Biomedical subjects
Publications and source records attributed to J Weiss.
We report a case of a metastasizing proliferating trichilemmal cyst. A 78-year-old man had multiple common and two proliferating trichilemmal cysts, one of which showed malignant transformation as evidenced by lymph node metastases. Despite surgical removal of the malignant tumor, extensive metastatic disease rapidly occurred. This case exemplifies the difficulties in diagnosis and treatment of these rare tumors and their unpredictable course.
Extraintestinal strains of Escherichia coli possess a variety of virulence factors that enable them to cause disease. These strains express a group 2 capsular polysaccharide which is important in the pathogenic process. Extraintestinal strains evaluated to date are also capable of producing the group 1 capsular polysaccharide colanic acid. The blood isolate CP9 (O4/K54/H5) constitutively produces the group 2, K54 capsule but can be induced to produce colanic acid. In this report we assess whether colanic acid contributes to the pathogenesis of this extraintestinal pathogen. CP9 and its derivatives that are deficient in their ability to produce colanic acid (TR94), the K54 group 2 capsule +/- colanic acid (CP9.137, TR1374) and the O4 specific antigen +/- colanic acid (CP921,CP925) were used to test whether the group 1 capsule colanic acid conferred protection against the bactericidal effects of serum and recombinant bactericidal/permeability-increasing protein (rBPI-23) in vitro. Additionally, CP9, CP9.137 and TR94 were evaluated in the rat granuloma pouch, an in vivo model for localized infection, and by intraperitoneal inoculation into mice, a systemic infection model. In summary, the inability of CP9 to produce colanic acid in the presence or absence of its K54 and O4 antigens had no effect on its ability to survive these host defenses in vitro and did not affect its virulence in these two in vivo models of infection.
BACKGROUND: Opioids are used by patients who have conditions ranging from the acute pain of surgery and chronic cancer pain to substance abuse. Despite their widespread use and considerable experimental data about them, little is known about how opioids may alter in vivo immunity in humans. This study was designed to evaluate the in vivo effect of morphine on human peripheral blood immune functions. METHODS: Healthy volunteers underwent continuous exposure to morphine for 36 h including a 24-h intravenous infusion in the hospital. Peripheral blood was drawn for immune function studies at five measurement times before, during, and after morphine exposure. Peripheral blood mononuclear cells were tested for acute and gamma-interferon-stimulated natural killer cell cytotoxicity (NKCC), antibody-dependent cell cytotoxicity, antibody Fc receptor expression, and human immunodeficiency virus infectivity. RESULTS: Significant suppression of NKCC was observed at 2 and 24 h after the onset of intravenous morphine exposure. Suppression of NKCC persisted for 24 h after termination of morphine infusion in a "high"-dose study group. gamma-Interferon-stimulated NKCC and antibody-dependent cell cytotoxicity were also decreased after 24 h of intravenous morphine exposure. No effect on Fc receptor expression was observed. Mean virus antigen production after lymphocyte infection with human immunodeficiency virus was not increased (p24 100 ng/ml after morphine vs. 43 ng/ml before morphine; P = 0.17). CONCLUSIONS: These results suggest that morphine administration, at doses within the range of analgesic use, can cause measurable suppression of some components of the human cellular immune system.
