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Biomedical subjects

N Katz

Publications and source records attributed to N Katz.

At least 109 records · Page 6Linked to original sources

The relationship of postoperative delirium with psychoactive medications.

OBJECTIVE: To examine the role of medications with known psychoactive properties in the development of postoperative delirium. DESIGN: Nested case-control study within a prospective cohort study. SETTING: General surgery, orthopedic surgery, and gynecology services at Brigham and Women's Hospital, Boston, Mass. PATIENTS: Cases (n = 91) were patients enrolled in a prospective cohort study who developed delirium during postoperative days 2 through 5. One or two controls (n = 154) were matched to each case by the calculated preoperative risk for delirium using a predictive model developed and validated in the prospective cohort study. MAIN OUTCOME MEASURES: Medication exposures were ascertained from the medical record by a reviewer blinded to the study hypothesis. Exposures to narcotics, benzodiazepines, and anticholinergics were recorded for the 24-hour period before delirium developed in the 91 cases and for the same 24-hour postoperative period for the 154 matched controls. RESULTS: Delirium was significantly associated with postoperative exposure to meperidine (odds ratio [OR], 2.7; 95% confidence interval [CI], 1.3 to 5.5) and to benzodiazepines (OR, 3.0; 95% CI, 1.3 to 6.8). Meperidine had similar associations with delirium whether administered via epidural or patient-controlled routes, although only the epidural route reached significance (OR, 2.4; 95% CI, 1.3 to 4.4; OR, 2.1; 95% CI, 0.4 to 10.7, respectively). For benzodiazepines, long-acting agents had a trend toward stronger association with delirium than did short-acting agents (OR, 5.4; 95% CI, 1.0 to 29.2; vs 2.6; 1.1 to 6.5), and high-dose exposures had a trend toward slightly stronger association than low-dose exposures (OR, 3.3; 95% CI, 1.0 to 11.0; vs 2.6; 0.8 to 9.1). Neither narcotics (OR, 1.4; 95% CI, 0.5 to 4.3) nor anticholinergic drugs (OR, 1.5; 95% CI, 0.6 to 3.4) were significantly associated with delirium as a class, although statistical power was limited because of the high use of narcotics and the low use of anticholinergics in the study population. CONCLUSIONS: Clinicians caring for patients at risk for delirium should carefully evaluate the need for meperidine and benzodiazepines in the postoperative period and consider alternative therapies whenever possible.

Aged↗

Immunoreactivity of a cytokeratin-related polypeptide from adult Schistosoma mansoni.

A saline extract (SE) derived from living adult Schistosoma mansoni confers high levels of resistance to challenge infection in mice and rabbits. We have carried out a number of experiments to analyse the composition of SE and to define the proteins that are rapidly released from the parasite. One of these proteins, with apparent molecular mass of 62 kDa, is recognized by polyclonal and monoclonal antibodies raised against high molecular mass cytokeratins from human epidermal cells. Immunocytochemical studies revealed a tegumental staining using the anti-cytokeratin antibody. Moreover, sera from schistosomiasis patients, as well as those from animals immunized with SE, were able to recognize this 62 kDa polypeptide as shown by immunoblot assays. These results suggest the existence of cytokeratin-containing filaments in the schistosome.

Animals↗

Predictive value of specific risk factors, symptoms and signs, in diagnosing obstructive sleep apnoea and its severity.

A positive diagnosis of obstructive sleep apnoea (OSA) is based on a combination of characteristic symptoms and polysomnographic findings. The present study evaluated the specificity and sensitivity of several risk factors, signs and symptoms in predicting an Apnoea Index in 86 patients referred to the sleep laboratory with suspected OSA. All 86 subjects completed a detailed questionnaire, were interviewed, underwent a brief physical examination, and then a whole-night polysomnographic study. Stepwise multiple regression analysis revealed that self reporting on apnoeas, neck circumference index (NCI), age, and a tendency to fall asleep unintentionally, were all significant positive predictors of apnoea index (AI), explaining 41.8% of the variability. The sensitivity of the model for predicting OSA (taking OSA as AI > 10) was 92.2%, specificity was 18.2% and the positive predictive value was 76.6%. Raising the cut-off AI values resulted in decreased sensitivity and increased specificity. Applying the predicting equation of AI to another group of 50 patients referred to the sleep laboratory with suspected OSA revealed similar results. However, running the equation on 105 offspring of OSA patients who did not complain of OSA-associated symptoms resulted in 32% sensitivity and 94% specificity in predicting OSA. It is concluded that questionnaires, interviews and physical examination, can only vaguely predict AI, and cannot replace polysomnographic recordings. However, the low rates of false negative in predicting AI > 10, and the low rates of false positive in predicting AI > 50, can be used for specific purposes.

