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Biomedical subjects

M E Katz

Publications and source records attributed to M E Katz.

At least 37 records · Page 2Linked to original sources
PubMed1995

Lymphoproliferative disease of granular lymphocytes.

We report a case of lymphoproliferative disease of granular lymphocytes that was associated with cutaneous manifestations. Marker studies of skin and blood in this patient revealed that the circulating and infiltrating cells were negative for CD3 and T-cell antigen receptor but were positive for CD16, CD56, and CD57, suggesting natural killer cell origin. The patient had a rapidly progressive course and died within 1 month of presentation.

Aged↗
PubMed1995

Delineation of the virulence-related locus (vrl) of Dichelobacter nodosus.

Dichelobacter nodosus is the primary pathogen implicated in ovine footrot. In this paper we have delineated a 27 kb locus, termed the virulence-related locus (vrl), that was essentially specific for virulent D. nodosus isolates. The precise ends of this locus were mapped and the sequences of the junction regions from the virulent strain A198 were compared to corresponding sequences from the benign isolate C305. The left end of the vrl locus was located in a sequence similar to that of the small stable 10Sa RNA molecule of Escherichia coli, next to a phage-attachment-site-like sequence, which indicated that the vrl locus might have arisen by the integration of a phage. However, no attachment-like sequence could be found at the right end of the vrl locus. In the chromosome of the benign strain the sequences bordering vrl were not contiguous but were separated by about 3 kb. It was concluded that the divergence of the benign and virulent strains at this locus was a multi-step process. Several potential ORFs were identified at the junction regions but only one ORF, encoding a 126 kDa protein, was expressed in a T7 expression system in E. coli.

Amino Acid Sequence↗
PubMed1995

A role for bacteriophages in the evolution and transfer of bacterial virulence determinants.

A virulence-associated region in the genome of Dichelobacter nodosus has been shown to contain an integrase gene which is highly related to the integrases of Shigella flexneri phage Sf6 and coliphages P4 and phi R73, together with open reading frames (vapB, C and D) related to genes borne on plasmids in Neisseria gonorrhoeae, Escherichia coli, Actinobacillus actinomycetemcomitans and Treponema denticola. Similar to P4 and phi R73, the vap region is bracketed by putative bacteriophage att sites and is adjacent to a tRNA gene, which suggests that the vap region has been derived by the integration of a bacteriophage, or a plasmid carrying a bacteriophage-related integrase gene. Many similarities in genes and genes clusters encoding virulence determinants have been found in distantly related bacteria. These genes are often located on plasmids in one organism but on the chromosome in others, implying that transmission of the genes has been followed by integration. Thus, the events which have generated the vap regions of D. nodosus may represent a common mechanism for transfer of virulence determinants. A number of genes involved in the virulence of bacterial pathogens are found on integrated bacteriophages, and we suggest that others will prove to be associated with tRNA genes and/or integrase genes derived from bacteriophages. The use of tRNA genes as integration sites for many bacteriophages and plasmids may favour intergeneric transmission, as tRNA genes are highly conserved.

Attachment Sites, Microbiological↗
PubMed1995

Inflammatory cutaneous metastases from cloacogenic carcinoma of the anus.

BACKGROUND: There are a few tumors that exhibit inflammatory cutaneous metastases. This pattern is particularly difficult to diagnose since it can mimic erysipelas or lymphangitis. OBJECTIVE: This is a presentation of a 69-year-old woman diagnosed with poorly differentiated cloacogenic carcinoma who simultaneously was noted to have an abdominal rash. A biopsy confirmed cutaneous metastasis of her carcinoma. METHODS: Previously published literature on cutaneous metastases were reviewed and summarized. RESULTS: This is the first reported case of an inflammatory cutaneous metastasis arising from cloacogenic carcinoma. CONCLUSION: Cutaneous metastases can present in various forms, including the inflammatory pattern. Because this form mimics other conditions, it is prudent to biopsy any suspicious skin lesion in cancer patients, as it may considerably affect prognosis.

