Biomedical subjects

M Blanco

Publications and source records attributed to M Blanco.

At least 127 records · Page 7Linked to original sources

PubMed1997

Detection of pap, sfa and afa adhesin-encoding operons in uropathogenic Escherichia coli strains: relationship with expression of adhesins and production of toxins.

A total of 243 Escherichia coli strains isolated from patients with urinary tract infections (UTI) were investigated for the presence of pap, sfa and afa adhesin-encoding operons by using the polymerase chain reaction. It was found that 54%, 53% and 2% of the strains exhibited the pap, sfa and afa genotypes, respectively. Pap+ and/or sfa+ strains were more frequent in cases of acute pyelonephritis (94%) than in cases of cystitis (67%) (P < 0.001) and asymptomatic bacteriuria (57%) (P < 0.001). The pap and/or sfa operons were found in 90% of strains expressing mannose-resistant haemagglutination (MRHA) versus 37% of MRHA-negative strains (P < 0.001). The presence of pap and sfa operons was especially significant in strains belonging to MRHA types III (100%) (without P adhesins) and IVa (97%) (expressing the specific Gal-Gal binding typical of P adhesins). Both pap and sfa operons were closely associated with toxigenic E. coli producing alpha-haemolysin (Hly+) and/or the cytotoxic necrotizing factor type 1. There was an apparent correlation between the pap and sfa operons and the O serogroups of the strains. Thus, 93% of strains belonging to O1, O2, O4, O6, O7, O14, O15, O18, O22, O75 and O83 possessed pap and/or sfa operons, versus only 32% of strains belonging to other serogroups (P < 0.001). The results obtained in this study confirm the usefulness of our MRHA typing system for presumptive identification of pathogenic E. coli exhibiting different virulence factors. Thus, 85% of strains that possessed both pap and sfa adhesin-encoding operons showed MRHA types III or IVa previously associated with virulence of E. coli strains that cause UTI and bacteraemia.

Adhesins, Escherichia coli↗

PubMed1997

Ranitidine versus colloidal bismuth subcitrate in combination with amoxicillin and metronidazole for eradicating Helicobacter pylori in patients with duodenal ulcer.

One hundred twenty-two patients were randomly assigned to three groups of treatment (A, B, and C), with (1) ranitidine (300 mg q.d. for 6 weeks), (2) ranitidine (300 mg q.d. for 6 weeks) with amoxicillin (500 mg t.i.d.) and metronidazole (500 mg b.i.d.) for the first 12 days, or (3) colloidal bismuth subcitrate (120 mg q.i.d. for 6 weeks) with amoxicillin and metronidazole (at same dosages as in the latter group). Six weeks after the beginning of treatment, an endoscopy showed that ulcers had healed in 49 of 52 patients (94.2%) from whom Helicobacter pylori had been eradicated and in 59 of 70 patients (84.3%) from whom it had not (NS). The rates of H. pylori eradication in groups A, B, and C were zero, 47.5%, and 86.8%, respectively. At 6, 12, and 18 months, an endoscopy was repeated for monitoring ulcer recurrence and H. pylori status. Reinfection rates at 6 months were 42.1% and 15.1% in groups B and C, respectively (P < .05). At 18 months, ulcers recurred in 82.9% (63) of 76 patients with noneradicated H. pylori infection, vs. 5.7% (2) of 35 patients without H. pylori infection (P < .001). We conclude that colloidal bismuth subcitrate is more effective for eradication of H. pylori than ranitidine when given with amoxicillin plus metronidazole for the treatment of duodenal ulcer, as both early reinfection and ulcer recurrence are diminished.

Adolescent↗

PubMed1997

Dopaminergic influence on cardiovascular responses to exercise stress in hypertensive subjects.

Ten hypertensive subjects were studied at the Vargas Medical School in Caracas, Venezuela. They were submitted to submaximal treadmill exercises according to Bruce's protocol under treatment with dopaminergic drugs (metoclopramide, bromocriptine). Before and during submaximal exercises, metoclopramide caused a hypotensive effect accompanied by an increased heart rate, which was blocked by the administration of bromocriptine. We conclude that a probable dopaminergic modulatory influence takes place during exercise.

Blood Pressure↗

PubMed1997

The cold pressor test: pharmacological and therapeutic aspects.