Journal Article↗

Preservation of functioning human thyroid "organoids" in the severe combined immunodeficient mouse. III. Thyrotropin independence of thyroid follicle formation.

The severe combined immunodeficient (scid) mouse allows the in vivo reconstitution of thyroid follicles from thyroid monolayer cells when transplanted sc within an extracellular basement membrane matrix. After 2-3 weeks, these human thyroid organoids show an active microfollicular histology and secrete human thyroglobulin into the murine serum in response to the administration of recombinant human TSH. Furthermore, such organoids survive for more than 3 months in this functional state. To assess whether thyroid follicular reconstitution was TSH dependent, we examined organoid follicular reconstruction in T3-induced hyperthyroid scid mice, in which endogenous murine TSH was presumed to be totally suppressed. By providing water with 12 micrograms/ml T3, we increased the murine serum T3 levels from a mean of 1.9 nmol/liter in controls to greater than 12.0 nmol/liter. After 3 weeks, thyroid cells derived from normal human thyroid monolayers were suspended in an extracellular basement membrane matrix, and the suspension was transplanted sc into scid mice (with or without T3-induced hyperthyroidism) and allowed to reconstitute. Histological examination 4 weeks later showed a similar degree of thyroid follicle formation in mice treated with or without T3, indicating that the hyperthyroid state had caused no interference with thyroid follicle reconstitution. This was further confirmed by transmission electron microscopy, which demonstrated normal human thyroid follicle cell polarity in the organoids of both euthyroid and hyperthyroid mice. In addition, using an extracellular basement membrane preparation with reduced growth factor (epidermal growth factor, insulin-like growth factor-I, and platelet-derived growth factor) levels also allowed normal thyroid follicle formation in T3-fed mice. These data demonstrate that in vivo thyroid follicle formation is TSH independent and that extrathyroidal epidermal growth factor, insulin-like growth factor-I, and platelet-derived growth factor may be relatively unimportant. The factors and molecular mechanisms leading to follicular reorganization of adult human thyroid cells remain to be determined, but are likely to depend largely on intrathyroidal growth factor secretion and cell-cell interaction.

Animals↗

Abdominal ultrasonography in acute clinical schistosomiasis mansoni.

Abdominal ultrasonography was performed on eight children and four adults with acute schistosomiasis mansoni, 12 chronically infected patients, and 12 noninfected individuals from the endemic area, who were paired by age and sex with the acute group. In all acute patients, lymphadenomegaly as well as liver and spleen enlargement were detected. Lymph nodes surrounding the portal vein and the hepatic artery in the hepatic hilus were visualized. In the children, the right lobe of the liver was statistically significantly larger in the acute group than in the noninfected group. The portal and splenic vein diameters were significantly larger in children with acute schistosomiasis than in the chronically infected and negative control groups. The left hepatic lobe and a longitudinal scan of the spleen in acute adult patients were statistically significantly larger than in the chronically infected and negative control groups. Ultrasonography is shown to be a useful tool for the differential diagnosis of acute schistosomiasis mansoni.

Abdomen↗

Cell-mediated immunity to schistosomes. Evaluation of mechanisms operating against lung-stage parasites which might be exploited in a vaccine.

This report describes parallel studies examining T cell and cytokine responses to Schistosoma mansoni in mice and man. The prevalence of IFNg production amongst murine (C57BL/6) T cell lines and clones, plus good DTH reactivity by IFNg-secreting clones, highlights the predominance of the Th1 response in the pulmonary immunity characteristics of the murine irradiated vaccine model. In human studies, effects of anti-cytokine antibodies on the proliferation of PBMC from human patients to various soluble schistosome antigen preparations have been examined. Data suggest that both Th1 (against early antigens) and Th2 (against late antigens) responses are present. A role for IL-10 is highlighted in chronic intestinal, but not acute or chronic hepatosplenic patients, as a downregulator of responses which are associated with morbidity and are against late stage antigens.

Acute Disease↗

Gastric emptying. Comparison of anterior only and geometric mean correction methods employing static and dynamic imaging.

