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Biomedical subjects

M H Klein

Publications and source records attributed to M H Klein.

At least 19 recordsLinked to original sources
PubMed1992

Synergistic induction of promoters containing metal- and glucocorticoid-responsive elements.

We have shown that it is possible to synergistically activate gene transcription when several glucocorticoid responsive elements (GREs) and metal responsive elements (MREs) that coexist within the same promoter are induced simultaneously. To demonstrate this, additional GREs were introduced into a human metallothionein IIA (hMT-IIA) promoter in which some constitutive elements had been deleted. The transcriptional strength and inducibility of the modified hMT-IIA promoters were studied in transient expression experiments using the CAT gene as a reporter. As a result of synergistic activation of transcription by CdCl2 and dexamethasone, the induced expression levels of the modified promoters were significantly higher than those obtained with wild-type hMT-IIA. Since the increase in inducible expression was not accompanied by a concominant increase in basal levels, the inducibility of the modified MT promoters was up to 6-fold higher. The degree of transcriptional synergism was shown to depend on the position and the number of GREs introduced. Thus, the engineering of synthetic promoters that include both GREs and MREs should offer the opportunity to develop a new series of improved inducible mammalian expression vectors.

Animals↗
PubMed1992

Osteoid osteoma: radiologic and pathologic correlation.

Sixty-seven cases of osteoid osteoma were studied at the Hospital for Joint Diseases between 1980 and 1989. The lesions were categorized according to location: medullary, cortical, or subperiosteal and were further grouped as intracapsular and extracapsular. The histologic features of trabecular thickness, reactive bone formation, proportion of fibrovascular stroma, and ratio of osteoid and mineralized matrix were examined. The radiographic features were compared. The literature is reviewed. We include our experience with tetracycline labelling.

Adolescent↗
PubMed1992

A comparison of two computer-administered versions of the NIMH Diagnostic Interview Schedule.

This study compared three versions of the NIMH Diagnostic Interview Schedule (DIS): "traditional" interviewer-administered DIS; computer-administered DIS (subject interacting alone with computer); computer-prompted DIS (interviewer using computer program as a guide). Kappas for 20 diagnoses ranged from .15 to .94, and averages for the three method pairs ranged from .57 to .64, which are comparable to other DIS reliability studies. Agreement between pairs of methods were comparable. Subjects' attitudes toward the computer interview were positive. While they felt they could better describe their feelings and ideas to a human, they found the computer contact less embarrassing. Overall, subjects had no preference for one method over another. Measures of social desirability and deviant response biases were correlated with diagnostic results. Reading ability did not affect subject's ability to respond to the DIS, although subjects with lower reading levels preferred the computer interview more.

Adult↗
PubMed1992

Comorbidity of personality disorders and depression: implications for treatment.

This article reviews naturalistic and controlled studies of the impact of comorbidity of personality disorders and depression on response to various forms of treatment. The findings support the common belief that personality disorders are associated with a poorer response to treatment for depression. In contrast, the limited data available suggest that the presence of depression may be a positive prognostic indicator for patients with borderline and antisocial personality disorder. There are insufficient data to draw conclusions regarding the influence of specific types of personality disorders on outcome with specific forms of treatment for depression. More specific assessment of personality disorders, particularly of possible underlying dimensions, is likely to be a more fruitful approach than the currently used categorical approach in identifying effective treatments for patients with personality disorders and depression.

Antidepressive Agents↗
PubMed1992

Construction of Bordetella pertussis strains that overproduce genetically inactivated pertussis toxin.