In this review article we discuss several aspects of the physiology, diagnosis, and pharmacology of the cold pressor test. The cold pressor test has been used for the diagnosis of cardiovascular reactivity in normotensive and hypertensive subjects. Some authors have stated that the cold pressor test will identify normotensive candidates at future risk of suffering from hypertensive disease. Interestingly, not all antihypertensive drugs block the exaggerated pressor response induced by cold stress. The most beneficial compounds belong to the alpha- and beta-blocker groups. Furthermore, several neurohormones such as norepinephrine, endothelins, prostaglandins, and angiotensin II have been reported to be released during cold exposure. The neurophysiology of cold pressor test indicates that after stress a great sympathetic discharge is induced at the spinal cord and terminal endings of the sympathetic nervous system. The release of norepinephrine is the cause of arteriolar vasoconstriction and elevation of blood pressure.

Antihypertensive Agents↗

PubMed1997

Prevalence and characteristics of enteropathogenic Escherichia coli with the eae gene in diarrhoeic rabbits.

A field study was carried out with the objective of investigating the prevalence of enteropathogenic Escherichia coli (EPEC) with the eae gene in diarrhoeic rabbits. EPEC eae+ were isolated from 60 (74%) of 81 diarrhoeic rabbits sampled in 30 industrial fattening farms localized in the four provinces of Galicia (northwestern Spain). Attaching and effacing lesions were found in 44 of 50 animals processed for histology. The 111 E. coli strains identified belonged to 19 different O serogroups and 13 biotypes. However, 53 (48%) of the strains belonged to serogroup O103 and 36 (32%) showed the serobiotype O103:B14. The eae gene was significantly more frequent (100%; 47 of 47) among the highly pathogenic rhamnose-negative strains of serobiotypes O103:B6 and O103:B14 than among the E. coli strains belonging to other serobiotypes (36%; 23 of 64) (P < 0.001). In this first report about the prevalence of EPEC with the eae gene in rabbits, we conclude that the class of E. coli strains observed is a common cause of diarrhoea in Galician rabbit farms, and that highly pathogenic rhamnose-negative strains of serotype O103:K-:H2 and biotype B14 are specially predominant.

Adhesins, Bacterial↗

PubMed1997

Production of toxins (enterotoxins, verotoxins, and necrotoxins) and colicins by Escherichia coli strains isolated from septicemic and healthy chickens: relationship with in vivo pathogenicity.

Since the mechanism of virulence of Escherichia coli strains pathogenic to birds is not fully understood, the prevalence of toxic factors produced by E. coli strains pathogenic to other animals was investigated. A total of 625 E. coli strains isolated from visceral organs of chickens with colisepticemia and from feces of healthy chickens in Spain were tested for production of enterotoxins (heat labile [LT] and heat stable [STa]), verotoxins (VT1, VT2, and VT2v), cytotoxic necrotizing factors (CNF1 and CNF2), alpha-hemolysin (Hly), enterohemolysin (EntHly), colicin V (Col V) and other types of colicins, and necrotic and lethal activities. Only 45 (7%) of avian E. coli strains were toxigenic: 20 strains produced a cytotoxic response in HeLa but not in Vero cells, indicating the production of a cytotoxin not related to the VTs; 16 were EntHly+; 5 produced a new cytotonic product that causes the appearance of whitish vacuola in Vero and HeLa cells; 3 synthesized soluble factors that cause lethal activity in mice; and 1 elaborated LT. None of 625 avian E. coli strains was positive for production of VTs or CNFs. In contrast, colicinogenicity occurred in 335 (73%) of the 458 septicemic strains and 97 (58%) of 167 fecal isolates (P < 0.01), and this property was correlated with in vivo pathogenicity of strains. Thus, 80% (P < 0.001) and 66% (P < 0.001) of strains producing Col V and other types of colicins were characterized as being of high pathogenicity, whereas only 15% of the noncolicinogenic strains were classified as highly pathogenic. Our results clearly support the special pathogenicity theory, because 60% of the E. coli strains belonging to 18 serogroups (O1, O2, O5, O8, O12, O14, O15, O18, O20, O53, O78, O81, O83, O102, O103, O115, O116, and O132) most frequently identified among clinical septicemic strains were classified as highly pathogenic in in vivo assays, whereas only 24% of the strains with O serogroups less prevalent among diseased chickens were considered highly pathogenic (P < 0.01).