In the present study, we investigated the expression of the tumour suppressor protein p53 in 113 primary and 43 metastatic malignant melanomas by immunohistochemistry, and correlated the findings with clinicopathological parameters such as histological melanoma subtype, thickness of primary melanomas (Breslow thickness) and patient outcome. In primary melanomas, the polyclonal anti-p53 antibody CM-1 detected immunoreactivity in 70% of the lesions, predominantly in the cytoplasm. Signals were observed in this cellular compartment in 57% of the melanomas, whereas in 32% nuclear p53 over-expression was detected. Immunohistochemistry, using the monoclonal antibody DO-1, revealed lower staining frequencies. However, both antibodies showed congruent results in approximately 80% of the cases. Overall, immunoreactivity was observed in 73% of superficial spreading melanomas, but only in 52% of lentigo maligna melanomas. This difference (P < 0.001) was mainly due to a lower frequency of cytoplasmic immunoreactivity (P < 0.002). There was no difference with respect to cytoplasmic and nuclear immunoreactivity between thin (< 1 mm thickness) and thicker primary melanomas. Staining frequencies detected in metastatic lesions seemed to be lower than in primary tumours. In 103 primary melanomas, follow-up data for at least 5 years were available. In 71% (54 of 76) of the primary melanomas which did not recur, and in 78% (21 of 27) of tumours with subsequent metastases, p53 over-expression was detected by CM-1. However, this difference was not statistically significant. The results of the present study indicate that immunoreactivity to anti-p53 antibodies is a common observation in malignant melanomas, with staining signals predominantly found in the cytoplasm of cells.(ABSTRACT TRUNCATED AT 250 WORDS)
To what extent the host defense role of granule-associated antibacterial proteins and peptides of PMN includes extracellular action has not been established. To address this question, we have analyzed the antibacterial activity of cell-free (ascitic) fluid (AF) obtained from glycogen-induced sterile inflammatory rabbit peritoneal exudates in which > 95% of the accumulating cells are PMN. AF, but not plasma collected in parallel, exhibits potent activity toward serum-resistant Gram-negative and Gram-positive bacteria. Total and specific antibacterial activity of AF increases during the first 12 h after injection of glycogen in parallel with the influx of PMN. At maximum, > 99% of 10(7) encapsulated Escherichia coli and Staphylococcus aureus are killed in 30 min/ml of AF. Neutralizing antibodies against the bactericidal/permeability-increasing protein (BPI) of PMN abolishes activity of AF toward encapsulated E. coli but has no effect on activity vs staphylococci. However, BPI alone (approximately 1 microgram/ml in AF) can only account for < or = 20% of AF activity toward E. coli. AF also contains 15 kD PMN proteins (p15s) that act in synergy with BPI. Purified BPI and p15s, in amounts present in AF, reconstitute the growth-inhibitory activity of AF toward encapsulated E. coli. These findings show for the first time an extracellular function of endogenous BPI, providing, together with the p15s, a potent microbicidal system toward Gram-negative bacteria resistant to plasma-derived proteins and phagocytes in inflammatory exudates.
PURPOSE: A randomized trial was performed to investigate the ability of the nucleoside transport inhibitor dipyridamole (DP) to enhance the antitumor activity of fluorouracil (5-FU)/leucovorin (folinic acid [FA]). PATIENTS AND METHODS: One hundred eighty-one untreated patients with advanced colorectal cancer were randomized to receive 5-FU 600 mg/m2 plus FA 300 mg/m2 on days 2 to 4 with or without DP 75 mg orally three times daily on days 1 to 5. Cycles were repeated every 3 weeks. Only patients with documented tumor progression before therapy were eligible. 5-FU pharmacokinetics using high-performance liquid chromatography (HPLC) were assessed in 11 nonrandomized patients receiving paired cycles with or without DP. RESULTS: One hundred seventy-four patients were assessable for toxicity and response. There was no significant difference in toxicity, except DP-related headache in 24% of patients. An objective response rate of 15% (one complete response [CR] and 13 partial responses [PRs]) for 5-FU/FA and 13% (two CRs and nine PRs) for 5-FU/FA/DP was observed. The dose-intensity of 5-FU delivered was significantly higher (1.09- to 1.16-fold) for the DP-containing arm. Pharmacokinetic parameters of 5-FU did not differ significantly, except for a prolonged half-life (t1/2) induced by DP. The median time to progression (P = .8) and the median survival time (11.6 months for 5-FU/FA v 9.3 months for 5-FU/FA/DP; P = .14, log-rank test) were not different between treatment arms. CONCLUSION: Orally administered DP did not improve the antineoplastic activity of 5-FU/FA in patients with advanced colorectal cancer when used at this dose and schedule. The observed increase in 5-FU dose-intensity for FU/FA/DP was not clinically relevant.