Aged↗
PubMed1995

Mortality rates among 15- to 44-year-old women in Boston: looking beyond reproductive status.

Mortality rates were examined for Boston women, aged 15 to 44, from 1980 to 1989. There were 1234 deaths, with a rate of 787.8/100,000 for the decade. Leading causes were cancer, accidents, heart disease, homicide, suicide, and chronic liver disease. After age adjustment, African-American women in this age group were 2.3 times more likely to die than White women. Deaths at least partly attributable to smoking and alcohol amounted to 29.8% and 31.9%, respectively. Mortality was found to be related more directly to the general well-being of young women than to their reproductive status, and many deaths were preventable. African-American/White disparities were most likely linked to social factors. These findings suggest that health needs of reproductive-age women transcend reproductive health and require comprehensive interventions.

Adolescent↗
PubMed1994

Isolation and characterization of an Aspergillus nidulans gene encoding an alkaline protease.

We have cloned an Aspergillus nidulans gene (prtA) encoding an alkaline protease (Alp) by probing an A. nidulans library with a fragment amplified from an Aspergillus oryzae Alp-encoding gene. The nucleotide (nt) sequence of prtA was determined. The structure of prtA is similar to that of the A. oryzae Alp-encoding gene. The prtA gene is composed of four exons which are separated by three introns of 59, 57 and 54 nt. The deduced amino acid sequence of the prtA product shows a high degree of similarity to proteases from A. oryzae, A. fumigatus and A. flavus. Southern blot analysis suggests that only one copy of this gene is found in the genome of A. nidulans. The extracellular proteases of A. nidulans are regulated by nitrogen, carbon and sulfur metabolite repression. The prtA RNA levels were analysed under different nutrient conditions. No prtA transcript was detected in mycelium grown in medium containing glucose, NH4+ and sulfate. However, prtA transcript levels were high in mycelia transferred to medium lacking a nitrogen, carbon or sulfur source.

Amino Acid Sequence↗
PubMed1994

Genetic organization of the duplicated vap region of the Dichelobacter nodosus genome.

The recombinant plasmid pJIR318 contains a fragment of the Dichelobacter nodosus genome which is associated with virulence. Sequence analysis of the pJIR318 insert has shown that it contains four vap (virulence-associated protein) genes which are homologous to open reading frames found on the Escherichia coli F plasmid and the Neisseria gonorrhoeae cryptic plasmid (M. E. Katz, R. A. Strugnell, and J. I. Rood, Infect. and Immun. 60:4586-4592, 1992). The plasmid pJIR318 hybridizes to three regions of the D. nodosus genome, each of which has now been isolated. Regions 1 and 3 were found to be adjacent in the genome of D. nodosus A198, and the order of the vap genes in vap regions 1 and 2 were shown to be identical. Partial sequence analysis and Southern blot analysis of the vap regions showed that the three regions probably arose by a duplication event(s) followed by insertions and/or deletions. A recombinant plasmid, pJIR749, was isolated from a library of a benign D. nodosus strain, 305. This plasmid contained sequences from both ends of vap region 2. Analysis of pJIR749 showed that the sequences on either side of vap region 2 were separated by 324 bp in the genome of benign strain 305 and that the orientations of the sequences were different. It is clear that a simple insertion or deletion event did not generate the benign and virulent strains studied. A model which describes the evolution of the duplicated vap regions in D. nodosus A198 is presented.

Bacteria, Anaerobic↗
PubMed1994

Transabdominal manually assisted reduction of pediatric intussusception: reappraisal of this historical technique.

