[Geographical factors in the epidemiology of intoxication with Karwinskia (tullidora) in Mexico]. / Factores geográficos en la epidemiología de la intoxicación por Karwinskia (tullidora) in México.

Consumption of fruits from the genus Karwinskia may cause a flaccid paralysis that can be confused with the Guillan-Barré syndrome or poliomyelitis. Paralysis resulting from consumption of such fruit has emerged as a public health problem in certain regions of Mexico. The purpose of this study was to investigate geographical factors associated with this intoxication in the 72 cases reported in Mexico from 1990 to 1994. Location of cases coincides with the distribution of the 11 reported species of Karwinskia in the country. The majority of reported cases were related to the consumption of K. humboldtiana, with a smaller number involving K. mollis, K. parvifolia, K. johnstonii, and K. rzedowskii. Most cases were located in regions with dry climates (79.2%), arid vegetation (41. 7%), and altitudes under 1,000 meters above sea level (54.1%). The study establishes three different risk areas: the Balsas river region in the southwestern central part of the country; the arid northern area; and the arid and dry central area. Cases were from rural communities with low levels of schooling and poor socioeconomic conditions.

Accuracy of biopsy and cytology for the preoperative diagnosis of colorectal adenocarcinoma.

BACKGROUND AND OBJECTIVES: Endoscopic biopsy for the diagnosis of colorectal adenocarcinoma is not accurate in every case. Brush cytology can increase the sensitivity for the diagnosis of gastroesophageal lesions when combined with biopsy, but very little information is available for these techniques in the diagnosis of colorectal adenocarcinoma. METHODS: A retrospective medical records review of 110 patients was performed. All patients underwent a colorectal resection for primary adenocarcinoma after a diagnostic endoscopy. Biopsy and brush cytology was evaluated for their respective sensitivity. Seventy-three patients had both biopsy and cytology. RESULTS: The sensitivity of biopsy was 83.6% (92/110); for cytology, 78.1% (57/73; P = 0.44). From the 73 patients who had both diagnostic techniques, 68.5% (50/73) had both positive biopsy and cytology, 12.3% (9/73) only a positive biopsy, and 9.6% (7/73) only a positive cytology. The two techniques combined were not significantly superior to biopsy alone (90.4%, 66/73, vs. 80.8%, 59/73, respectively; P = 0.16), but tended to be superior to cytology alone (P = 0.07). CONCLUSIONS: Cytology and biopsy have a comparable sensitivity. The combination of the two techniques compares favorably, but does not significantly increase the sensitivity of biopsy alone. Both techniques should be used whenever there are any uncertainties concerning the diagnosis of colorectal adenocarcinoma.

[Persistent symptomatology in workers industrially exposed to organophosphate pesticides]. / Sintomatología persistente en trabajadores industrialmente expuestos a plaguicidas organofosforados.

OBJECTIVE: To describe the patterns of persistent symptomatology in workers industrially exposed to organophosphate pesticides. MATERIAL AND METHODS: An observational, descriptive and cross-sectional study was performed. A questionnaire was applied to managers of a factory and to 89 workers, whose erythrocytic cholinesterase level was measured with the Magnotti and Lovibond method. Information is described through rates, central tendency measures and dispersion. Differences between groups were evaluated with the chi 2 test and the odds ratio was calculated. RESULTS: Persistent symptomatology was found in 6.3 per 10 workers. 50% had six or more symptoms. No significant differences were found as to the risk of suffering from persistent symptomatology with respect to age, length of service or position at work. However, the highest proportion of symptoms was found in workers of 31 to 40 years of age, with 6 to 13 years of service, from the maintenance area, working as general operators or supervisors. Among the 13 workers with previous intoxication, the prevalence of persistent symptomatology was 6.9 against 6.1 in workers who had not been intoxicated before. The risk of acute poisoning in workers with more than 14 years of service was 4 times greater than in workers with less than 14 years of service (p < 0.005). Average level of blood cholinesterase was normal (4.4 u/ml). CONCLUSIONS: Results show a relationship between exposure to organophosphate pesticides and presence of persistent symptoms. It is necessary to study the prevalence of this symptomatology in exposed and non-exposed populations.

Specimen mammography-guided fine-needle aspirates of mammographically normal fatty and dense benign tissue: analysis of cell number and type.