Dynamic (continuous) and static imaging techniques were compared in the analysis of gastric emptying patterns in 16 consecutive adult patients with normal gastric half-emptying times assessed by dynamic imaging for 90 minutes under a dual head camera allowing simultaneous anterior and posterior imaging. Gastric t1/2 values were calculated for each patient based on four different data analysis methods: geometric mean corrected dynamic data (GD), anterior alone dynamic data (AD), geometric mean corrected simulated static data (GS), and anterior alone simulated static data (AS). The mean t1/2 values were: GD = 63.8 minutes, AD = 72.1 minutes, GS = 65.3 minutes, and AS = 73.0 minutes. Both the geometric mean corrected methods had a statistically different t1/2 than either of the anterior methods. Lag phase measurements, defined as a 2% decrease in gastric activity were: GD = 7 minutes, AD = 19 minutes, GS = 6 minutes, and AS = 16 minutes. Dynamic and static geometric mean methods provide similar gastric t1/2 calculations that are statistically different than anterior alone methods, and the lag phase is much shorter using either of the geometric mean methods.

Female↗

The use of RAPDs for the study of the genetic diversity of Schistosoma mansoni and Trypanosoma cruzi.

Arbitrary primers have been used for the production of complex, PCR generated DNA profiles in order to undertake a preliminary random amplified polymorphic DNA (RAPD) analysis of strains (and related species) of two parasitic organisms that are responsible for important diseases endemic in Brazil: Schistosoma mansoni that causes schistosomiasis, and Trypanosoma cruzi that causes Chagas' disease. A relatively low level of polymorphism was found in S. mansoni when strains isolated from different regions of Brazil were compared, with less than 10% of bands exhibiting polymorphism. Comparison of different schistosome species, on the other hand, showed them to be distantly related with very few bands shared by even the more closely related species. Trypanosome strains were found to be much more variable. When strains were compared between zymodemes (groups of parasite strains with the same isoenzyme profiles), a maximum of 7% of bands were found to be common whereas among strains in the same zymodeme a clear characteristic pattern was observed. In the zymodeme most thoroughly studied, it was found that 59% of bands were shared. Band sharing analysis showed that the relationships of strains within a zymodeme correlate with their geographical origin and that the relationship between zymodemes correlates closely with that previously determined by isoenzyme analysis. These preliminary data indicate the ready applicability of RAPD analysis to the study of parasites where largely unexplored genetic variations may have an important bearing on the complexity and diversity of diseases.

Animals↗

The random amplification of polymorphic DNA allows the identification of strains and species of schistosome.

The use of arbitrarily selected primers (10-24 nucleotides) and very low stringency annealing conditions (30 degrees C followed by 40 degrees C) for the polymerase chain reaction amplification of 1.0 ng of schistosome DNA resulted in relatively complex patterns of products. Amongst the primers tested some, for example 5'-TCGTAGCCAA, produced patterns that included bands that were polymorphic between strains of Schistosoma mansoni. Other primers, for example 5'-TCACGATGCA, produced apparently identical products using DNA from 5 S. mansoni strains but highly variable patterns when DNA from different schistosome species was used. The results indicate that the random amplification of polymorphic DNA (RAPD) may be an extremely useful approach to the identification of schistosome strains and species.

Animals↗

The effects of danazol on a patient with familial dysalbuminemic hyperthyroxinemia.

Familial dysalbuminemic hyperthyroxinemia, a syndrome involving an abnormal affinity of albumin for thyroxine, results in elevated total thyroxine and free thyroxine index levels but normal triiodothyronine resin uptake and thyroid-stimulating hormone levels. Danazol is a synthetic androgen that increases triiodothyronine resin uptake and decreases total thyroxine, secondary to a decrease in thyroid-binding globulin levels. A 35-year-old woman with familial dysalbuminemic hyperthyroxinemia who was given danazol, in whom nervousness, insomnia, and weight gain developed, is described. Thyroid tests performed after initiation of danazol therapy revealed an increase in triiodothyronine resin uptake, with persistently elevated total thyroxine and free thyroxine index levels, and normal thyroid-stimulating hormone levels. Once the danazol was withdrawn, the symptoms resolved, the triiodothyronine resin uptake returned to normal, and the thyroid-stimulating hormone remained normal. The effects of danazol on a patient with familial dysalbuminemic hyperthyroxinemia correlate well with the effects on normals, and the ultrasensitive thyroid-stimulating hormone was the most useful test in separating hyperthyroxinemia from hyperthyroidism.

Adult↗

Discrimination between periportal and pericentral necrosis of rat liver by determination of glutamine synthetase and other enzyme activities in serum.