Animals↗

PubMed1997

Genes coding for enterotoxins and verotoxins in porcine Escherichia coli strains belonging to different O:K:H serotypes: relationship with toxic phenotypes.

Seventy-four E. coli strains isolated from piglets with diarrhea or edema disease in Spain were serotyped and examined for production of heat-labile (LT) and heat-stable (ST) enterotoxins (LT-I, LT-II, STaH, STaP, and STb) and verotoxins (VT1, VT2, and VT2v = VTe) by phenotypic (Vero cell assay and infant mouse test) and genotypic (colony hybridization and PCR) methods. In general, an excellent correlation was found between the results obtained with a PCR approach and those determined with biological assays. DNA probes used in the hybridization also showed a very good agreement with phenotypic results, with the exception of a VT1 probe that initially produced 10 false-positive reactions. The gene coding for STb (58 strains) was the most prevalent gene detected by PCR, followed by those coding for STa (46 strains), LT (19 strains), VT2v (11 strains), and VT1 (1 strain). Apparently, in Spain three seropathotypes are predominant: (i) O149:K91:H10 K88+ LT-I+ STb+, (ii) O141:K85ab:H- P987+ STaP+, and (iii) O138:K81:H14 or H- STaP+ VT2v+. We conclude that PCR is a fast, specific, and practical method for the identification of enterotoxin and VT genes in clinical and epidemiological studies.

Animals↗

PubMed1997

Prevalence of bacterial resistance to quinolones and other antimicrobials among avian Escherichia coli strains isolated from septicemic and healthy chickens in Spain.

Antimicrobial therapy is an important tool in reducing the enormous losses in the poultry industry caused by Escherichia coli infections (colibacillosis). However, resistance to existing antimicrobials is widespread and of concern to poultry veterinarians. Antimicrobial resistance testing of 468 avian E. coli strains isolated in Spain showed very high levels of resistance to trimethoprim-sulfamethoxazole (67%) and the new fluoroquinolones (13 to 24%). As these antimicrobial agents may cause cross-resistance with human enteric pathogens, prudent use of them in veterinary medicine is highly recommended.

4-Quinolones↗

PubMed1996

Induction of SOS-independent mutations by benzo[a]pyrene treatment in Escherichia coli cells deficient in MutY or MutM DNA glycosylases: possible role of oxidative lesions.

The induction of SOS-independent mutations by exposure to benzo[a]pyrene (BaP) was screened in Escherichia coli strains lacking SOS mutagenesis proteins and deficient in MutY or MutM glycosylases, which prevent mutations by 8-hydroxyguanine (GO lesion). Mutagenicity assays, performed in the presence of S9 mix, indicated a great increase in the reversion of the trpE65 ochre mutation in both mutY and mutY mutM strains, whereas a lower increase was observed in a mutM strain. This mutability by BaP was observed in either uvr- or uvr+ strains. Moreover, it was increased when strains carried a deletion of the oxyR gene that abolished the OxyR response to oxidative stress, and reduced in the presence of the oxyR2 allele that rendered constitutive such response. It is suggested that SOS-independent mutations in cells treated with BaP arise from adenine/GO mispairs. The interaction of radical scavengers with BaP ultimate metabolites could cause oxidative stress capable of producing GO lesions. Strains lacking mutagenesis proteins and deficient in base excision repair systems, such as those dependent on MutY and MutM glycosylases, could be useful for screening the induction of SOS-independent mutations.

Adenosine Triphosphatases↗

PubMed1996

Specificity of spontaneous and t-butyl hydroperoxide-induced mutations in delta oxyR strains of Escherichia coli differing with respect to the SOS mutagenesis proficiency and to the MutY and MutM functions.

Mutations induced by oxidative DNA damage appear to occur by two pathways, differing in their dependence on SOS mutagenesis. We have analysed the specificity of mutations produced by each pathway. Base substitutions generating extragenic suppressors were characterized in Trp+ revertants of Escherichia coli strains carrying the trpE65 ochre mutation, which were hypersensitive to oxidative mutagenesis due to a deletion of the oxyR gene. In strain IC3821, containing MucA/B proteins and therefore proficient for SOS mutagenesis, the more frequently scored base substitutions, either spontaneous or induced by t-butyl hydroperoxide (BuOOH), were T:A-A:T transversions, followed by G:C-A:T transitions, while the frequency of G:C-T:A transversions was lower. This SOS-dependent mutability could be promoted by abasic sites. In strains IC3894 (mutY) and IC3981 (mutY mutM), lacking mutagenesis proteins, SOS-independent revertants arose almost exclusively via G:C-T:A transversions probably derived from oxidatively damaged 8-oxoguanine/adenine mispairs. Formation of these mispairs in IC3894 and IC3981 would be enhanced by BuOOH treatment since it caused a significant increase in the revertant number. Strains IC3894 and IC3981 could have a complementary role to that of IC3821 to analyse the mutagenicity and the mutational specificity of oxidants.