Specimen mammography-guided 20-gauge fine-needle aspirates (FNA) were obtained from normal dense or fatty tissue. Single aspirates of dense tissue yielded greater cell counts; 74% (32 of 43) had greater than 5,000 cells as compared to 20% (19 of 93) of fatty tissue FNA, p < 0.05. Dense tissue FNA also yielded greater percentages of epithelial cells; 95% (21 of 22) had greater than 50% epithelial cells as compared to 43% (17 of 40) of fatty tissue FNA, p < 0.05. Mammographic guidance toward dense tissue is suggested for clinical studies of risk assessment using FNA of normal breast tissue.

Specimen mammography-guided fine-needle aspirates of clinically occult benign and malignant lesions. Analysis of cell number and type.

RATIONALE AND OBJECTIVES: The authors determine the cell counts and percentages of epithelial cells in fine-needle aspirates (FNA) of mammographically detected breast lesions. METHODS: Specimen mammography-guided 20-gauge fine-needle aspirations were performed on 151 consecutive lesions. Cell counts were determined by flow cytometry of 106 consecutive aspirates. Semiquantitative determination of the percentage of epithelial cells was done by cytologic analysis of 151 aspirates. RESULTS: Single FNA cell counts were greater than 1000 for all lesions and greater than 7000 in 57% (31 of 54) of malignant and 35% (18 of 52) of benign lesions, P = 0.02. Fine-needle aspirates of soft tissue abnormalities had more than 7000 cells in 59% (27 of 46) of specimens, compared with 36% (22 of 61) in calcifications, P < 0.05. With the exception of fibroadenomas, the mammographic appearance of benign lesions, lesion size, and patient age had no association with cell counts. Ninety-three percent (76 of 82) of malignant lesion FNA and 80% (55 of 69) of benign lesion FNA had 50% or greater epithelial cells, P < 0.05. CONCLUSIONS: Fine-needle aspiration yields abundant cell counts of predominantly epithelial cells from most types of mammographically detected lesions and should be considered as a source of fresh cell samples for the study of benign and early malignant breast disease.

Herpes simplex viral pneumonia in the postthoracotomy patient.

Over a 6-month period, 6 of 54 postthoracotomy patients developed pneumonia and respiratory failure. Pneumonia was secondary to herpes simplex virus type 1 in 3 of the 6 patients. Diagnostic efforts including bronchoscopy with bronchial washing, viral cultures, and cytologic examination permitted early diagnosis and successful treatment with acyclovir. A high index of suspicion for herpes simplex pneumonia must be maintained in critically ill patients with undiagnosed pneumonia.

Flow cytometric DNA analysis of excised breast lesions: use of fresh tissue needle aspirates obtained under guidance with mammography of the specimen.

Eighty consecutive biopsy specimens were studied to determine whether DNA analysis could be performed on fine-needle aspirates of excised clinically occult breast lesions obtained under guidance with mammography of the specimen before fixation to offer the advantages of fresh-tissue analysis. With use of single aspirates, cytologic analysis was possible in 50 cases (62%); DNA analysis was possible in 75 cases (94%). These methods combined offered no statistically significant increase in sensitivity for detection of malignancy compared with cytologic analysis alone. Forty-one percent of the analyzable invasive carcinomas showed aneuploidy. Aneuploidy and high S phase fractions of the invasive carcinomas showed no substantial correlation with patient age, nodal status, and size or appearance of the mammographic lesion. Aneuploidy was also seen in zero of four analyzable lesions showing ductal carcinoma in situ, two of 13 showing atypical hyperplasia (15%), and one of the 28 remaining benign lesions (4%). The authors conclude that this mammographic intervention is an effective means of obtaining fresh tissue samples of clinically occult lesions for DNA analysis.

Reaction of cytochrome c in the electron-transport chain of Paracoccus denitrificans.

The reaction of the cytochrome c oxidase (ferrocytochrome c:oxygen oxidoreductase, EC 1.9.3.1) of Paracoccus denitrificans cytoplasmic membranes with the endogenous cytochrome c of the membranes was studied, as well as its interaction with added exogenous cytochrome c from P. denitrificans or bovine heart. The polarographic method was employed, using N,N,N',N'-tetramethyl-p-phenylenediamine plus ascorbate to reduce the cytochrome c. We found that overall electron transport can proceed maximally while the cytochrome c remains membrane bound; NADH or succinoxidase activities were not inhibited by the addition of substances which bind the P. denitrificans cytochrome c strongly. In contrast to our observations with the spectrophotometric method (Smith, L., Davies, H.C. and Nava, M.E. (1976) Biochemistry 15, 5827-5831), in the polarographic assays the membrane-bound oxidase reacts with about equal rapidity with exogenous bovine and P. denitrificans cytochromes c. The reaction of the oxidase with the endogenous cytochrome c proceeds at high rates and preferentially to that with exogenous cytochrome c; the reaction with the latter, but not the former is inhibited by positively charged poly(L-lysine). The cytochrome c and the oxidase appear to be very closely associated on the membrane.

