of the equation. Interpretation of allometric data is more highly restricted to the precise variables measured in a particular study than has been generally recognized.