PURPOSE: To determine whether manual manipulation of the abdomen during intussusception reduction improves the success rate or affects morbidity. MATERIALS AND METHODS: A retrospective study was performed in 38 cases of intussusception in 35 children over a 33-month period at a pediatric hospital. In all cases, pneumostatic pressure was used as the initial method of treatment. A comparative review of the intussusception literature was also performed. RESULTS: Reduction was achieved with pneumostatic pressure alone in 22 cases (an initial success rate of 58%). Transabdominal manual manipulation was used in 10 cases after initial pneumostatic reduction failed; seven of these 10 cases were treated successfully. These seven additional successes, attributed to manual assistance, significantly improved the success rate from 58% to 76% (P < .016). No perforation or other complication occurred. CONCLUSION: These results and findings of the literature review indicate that transabdominal manual assistance during reduction is a potentially useful technique that has been shunned without scientific basis for longer than 40 years.

Air Pressure↗
PubMed1994

Nephrocalcinosis in very low birth weight neonates: sonographic patterns, histologic characteristics, and clinical risk factors.

Fifty infants weighing less than 1200 grams at birth who survived at least 3 weeks were enrolled in this study, of whom 14 (28%) developed sonographic evidence of nephrocalcinosis by 9 weeks, despite median total furosemide dose of only 2 mg/kg. Risk factors for development of neonatal nephrocalcinosis were white race (P < 0.01) and positive family history of kidney stones (P < 0.001). Sonography demonstrated echogenic foci measuring 2 to 9 mm near the papillary tips in most infants with nephrocalcinosis even though the kidneys apparently had not progressed through the stages of diffuse medullary echogenicity that Patriquin and Robitaille postulated are the sonographic correlates of the Anderson-Carr-Randall progression, a leading theory of renal calculus formation. The presence of intratubular calcifications in the two patients studied post mortem also is contrary to the Anderson-Carr-Randall theories that center on interstitial calcium deposition. Although neonatal nephrocalcinosis shares some clinical risk factors (white race and positive family history of renal calculi) with renal calcium deposition in older children and adults, the prevalent theories of renal calcium deposition do not account for its sonographic or histologic manifestations.

Adult↗
PubMed1993

Variation in hysterectomy rates across small geographic areas of Massachusetts.

OBJECTIVE: Our objective was to determine whether small-area variation in hysterectomy rates exists within Massachusetts and, if so, whether regions with persistently high or low rates can be identified. STUDY DESIGN: By examining data derived from standardized hospital discharge forms between 1982 and 1989, we compared hysterectomy rates among 172 small geographic areas within Massachusetts. The ratios of actual to expected number of hysterectomies for each area were also computed. Statistical significance of rate variation was established by a value of p < 0.01 (chi 3 test). RESULTS: The-hysterectomy rate per 1000 women varies fivefold across small-population areas of Massachusetts. Eight areas had persistently high and five had persistently low rates compared with the statewide average. CONCLUSION: Possible explanations for these rate variations include indigenous population factors, supply of health care resources, income, insurance coverage, methodological problems in data analysis, and variation in professional judgment with regard to the indication for hysterectomy. Only a combination of the study of local causes of high and low rates and the study of the clinical outcomes of different treatment decisions will allow physicians to develop an informed consensus on appropriate indications for surgery.

Female↗
PubMed1993

Nephrocalcinosis in very low birth weight neonates: family history of kidney stones and ethnicity as independent risk factors.

Serial renal ultrasonography was performed in 50 consecutive neonates with birth weights less than 1200 gm who survived to at least 3 weeks of age. Nephrocalcinosis developed in 8 (67%) of 12 white and only 6 (16%) of 38 nonwhite infants (p < 0.01). Seven (78%) of nine infants with a family history of kidney stones had nephrocalcinosis compared with only 7 (17%) of 41 without a family history of kidney stones (p < 0.001). We conclude that nephrocalcinosis in our population of very low birth weight neonates is significantly and independently associated with a family history of kidney stones and white race.

Birth Weight↗
PubMed1992

Intussusception reduction 1991: an international survey of pediatric radiologists.