Nontoxic analogs of pertussis toxin (PT), produced by in vitro mutagenesis of the tox operon, are immunogenic and protective against infection by Bordetella pertussis. The moderate levels of PT production by B. pertussis, however, make it the limiting antigen in the formulation of multicomponent, acellular, recombinant whooping cough vaccines. To increase production of the highly detoxified Lys9Gly129 PT analog by B. pertussis, additional copies of the mutated tox operon were integrated into the bacterial chromosome at the tox or fha locus by unmarked allelic exchange. Recombinant strains produced in this way secreted elevated levels of the PT analog proportional to gene dosage. The strains were stable during 10-liter fermentations, and yields of up to 80 mg of PT analog per liter were obtained under production-scale conditions. The nontoxic analog was purified and shown to be indistinguishable from material obtained from a B. pertussis strain that contained only a single copy of the toxLys9Gly129 operon. Such strains are therefore suitable for large-scale, industrial production of an acellular whooping cough vaccine containing a genetically detoxified PT analog.

Alleles↗
PubMed1992

Identification of two iron-repressed periplasmic proteins in Haemophilus influenzae.

Protein expression by Haemophilus influenzae under iron-limiting growth conditions was examined. The five type b strains and four nontypeable strains studied all expressed a new protein of about 40 kDa when deprived of iron during growth. Most strains also expressed a protein of about 31 kDa under the same growth conditions. Both the 40- and 31-kDa proteins were not expressed by cells grown in iron-replete medium. The 40- and 31-kDa proteins were not expressed in iron-deficient medium to which an excess of ferric nitrate had been added, and therefore it was concluded that their expression was iron regulated. These iron-repressed proteins were localized to the periplasmic space. The amino-terminal sequences of both proteins were determined. The N-terminal sequence of the 40-kDa protein had 81% similarity to the N terminus of Fbp, the major iron-binding protein of Neisseria gonorrhoeae and N. meningitidis. The 31-kDa protein sequence showed no homology with any known protein sequence. As no plasmids were found in the strains, it was concluded that these proteins were chromosomally encoded.

Amino Acid Sequence↗
PubMed1992

Expression and characterization of genetically engineered human immunodeficiency virus-like particles containing modified envelope glycoproteins: implications for development of a cross-protective AIDS vaccine.

Noninfectious human immunodeficiency virus type 1 (HIV-1) viruslike particles containing chimeric envelope glycoproteins were expressed in mammalian cells by using inducible promoters. We engineered four expression vectors in which a synthetic oligomer encoding gp120 residues 306 to 328 (amino acids YNKRKRIHIGP GRAFYTTKNIIG) from the V3 loop of the MN viral isolate was inserted at various positions within the endogenous HIV-1LAI env gene. Expression studies revealed that insertion of the heterologous V3(MN) loop segment at two different locations within the conserved region 2 (C2) of gp120, either 173 or 242 residues away from the N terminus of the mature subunit, resulted in the secretion of fully assembled HIV-like particles containing chimeric LAI/MN envelope glycoproteins. Both V3 loop epitopes were recognized by loop-specific neutralizing antibodies. However, insertion of the V3(MN) loop segment into other regions of gp120 led to the production of envelope-deficient viruslike particles. Immunization with HIV-like particles containing chimeric envelope proteins induced specific antibody responses against both the autologous and heterologous V3 loop epitopes, including cross-neutralizing antibodies against the HIV-1LAI and HIV-1MN isolates. This study, therefore, demonstrates the feasibility of genetically engineering optimized HIV-like particles capable of eliciting cross-neutralizing antibodies.

AIDS Vaccines↗
PubMed1991

Identification of the Fc gamma receptor class I binding site in human IgG through the use of recombinant IgG1/IgG2 hybrid and point-mutated antibodies.

To characterize the region on human IgG1 responsible for its high-affinity interaction with the human Fc gamma receptor class I (Fc gamma RI), we have analyzed the binding properties of a series of genetically engineered chimeric antidinitrophenyl antibodies with identical murine antibody combining sites and hybrid IgG1/IgG2 human constant (C) regions. In addition, we have investigated a panel of reciprocally point-mutated IgG1 and IgG2 chimeric antibodies to identify the amino acid residues that confer cytophilic properties to human IgG1. Our data unambiguously indicate that cytophilic activity of IgG1 is an intrinsic property of its heavy-chain C region 2 (CH2) domain. We report that the entire sequence spanning residues 234-237 (LLGG) is required to restore full binding activity to IgG2 and IgG4 and that individual amino acid substitutions failed to render IgG2 active. Nevertheless, the reciprocal single point mutations in IgG1 either significantly lowered its activity or abolished it completely. Finally, we observed that an IgG2 antibody containing the entire ELLGGP sequence (residues 233-238) was more active than wild-type IgG1. This finding suggests that in addition to the primary contact site identified in the N terminus of the gamma 1 CH2 domain, secondary sites involving residues from the C-terminal half of the domain may also contribute to the IgG1-Fc gamma RI interaction.