DNA Glycosylases↗

PubMed1996

Prevalence and characteristics of human and bovine verotoxigenic Escherichia coli strains isolated in Galicia (north-western Spain).

An epidemiological study was carried out to determine the incidence and the serotypes of verotoxigenic Escherichia coli (VTEC) that cause infections in Galicia (north-western Spain). Although, VTEC strains were isolated from 55 (14%) of the 387 calves sampled and the majority of bovine VTEC strains belonged to serotypes (026:H11 or H-, 091:H21, O103:H2, 0105:H18, O111:H-O113:H21, O126:H-, O128:H- and O157:H7 or H-) previously associated with human haemorrhagic colitis (HC) and haemolytic uraemic syndrome (HUS) in other countries, VTEC are not a common cause of human infections in Spain. Thus, VTEC (O26:H11 and O86:H10) were isolated from only 3 (0.6%) of the 482 children with diarrhoea investigated. We examined the 69 (3 humans and 66 bovines) VTEC strains that were initially isolated as E. coli producing a toxin cytotoxic to Vero and HeLa cells by polymerase chain reaction (PCR) using specific primers for VT1, VT2 and eae genes. PCR showed that 38 (55%) of VTEC strains carried VT1 genes. 18 (26%) possessed VT2 genes, and 10 (14%) carried both VT1 and VT2 genes. Three (one human and two bovine) strains which were formerly VTEC had lost the ability to produce verotoxins upon subculture and became negative for VT1 and VT2 by PCR. In total 35 (51%) of 69 VTEC strains, including the two human VT1+ strains of serotype O26:H11, were positive for eae sequences when tested by PCR. Presence of the eae gene was significantly more frequent (100%; 21/21) among VTEC strains with serotypes (O26:H11, O111:H-, O157:H-and O157:H7) considered as enterohaemorrhagic E. coli (EHEC) than among VTEC strains with non-EHEC serotypes (29%; 14/48) (p < 0.001). Results obtained in this study indicate that cattle may be an important source of VTEC involved in human disease. However, severe clinical syndromes caused by VTEC, such as HC and HUS, are uncommon in Spain, in comparison with North America and the UK. In any case, VTEC disease can appear on the scene very suddenly, as occurred in the UK and North America in the 1980s.

Animals↗

PubMed1996

Virulence factors and O groups of Escherichia coli isolates from patients with acute pyelonephritis, cystitis and asymptomatic bacteriuria.

The relationship between the presence of bacterial virulence factors and the severity of urinary tract infection (UTI) was analized in this study. The production of alpha-hemolysin (Hly), the expression of P-fimbriae and the mannose-resistant hemagglutination (MRHA) type IVa (associated with the presence of P-fimbriae), were all detected more frequently in Escherichia coli strains from acute pyelonephritis than in strains isolated from cystitis and asymptomatic bacteriuria. In contrast, the production of cytotoxic necrotizing factor type 1 (CNF1) and the expression of MRHA types III and IVb were distributed uniformly between strains causing different clinical categories of UTI. Thus 88% of the E. coli strains from acute pyelonephritis showed some of the virulence factors investigated in this study, whereas only 60% (p < 0.01) and 56% (p < 0.01) repectively of the strains isolated from cystitis and asymptomatic bacteriuria possessed virulence factors. There were no significant differences in the prevalence of virulence properties between strains isolated from patients with or without complicating factors. Only 16% (p < 0.001) of the fecal isolates from healthy individuals showed virulence factors. The virulence factors were concentrated in strains belonging to 10 (O1, O2, O4, O6, O7, O14, O18, O22, O75 and O83) of the 12 serogroups most frequently detected in uropathogenic E. coli strains. The majority of uropathogenic O4, O6, O14, O22, O75 and O83 E.coli strains were Hly+CNF1+ and expressed P-fimbriae or MRHA type III, whereas the strains of serogroup O18 were Hly+CNF1- and P-fimbriated. Among O1 and O7 strains we found Hly-CNF1-strains that expressed P-fimbriae. Among O2 strains we found Hly+CNF1+ strains that expressed P-fimbriae or MRHA type III and other Hly-CNF1-strains that possessed P-fimbriae. We conclude that E.coli strains isolated from pyelonephritis show virulence factors more frequently than those from cystitis and asymptomatic bacteriuria, and that strains that cause urinary tract infections in Spain belong to the same serogroups as uropathogenic E.coli isolated in other areas of the world. Our results support the special pathogenicity theory and suggest that many cases of serious urogenital disease may be caused by a limited number of P-fimbriated E.coli strains that usually produce alpha-hemolysin.