A pulsatile GnRH signal is required for the maintenance of LH and FSH secretion. Studies in animals and in perifused pituitary cells have shown that continuous exposure to GnRH leads to decreased gonadotropin secretion and a blunted secretory response to subsequent pulses of GnRH, a process referred to as homologous desensitization. In the current study, we demonstrate that the duration of continuous GnRH exposure required to desensitize the gonadotrope in vitro is less than the durations of most in vivo GnRH pulses. Perifused male rat pituitary cells were tested with 20-sec pulses of 100 nM GnRH at 5-min intervals before, immediately upon termination of, and after GnRH infusions of varying concentration and duration. Desensitization in response to a GnRH infusion was calculated as the decrease in the LH response to the pulse of GnRH immediately after the infusion (Dsn pulse) compared to the mean LH response to GnRH pulses before and after the infusion. Gonadotropes were completely desensitized after a 2-min infusion of 10 nM GnRH (P < 0.05), the shortest duration tested. Endogenous GnRH pulses, by contrast, average more than 5 min in length. When the duration of GnRH infusion was held constant at 4 min, a concentration response for GnRH-induced desensitization was observed. Gonadotropes were desensitized by GnRH concentrations as low as 1 nM (P < 0.05), and maximal desensitization was observed with 5 nM GnRH. To determine the recovery period for GnRH-induced desensitization, a second series of experiments was performed. Experiments were conducted as described above, except the cells were perifused with medium that did not contain GnRH (recovery) for varying periods between the GnRH infusion and the Dsn pulse. A small response (16% of control) to the Dsn pulse of GnRH was observed after 1 min of recovery, and the response was not different from the control value (P > 0.05) after a 3-min recovery period. This recovery period is consistent with the ability to respond to endogenous GnRH pulses, which rarely exceed two per h. We conclude that GnRH-induced secretory desensitization and recovery occur within endogenous GnRH pulse durations and interpulse intervals, respectively. These data raise the possibility that homologous desensitization occurs under some in vivo conditions, providing an unexpected mechanism for physiological regulation of gonadotropin secretion.
Pituitary GnRH receptor (GnRH-R) messenger RNA (mRNA) levels are regulated dynamically during the rat estrous cycle. GnRH-R mRNA levels increase 3-fold on the morning of proestrus and remain elevated throughout the gonadotropin surges, after which they decline rapidly. Because the day of proestrus is characterized by complex changes in the steroidal milieu and increased release of hypothalamic peptides such as GnRH, a series of in vivo steroid replacement and in vitro perifusion studies was used to assess the relative contributions of estrogen (E), progesterone (P), and GnRH to the induction and decline of GnRH-R gene expression during the gonadotropin surges. Steroid replacement studies in ovariectomized (OVX) E-primed rats demonstrated that GnRH-R mRNA levels were elevated before and during the E-induced LH surge (1000-1800 h). Receptor mRNA levels declined after the peak of the LH surge and were significantly lower by 2000 h. Pentobarbital treatment, which inhibits hypothalamic input and the LH surge, prevented the gonadotropin surge-associated increase in GnRH-R mRNA levels in E-primed OVX rats. Although GnRH-R mRNA levels did not change throughout the day of experiments in OVX unprimed rats, treatment with pentobarbital significantly reduced GnRH-R mRNA expression in these animals. P treatment of E-primed OVX rats had no significant effect on GnRH-R mRNA expression during the LH surge, but significantly reduced mRNA levels immediately after the LH surge (2000 h). Data from in vitro perifusion experiments using either metestrous or proestrous pituitary glands demonstrated that pulsatile GnRH up-regulates the expression of its own receptor mRNA at both estrous cycle stages. Based on these results, we conclude that enhanced GnRH-R mRNA expression observed on the day of proestrus is largely due to the actions of E, exerted indirectly via hypothalamic routes (presumably through enhanced GnRH secretion). Furthermore, preovulatory P secretion may account for the rapid decline in GnRH-R mRNA levels observed on the evening of proestrus.
Activin markedly stimulates FSH beta messenger RNA (mRNA) levels in rat pituitary cells. Nonetheless, the molecular mechanisms through which activin enhances FSH beta gene expression are not clear. To assess the role of transcriptional activation in activin stimulation, we first transfected two -2300FSH beta Luc constructs into primary pituitary cells and treated them with activin in plated culture and perifusion. Basal expression of the constructs was low, and no activin response was observed. These results suggested that additional FSH beta sequences are required for basal expression or that the effects of activin are not transcriptional. An alternative approach for measuring transcriptional responses was developed based upon changes in the levels of FSH beta primary transcripts (FSH beta-PT; newly transcribed mRNAs that still contain the first intron) after activin (3 ng/ml) stimulation of perifused rat pituitary cells. An increase in FSH beta-PT was observed after 30 min of activin stimulation, preceding the first observable rise in mature FSH beta mRNA. Levels of FSH beta-PT peaked between 1-2 h, then fell to a lower level (28% of maximal) at 4 h, which was maintained through 10 h of activin stimulation (36% of maximal at 10 h). Mature FSH beta mRNA levels peaked between 2-4 h, which is after the increase in FSH beta-PT, and fell more gradually between 4-10 h of stimulation (56% of maximal at 10 h). Unstimulated levels of mature mRNA and FSH beta-PT did not vary significantly over the course of the experiments. Cotreatment with the transcriptional inhibitor actinomycin-D (2 microM) blocked activin stimulation of both FSH beta-PT and FSH beta mRNA, confirming the transcriptional basis for these events. In summary, we have documented rapid and sequential increases in FSH beta-PT and mature FSH beta mRNAs after activin stimulation, which are prevented by transcriptional blockade. These data provide evidence that the increase in FSH beta mRNA levels after activin treatment are at least partly due to transcriptional activation of the FSH beta gene.