A detailed survey of intussusception reduction practices at the International Pediatric Radiology '91 meeting in Stockholm yielded 78 responses from radiologists representing 21 countries on six continents. Results indicates a striking lack of conscensus on basic technical issues such as the type of contrast material or reducing agent, the pressure limits for reduction, the use of balloon-tip tubes, the role of sedation, manipulation of the abdomen during reduction, and duration of symptoms beyond which reduction would not be attempted. For example, while gas reduction has been strongly promoted in the literature during the late 1980's, only 34.7% of the respondents indicated that this was their principle choice of reducing agent. Among technique choices which produced significant correlations with outcome, it is noteworthy that pooled data suggest an eightfold increase in perforations among those using gas rather than liquid for reduction. Also, although 53.8% of respondents use parenteral sedation at least part of the time, those who reported using it regularly had significantly lower success rates than all other radiologists. This study provides a current sampling of international opinion in a subject of importance to all pediatric radiologists; and by linking the response with reported outcomes suggests opportunities for further investigation.

Child↗
PubMed1992

Molecular characterization of a genomic region associated with virulence in Dichelobacter nodosus.

The major pathogen implicated in footrot, a highly contagious disease of sheep, is the strict anaerobe Dichelobacter nodosus (formerly Bacteroides nodosus). Sequence analysis of a 2,262-bp segment of the D. nodosus genome which is more prevalent in virulent isolates than in other isolates showed the presence of four open reading frames which appeared to have consensus transcriptional and translational start signals. These virulence-associated genes have been designated vapABCD. Two of the three copies of the vap region in the genome of the reference strain D. nodosus A198 were shown to carry all of the vap genes, whereas one copy contained only the vapD gene. The VapD protein was gel purified, shown to contain the predicted amino-terminal sequence, and used to raise rabbit antibodies. Western blots (immunoblots) showed that all of the D. nodosus strains tested that contained the vap region produced the VapD protein. The VapD protein had significant amino acid sequence identity with open reading frame 5 from the cryptic plasmid of Neisseria gonorrhoeae, and the vapBC operon had sequence similarity with the trbH region of the Escherichia coli F plasmid. It is proposed that these gene regions evolved from the integration of a conjugative plasmid from another bacterial species into the D. nodosus chromosome.

Bacterial Proteins↗
PubMed1992

Molecular characterization of the lam locus and sequences involved in regulation by the AmdR protein of Aspergillus nidulans.

The lam locus of Aspergillus nidulans consists of two divergently transcribed genes, lamA and lamB, involved in the utilization of lactams such as 2-pyrrolidinone. Both genes are under the control of the positive regulatory gene amdR and are subject to carbon and nitrogen metabolite repression. The lamB gene and the region between the two genes have been sequenced, and the start points of transcription have been determined. Within the lam locus are two sequences with homology to elements, required for AmdR regulation, found in the 5' regions of the coregulated genes amdS and gatA. In vitro and in vivo assays were used to investigate the lam and gatA regulatory elements. One of the three gatA elements and one of the two lam elements were shown to bind AmdR protein in vivo and activate transcription. With a gel shift mobility assay, in vitro binding of AmdR protein to the functional gatA element was detected. Both the functional gatA and lam boxes contain within them a CAAT sequence. In vitro binding analysis indicates that a CCAAT-specific factor(s) binds at these sequences, adjacent to or overlapping the AmdR protein-binding site.

Amino Acid Sequence↗
PubMed1991

Identification of three gene regions associated with virulence in Dichelobacter nodosus, the causative agent of ovine footrot.

Dichelobacter nodosus (formerly Bacteroides nodosus) is a Gram-negative strict anaerobe and is the primary pathogen involved in ovine footrot. A comparative hybridization strategy was used to isolate recombinant clones which hybridized to DNA from a virulent strain of D. nodosus but not with a benign isolate. Three virulence-associated gene regions were identified and one of these regions was shown to be present in multiple copies in the D. nodosus genome. Hybridization studies on 101 clinical isolates of D. nodosus showed that these strains could be divided into three hybridization categories which could be correlated with the virulence of the isolates. The recombinant clones have considerable potential for the development of a gene-probe-based method for the differential diagnosis of ovine footrot.

Animals↗