Acute Disease↗

PubMed1996

Severe congenital limb deficiencies, vertebral hypersegmentation, absent thymus and mirror polydactyly: a defect expression of a developmental control gene?

We describe two unrelated patients with a complex malformation pattern that may be a candidate for a developmental gene disorder. These two patients had severe, symmetrical upper and lower limb deficiencies, vertebral hypersegmentation, and duodenal atresia. Patient 1 also had mirror-image polydactyly of his feet; patient 2 was athymic. The concurrence in two unrelated patients of additional vertebrae with severe anomalies in limb development, including a symmetrical deficiency of the four limbs and either mirror-image duplication of some toes (only in patient 1) or absence of the thymus (only in patient 2), represents an early alteration in body-plan organization. Since limb development, thymus development and segmentation are possibly under the control of homeobox genes in the human embryo, it seems reasonable that the malformations observed in these two patients resulted from a defect of a gene controlling developmental pattern formation, possibly a homeobox gene or a paired-box gene. Severe limb deficiencies have been reported in other well-known genetic entities, such as Roberts syndrome, Baller-Gerold syndrome, X-linked amelia, and DK-phocomelia syndrome. However, since the specific pattern of anomalies observed in these patients makes the diagnosis of some of the abovementioned disorders unlikely, we conclude that our patients have a previously undescribed disorder.

Abnormalities, Multiple↗

PubMed1996

Serogroups of Escherichia coli isolated from piglets in Spain.

Serogroups of 1334 E. coli colonies isolated in Spain between 1986 and 1991 from piglets with diarrhoea, oedema disease and from healthy piglets, were determined. The serogroups determined in E. coli from diarrhoea were: O1, O2, O4, O5, O7, O8, O9, O12, O20, O21, O23, O25, O26, O32, O39, O45, O54, O75, O78, O80, O83, O91, O92, O101, O103, O113, O115, O116, O118, O125, O127, O138, O139, O141, O149, O153 and O157; from pigs with oedema disease: O8, O101, O138, O149 and O157; and from healthy piglets: O1, O2, O5, O7, O8, O9, O20, O21, O26, O29, O45, O64, O71, O80, O81, O91, O101, O105, O113, O115, O116, O126, O128, O132, O138, O139, O142, O146, O149, O152, O153, and O168. Serogroups O138, O141 and O149 were found to be statistically associated with enteric porcine colibacillosis (diarrhoea and oedema disease) (0.025 > P < 0.01). In addition, enterotoxigenic (ETEC) strains belonged to serogroups: O8, O9, O20, O101, O138, O141 and O149; verotoxigenic (VTEC) strains (VTEC) strains to serogroups 091 and 0138; and necrotizing (NTEC) strains to serogroups O2, O4, O8, O54, O78 and O83. Furthermore, 91.2% (249 out 273) of the ETEC (LT and/or STa) and/or VTEC strains belonged to only seven different serogroups. These major serogroups to which the ETEC and VTEC strains belonged, were determined in a lower percentage (21.2%) among non-toxigenic E. coli colonies isolated from sick and healthy piglets.

Animals↗

PubMed1996

Serogroups, toxins and antibiotic resistance of Escherichia coli strains isolated from diarrhoeic lambs in Spain.