Amino Acid Sequence↗
PubMed1991

Performance of two forms of a computer psychiatric screening interview: version I of the DISSI.

This study reports on the performance of two forms of version I of the Diagnostic Interview Schedule (DIS) computer screening interview, using the traditional interviewer-administered DIS (T-DIS) as the standard. The screening interview was either self-administered (called the S-DISSI) with the subject keying in responses, or interviewer-administered (I-DISSI), with the interviewer keying in the subject's responses. Sensitivity and specificity for both forms were ample (excluding antisocial personality), ranging from 60% to 100% for sensitivity and 54% to 95% for specificity. Concordances with the T-DIS were similar for both forms of the screening interview, ranging from .10 to .87 and compared favorably to those reported by other investigators. The I-DISSI took on average 30 min less than either the T-DIS and S-DISSI. Since the performances of both versions were equivalent, the decision to use either may be based on available resources and characteristics of the study population.

Adult↗
PubMed1991

Strategy for developing a genetically-engineered whole-virus vaccine against HIV.

The production of genetically-engineered, noninfectious virions of human immunodeficiency virus (HIV) represents a novel approach to the development of a safe and effective vaccine for the acquired immune deficiency syndromes (AIDS). Insofar as preparations of inactivated simian immunodeficiency virus (SIV) are now demonstrating protection in immunization-challenge studies in rhesus monkeys, a safe preparation of noninfectious HIV virions produced in a genetically-engineered cell line becomes a logical candidate vaccine for studies in humans. These particles, or pseudovirions, offer distinct advantages over the use of inactivated HIV for human AIDS vaccines. Guarantees of safety without the requirement for inactivation and their potential for structural modification for the modulation of immunogenicity are compelling reasons for the acceptance of HIV pseudovirions as a candidate vaccine in humans.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Production of immunogenic HIV-1 viruslike particles in stably engineered monkey cell lines.

A proviral fragment from human immunodeficiency virus type 1 (HIV-1) (LAV-1BRU) containing only protein-coding information, was expressed in COS cells using constitutive promoters in transient and stable transfection experiments. The presence of viruslike particles in cell supernatants was verified by Western blot analysis, density gradient centrifugation, and electron microscopy. Transfection of Vero cells with a similar construct employing the human metallothionein promoter led to the isolation of stable cell lines exhibiting inducible viruslike particle expression in response to cadmium chloride treatment. Induction ratios for viruslike particle expression were in excess of 1000-fold with production levels of p24 core antigen as high as 0.6 mg/L per 24 h. HIV-1 viruslike particles were immunogenic in mice, leading to strong envelope and core-specific humoral responses after two immunizations. The development of stable cell lines expressing significant quantities of HIV-1 viruslike particles offers an alternative to the use of live virus vectors for the production and evaluation of particle-based AIDS vaccines.

Animals↗
PubMed1990

Gene replacement in Bordetella pertussis by transformation with linear DNA.

We replaced the wild-type TOX operon of Bordetella pertussis with in vitro mutated, detoxified alleles by electroporetic transformation using unmarked linear DNA. Uptake of DNA was selected by transient ampicillin resistance and two simultaneous recombination events resulted in gene-replacement at the natural locus with no integration of heterologous DNA. TOX alleles were stable without selection and recombinant strains secreted non-toxic, fully assembled, protective pertussis toxin (PT) analogues with kinetics similar to the parental vaccine strain under production-scale fermentation conditions. Strains generated in this way are suitable for the production of recombinant whole-cell or component whooping cough vaccines that require no chemical modification of PT.