The reaction of the trifluoromethylphenylcarbamylated lysine-13 derivative of horse cytochrome c with cytochrome oxidase.

The kinetics of oxidation of horse cytochrome c and the trifluoromethylphenylcarbamylated lysine-13 derivative by cytochrome c oxidase (ferrocytochrome c: oxygen oxidoreductase, EC 1.9.3.1) were compared using both spectrophotometric and polarographic methods under different experimental conditions. The rate constants measured spectrophotometrically in 0.025 M tris-cacodylate buffers were similar with the two cytochrome at pH 7.8, but those with the derivative were slightly higher at pH 6. Rates measured with polarographic assays in these buffers were the same with the horse and the derivative cytochromes c at pH 6, but at pH 7.8 the rates with the derivative were less at cytochrome c concentrations between 0.05 and 0.5 micro M and were greater at higher concentrations. The pH optima in the polarographic assays of the derivative and the native pigments were different in 0.025 M Tris-cacodylate buffers; in spectrophotometric assays at pH 7.8 the trifluoromethylphenylcarbamylated lysine-13 cytochrome c showed a greater sensitivity to changes in ionic strength than did the native cytochrome. The variations in apparent Km and V values calculated from spectrophotometric and polarographic assays with the two cytochromes cannot be explained as due to changes in binding of cytochrome c to cytochrome oxidase. The large excess of O2 uptake seen in polarographic assays with horse cytochrome c over that expected from spectrophotometric measurements was not apparent with the trifluoromethylphenylcarbamylated lysine-13 derivative. Thus, the derivative seems to have decreased ability to form the combination of cytochrome c with the oxidase giving high turnover rates.

Induction of mixed function oxidases by petroleum in the American eel, Anguilla rostrata.

American eels, Anguilla rostrata, were exposed to crude oil by ingestion of a 10, 100, or 500 microliters/kg fish dose per day for five days. Depuration was followed for an additional twelve days. All oil doses caused an induction of hepatic microsomal enzymes, maximally by three days of exposure. Benzo(a)pyrene hydroxylase (BaPH) showed a dose related response, with greater induction at 100 microliters/kg than at the other doses. The highest dose was hepatotoxic. Cytochrome P-450 induction was dose independent, and remained induced maximally for the entire experimental period, in contrast to BaPH which declined in activity. Reaction optimum for BaPH was at pH 7.5 and 27 degrees C. A study of tissue distribution showed the liver to account for nearly all BaPH activity. A significant increase in the protein content of the hepatic postmitochondrial fraction of oil-exposed fish was also observed.

Effect of adenosine 5'-triphosphate and adenosine 5'-diphosphate on the oxidation of cytochrome c by cytochrome c oxidase.

Adenosine 5'-triphosphate (ATP), adenosine 5'-diphosphate (ADP), and inorganic pyrophosphate partially inhibit the oxidation of exogenous cytochrome c by cytochrome c oxidase of submitochondrial particles (with or without detergent treatment) or by a purified preparation when it is assayed polarographically in buffers of nonbinding ions at pH 7.8. ATP is somewhat more inhibitory than ADP. The inhibition is never greater than 50%, and it is always less than an equal concentration of Mg2+ ions is present or when the assays are run at pH 6. In contrast, the effect of ATP, ADP, and pyrophosphate on oxidase assays run spectrophotometrically is a similar slight stimulation of the oxidase of submitochondrial particles treated with deoxycholate and little or no effect on purified oxidase. The reaction of the oxidase of submitochondrial particles with the endogenous cytochrome c is stimulated by the nucleotides, as is the reduced nicotinamide adenine dinucleotide (NADH) oxidase activity. The observations can be explained by binding of ATP, ADP, or pyrophosphate to cytochrome c so that the formation of an especially reactive combination of cytochrome c and cytochrome oxidase previously postulated [Smith, L., Davies, H. C., & Nava, M. E. (1979) Biochemistry 18, 3140] is prevented. The data give no evidence that respiration via cytochrome c oxidase is regulated physiologically by direct effects of ATP or ADP on its activity.