The bactericidal/permeability-increasing protein (BPI), a potent cytotoxin specific for Gram-negative bacteria and an endotoxin-neutralizing agent, is a major component of the antimicrobial arsenal of mammalian polymorphonuclear leukocytes. The antibacterial and endotoxin-neutralizing activities of the N-terminal portion (approximately 25 kDa) of BPI are at least equal to those of the holoprotein (approximately 50 kDa). Recombinant N-terminal fragments of BPI are antibacterial and inhibit host cell responses to endotoxin in whole blood ex vivo and in animal experiments. BPI administered to both animals and man is apparently nontoxic and nonimmunogenic and acts synergistically with some antibiotics. Thus, the prospects for the therapeutic use of bioactive BPI fragments in serious Gram-negative bacterial infections are highly encouraging.
In his 1941 article, "The Facts of Observation in Psychoanalysis," Siegfried Bernfeld wrote that observing the sequence of events leading up to and following the patient's confessing a secret is important for psychoanalytic theory. The patient's confessing a secret is important for psychoanalytic theory. The patient's confessing a secret may follow a comment by the analyst that clears away the obstacles to the patient's confessing by creating an encouraging atmosphere and reducing the patient's shame or distrust. Bernfeld believed that the study of this sequence would be fruitful for the development of psychoanalysis. His article now seems prescient. Members of the San Francisco Psychotherapy Research Group have used formal empirical methods to study Bernfeld's thesis, and we have found strong support for his assumptions.
The usability of the haematology analyzers ¿F-800¿ and ¿System 9000+¿ was investigated in cats using 40 blood samples. Reference measurements were done with a haemocytometer or the microhaematocrit method. Reliable leukocyte counts were measured with the analyzer F-800 in cases only, when the histogram rendered possible a clear demarcation of the leukocyte curve (r=0.97, n=25). With the analyzer System 9000+ a changed basic adjustment of the inferior discriminator (49 fl) vouched for a close correlation with the values measured visually (r=0.94). The volume distribution curves of the erythrocytes and thrombocytes which were partly overlapping allowed an approximate counting of the thrombocytes with both analyzers only of one half of the samples. The inaccuracy resulting from the inexact separation had only a relatively unimportant effect on the automatically measured erythrocyte count due to the numerical relation of erythro- and thrombocytes. Here at a close correlation to the haemocytometer method (r=0.95) was found as well as slightly higher values with the automatic counting. The haematocrit measured with the analyzer F-800 and to a smaller extent by the use of the System 9000+ lay distinctly higher in relation to the values measured by microhaematocrit, when the analyzers were calibrated with human standards. Besides a species specific calibration of the haematocrit and a particular basic adjustment for leukocyte counting with the analyzer System 9000+, the use of the investigated haematology analyzers on feline blood requires an individual estimation of the histograms and removing of the discriminators as well as frequently a repetition of the leukocyte- and thrombocyte counting with a haemocytometer.
Extracellular 14-kDa phospholipases A2 (PLA2) in inflammatory exudates can contribute to bacterial phospholipid (PL) degradation during phagocytosis of Escherichia coli by polymorphonuclear leukocytes (PMN) and are highly active toward E. coli treated with the bactericidal/permeability-increasing protein (BPI) purified from PMN. PLA2 activity toward BPI-treated E. coli varies greatly among members of this conserved family of enzymes and apparently depends on a cluster of basic residues in a variable surface region near the NH2 terminus for recognition of this biological target (Weiss, J., Wright, G.W., Bekkers, A.C.A.P.A., van den Bergh, C.J., and Verheij, H.M. (1991) J. Biol. Chem. 266, 4162-4167). We have examined by site-specific mutagenesis of a recombinant PLA2 that is identical to an enzyme in human synovial fluid (containing His-6, Arg-7, Lys-10, and Lys-15 and a global net charge of +15) the role of basic residues in this region in PLA2 action against PLA-deficient (pldA-) E. coli. Substitution of Ser for Arg-7 +/- Gln for Lys-15 caused, respectively, about a 10- and 25-fold reduction in BPI-dependent PLA2 binding and activity to E. coli, but had no effect on hydrolysis of PL of autoclaved E. coli or dispersions of purified PL. PL degradation during phagocytosis was increased after pretreatment of E. coli (or PMN) with wild-type PLA2 followed by removal of unbound PLA2. Thus, the PLA2 binds to cells before phagocytosis followed by internalization of the enzyme along with E. coli and intracellular action. Mutant (e.g. R7S +/- K15Q) PLA2 show the same BPI-independent binding to E. coli as the wild-type enzyme but 10-30-fold reduced activity during phagocytosis, reflecting lower intracellular activity of these enzymes. Thus, structural determinants first implicated in PLA2 action toward E. coli treated with purified BPI apparently are also important in the intracellular action of PLA2 during phagocytosis by PMN.