Alleles↗
PubMed1990

Computer-administered cognitive-behavioral therapy for depression.

The authors evaluated a six-session interactive computer cognitive-behavioral treatment program given to volunteer patients who met Research Diagnostic Criteria (RDC) for major or minor depressive disorder. Patients were randomly assigned to computer-administered cognitive-behavioral treatment, to therapist-administered cognitive-behavioral treatment, or to a waiting-list control condition. After treatment and at 2-month follow-up, both treatment groups had improved significantly more than control subjects in their scores on the Beck Depression Inventory, SCL-90-R depression and global scales, Hamilton Rating Scale for Depression, and Automatic Thoughts Questionnaire. The treatment groups did not differ from each other at either time.

Adult↗
PubMed1990

Nonossifying fibroma of bone: a case report.

An atypical case of nonossifying fibroma involving the femoral neck of a 7-year-old white male is presented. The radiographic characteristics of the lesion were consistent with this diagnosis, although the location is rare. The differential diagnosis included fibrous dysplasia, unicameral bone cyst, chondroblastoma, and eosinophilic granuloma. A final diagnosis was obtained through tissue biopsy and histopathologic review.

Child↗
PubMed1990

Respective contribution of intracellular calcium release and extracellular calcium influx for interleukin-2 synthesis in activated T-cell hybrids.

Triggering of the T-cell receptor (TcR)alpha beta/CD3 receptor complex with anti-allotypic antibodies or concanavalin A (Con A) induced a rapid release of intracellular calcium in a murine T-cell hybridoma model system. Internal calcium release preceded the influx of extracellular calcium, as judged by comparative analysis of time-dependent changes in Quin 2 fluorescence following T-cell activation in the presence and absence of extracellular calcium. The magnitude of intracellular calcium release and extracellular calcium influx depended on the degree of receptor-occupancy and cross-linking. Correlations between the concentration of stimulating ligand, cytosolic calcium increase and IL-2 synthesis indicated a positive but non-linear relationship. Our data suggest that TcR cross-linking may provide a third T-cell activation signal which, in conjunction with protein kinase C activation and cytosolic calcium elevation, together form a signal triad responsible for interleukin-2 (IL-2) synthesis.

Animals↗
PubMed1989

The role of aluminum in the pathogenesis of anemia in an outpatient hemodialysis population.

Anemia is a well-defined complication of aluminum overload in chronic dialysis patients which may be present before other manifestations of aluminum toxicity are obvious. Causes of anemia in chronic renal failure are multiple, and at the present time there is no marker for aluminum-induced anemia. Deferoxamine (DFO) treatment can correct aluminum-related anemia and microcytosis, but may be associated with side effects. Because of the possible role of aluminum in red blood cells in causing the anemia associated with aluminum overload, we attempted to test red blood cell (RBC) aluminum as a marker for aluminum-associated anemia and to assess the prevalence of aluminum-associated anemia in an outpatient dialysis population. Both random plasma aluminum and RBC aluminum correlated well with the increase in plasma aluminum seen following DFO challenge. However, RBC aluminum was affected less by changes in oral aluminum intake than plasma aluminum. There were strong correlations of RBC and plasma aluminum to corpuscular volume (MCV) in our patients. Moreover, patients within the highest quartile of RBC aluminum had a lower mean MCV (82.1 +/- 1.7 vs 89.6 +/- 1.7, p less than .01) and hematocrit (HCT) (24.3 +/- 4 vs 28.2 +/- 1.5, p less than .05) than those within the lowest quartile. These data suggest that aluminum toxicity is an important cause of microcytic anemia in outpatient hemodialysis patients. Prospective long-term studies are needed to further define the usefulness of RBC aluminum in diagnosing and following hemodialysis patients with aluminum-induced anemia.

Aluminum↗