Periportal or pericentral necrosis of rat liver was produced by injection of allyl-alcohol or bromobenzene, respectively. Activities of predominantly periportal and perivenous enzymes were determined in serum during maximal necrosis. Aspartate aminotransferase, which is more or less homogeneously distributed in the liver acinus, exhibited similar activities in serum after periportal and pericentral injury. Serum activities of the mainly periportal enzymes alanine aminotransferase and fructose 1,6-bisphosphatase were 1.5- to 2-fold higher after periportal as compared to pericentral necrosis. Serum activity of the mainly pericentral glutamate dehydrogenase was 3-fold higher after pericentral than after periportal damage. However, due to individual variations necrosis could not be definitively localized in any case by measurement of these enzyme activities. Better discrimination between periportal and pericentral necrosis was achieved by the serum activity of the exclusively pericentral enzyme glutamine synthetase, which was 8-fold higher after pericentral as compared to periportal necrosis. Conclusive discrimination was obtained by the activity ratio fructose 1,6-bisphosphatase/glutamine synthetase in serum.

Alanine Transaminase↗

[Urban focus of schistosomiasis in a metropolitan area in a southeastern region of Brazil].

Urban focus of schistosomiasis in an urban area of South-eastern, Brazil. An active, urban focus of schistosomiasis in Belo Horizonte, MG, Brazil is described. It is located in the "Julien Rien" Park, a leisure area of 48,500 m2 created by the local administration in 1980 on the south side of city. Snail captures were made over 10 years (1983-1992) resulting in the collection of 3,361 Biomphalaria glabrata, ranging from 6.4 to 12.8 mm in diameter (mean = 9.3); 23 (0.7%) of these were found to be infected with Schistosoma mansoni. The finding of S. mansoni intermediate hosts in urban areas (ponds, small artificial lakes, etc) may be related to the introduction of fish and ornamental aquatic plants coming from specialized shops or areas in which they occur. It is suggested that the introduction of fish aquatic plants into urban water collections without a quarantine period should be avoided, as a prophylactic measure.

Animals↗

Secretion of plasma proteins and its insulin-dependent regulation in rat hepatocyte-hepatoma hybrid cells.

Hepatocyte-hepatoma hybrid cells were obtained by fusion of primary rat hepatocytes with Fao hepatoma cells. Synthesis and secretion of the liver-specific plasma proteins albumin and transferrin were preserved in these proliferating hybrids, called hepatocytoma cells. In the hybrid clone 1E3, secretion of albumin was 75% and that of transferrin was 45% of the secretion in normal hepatocytes. The level of albumin mRNA was fivefold higher in hepatocytoma cells than in normal hepatocytes. Essentially no albumin and transferrin secretion or albumin mRNA was found in the parental Fao hepatoma cells. Insulin decreased the albumin mRNA level in hybrid cells, while it increased the level in normal hepatocytes. This indicates an inverse effect of the hormone due to this regulation in immortalized hepatocytoma cells compared to normal hepatocytes.

Animals↗

A 13-year follow-up of treatment and snail control in an area endemic for Schistosoma mansoni in Brazil: incidence of infection and reinfection.

The incidences of Schistosoma mansoni infection and reinfection were investigated in an endemic area of Brazil (Peri-Peri, State of Minas Gerais) where chemotherapy and snail control had been used for 13 years (1974-87). Two cohorts were followed: the first consisted of 584 individuals with no evidence of infection at entry (infection cohort), and the second comprised 296 individuals who were treated and did not eliminate eggs 8-12 months afterwards (reinfection cohort). The incidence of infection (per 100 person-years) decreased from 7.5 in 1974-77 to 3.6 in 1986-87, and that of reinfection from 21.3 in 1974-77 to 3.7 in 1986-87. Calendar period, age at risk, and sex were independently associated with both infection and reinfection, while a heavy S. mansoni egg count prior to treatment (> or = 500 epg (eggs per gram of stools)) was independently associated with reinfection. The geometric mean number of eggs after treatment among those reinfected (47 epg) was approximately half that among those infected for the first time (81.5 epg). Age at risk had the greatest effect on both infection and reinfection. The rate ratios of infection and reinfection were 3 to 6 times higher among individuals younger than 20 years than among those aged > or = 25 years, even after adjusting for confounders. This suggests the existence of a strong protective effect with increased age (because of biological and/or environmental factors) for both infection and reinfection.

Adolescent↗