It has been suggested (Kini, R. R., and Evans, H. J. (1987) J. Biol. Chem. 262, 14402-14407) that the anticoagulant activity of members of the 14-kDa phospholipase A2 (PLA2) family depends on the presence of basic residues within a variable surface region (residues 54-77) distinct from both the conserved catalytic machinery and surface sites mediating the antibacterial action of these enzymes (see Weiss, J., Inada, M., Elsbach, P., and Crowl, R. M. (1994) J. Biol. Chem. 269, 26331-26337). To further define the determinants of the anticoagulant activity of PLA2, we have analyzed the inhibitory effects of purified native and recombinant PLA2 on cell-free prothrombinase. Both native and recombinant wild-type pig pancreas (net charge -1) and human "secretory" PLA2 (net charge +15) produced similar dose-dependent inhibition of prothrombinase activity that was significantly less potent than a toxic PLA2 purified from snake venom. Site-specific mutations that either increased or decreased PLA2 activity toward bactericidal/permeability-increasing protein-treated Escherichia coli by up to 50-fold had no effect on antiprothrombinase activity. In contrast, substitution of Arg for Asp-59/Gly for Ser-60 in the pig PLA2 increased antiprothrombinase activity by 5-10-fold without affecting catalytic activity toward a range of phospholipid substrates or antibacterial activity. Comparison of antiprothrombinase activity of catalytically active and inactive forms of the PLA2 and under a range of phospholipid conditions revealed that the potent antiprothrombinase activity of native toxic venom PLA2 and of the D59R.S60G mutant pancreatic PLA2 reflect combined catalytic and noncatalytic actions, the latter apparently dependent on basic residues at discrete surface sites in the enzyme.
Karyotypic and molecular data indicate that genetic events involving the chromosome region 10q22-10qter may be related to tumorigenesis in malignant melanoma. To test this we analyzed 10 polymorphic microsatellite repeats in the region 10q22-qter, using a polymerase chain reaction-based assay for loss of heterozygosity and DNA isolated from normal and tumor tissue from 26 individuals with malignant melanoma. The samples included 19 paired normal and malignant tissues representing various stages of melanoma as well as 7 cases in which samples from at least 2 different points in time during tumor progression were available. Our findings indicate that loss of heterozygosity of 10q22-10qter is a frequent event, that the observed loss of heterozygosity does not result from whole chromosome loss, and that it is associated with tumor progression. Finally, the appearance of new alleles in two of the tumors may indicate the involvement of DNA replication errors in melanoma analogous to such events in other tumor types.
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Epidural and subarachnoid opioids have been associated with the development of oral herpes simplex lesions. Because of this risk, some anesthesiologists avoid neuraxial morphine in parturients with a history of herpes simplex virus labialis. When we began using neuraxial opioids for analgesia after cesarean delivery, we did not see any increased incidence of facial lesions. To confirm this impression, we studied 357 consecutive parturients presenting for elective or emergent cesarean delivery between 1 December 1989 and 27 June 1990. The women received spinal, epidural, or general anesthesia. Two hundred and one women received either spinal or epidural morphine, the remaining 156 parturients received only systemic opioids for postoperative analgesia. An investigator saw each patient daily until discharge. Only 11 patients (3%) developed oral lesions while hospitalized. None of these women had severe lesions. Neuraxial morphine did not increase the risk of labial lesions significantly (3.5% vs. 2.6%). Despite published data to the contrary, we found no correlation between neuraxial morphine and the risk of facial herpes virus lesions in women after cesarean delivery. We offer patients the option of neuraxial morphine for analgesia after cesarean delivery despite any history of oral herpes lesions.