One hundred and forty-four Escherichia coli strains isolated from 144 diarrhoeic lambs (5 to 21 days old) from 38 flocks in Spain were serotyped and investigated for production of enterotoxins (LT and STa), verotoxins (VT1 and VT2), cytotoxic necrotizing factors (CNF1 and CNF2), alpha-haemolysin (Hly) and enterohaemolysin (EntHly), for necrotic and lethal activities and for antibiotic resistance. The strains belonged to 39 different serogroups; however, 58% were of one of 13 serogroups (O4, O6, O7, O8, O9, O11, O23, O26, O77, O80, O101, O103 and O161) and only four of them (O8, O9, O11 and O77) accounted for 34% of strains. In total 10 (7%) toxigenic strains were detected: two LT+, two VT1+ EntHly+, four VT1+ EntHly-, one CNF1+ Hly+ and one CNF2+. The highest percentages of antibiotic resistance were reached in the group of antibiotics (tetracycline, streptomycin, sulphadiazine, ampicillin, kanamycin, neomycin, chloramphenicol, trimethoprim and cotrimoxazole) that are most generally used by Spanish veterinary clinics. We conclude that E. coli strains isolated from diarrhoeic lambs are not generally toxigenic and belong to a large number of serogroups.

Animals↗

PubMed1996

Prealbumin is the best nutritional predictor of survival in hemodialysis and peritoneal dialysis.

Patients undergoing dialytic therapy for end-stage renal disease (ESRD) have greater morbidity and mortality than age-matched individuals with similar demographics in the general population. Risk factors for early death during treatment for ESRD include advanced age, diabetes, hypertension, and malnutrition. We questioned whether the level of serum prealbumin at the start of uremia therapy might serve as a marker of subsequent survival in patients treated with maintenance hemodialysis (HD) and peritoneal dialysis (PD). Study cohorts included 111 HD and 78 PD patients followed for up to 5 years. Selected demographic characteristics and biochemical variables were tested for correlation with survival in each cohort. Variables evaluated included age, race, gender, diabetic status, and serum concentrations of albumin, creatinine, cholesterol, and prealbumin. For comparison, expected survival was calculated with Cox proportional hazards analysis, which accounts for confounding variables. We found that a higher relative risk (RR) of death in HD patients correlated with older age, the diagnosis of diabetes, and a serum prealbumin < 30 mg/dL. In PD patients, older age and the presence of diabetes correlated with a higher RR of death than in the standard population. When nutritional variables were analyzed separately, prealbumin < 30 mg/dL was the strongest variable that predicted mortality in HD patients (RR = 2.64, P = 0.002) and also predicted increased risk of mortality in PD patients (RR = 1.8, P = 0.035). Observed and expected survival was significantly higher in patients with enrollment prealbumin greater than 30 mg/dL in both HD and PD. The serum prealbumin level correlated significantly with other measures of nutrition, including serum albumin, serum creatinine, and serum cholesterol, in both HD and PD patients. Among tested markers of nutritional status, prealbumin level appears to be the single best nutritional predictor of survival in ESRD patients.

Cholesterol↗

PubMed1996

Serogroups, toxins and antibiotic resistance of Escherichia coli strains isolated form diarrhoeic goat kids in Spain.

Fifty-five Escherichia coli strains isolated from 55 diarrhoeic goat kids from 13 flocks in Spain were serotyped and investigated for production of enterotoxins (LT and STa), verotoxins (VT1 and VT2), cytotoxic necrotizing factors (CNF1 and CNF2), alpha-hemolysin (Hly) and enterohemolysin (EntHly), and for antibiotic resistance. Only 3 (5%) strains were toxigenic: 1 VT1+EntHly+ (serogroup O8) and 2 CNF2+ (both of serogroup O153). The strains serotyped belonged to 19 serogroups. However, 31 (56%) were of one nine serogroups (O3, O8, O9, O10, O11, O21, O44, O103 and O153) and only three of them (O8, O9 and O11) accounted for 29% of the strains. The highest percentages of antibiotic resistance in order of frequency were: streptomycin (93%), sulfadiazine (89%), tetracyline (84%), kanamycin (82%), neomycin (82%) and ampicillin (69%). We conclude that E. coli strains isolated from diarrhoeic goat kids are usually non-toxigenic and belong to a large number of serogroups.

Animals↗

PubMed1996

Partial least-squares regression for the quantitation of pharmaceutical dosages in control analyses.

A spectrophotometric method for the simultaneous determination of the active principle and a flavouring agent in syrups containing additional excipients is proposed. The calibration matrix must include all the variability expected in the samples and this is achieved using laboratory-made mixtures and production samples in order to ensure correct results. The optimum number of principal components for the regression model was selected by using various procedures. The proposed method was used to quantify samples from different production batches. The results are compared with those provided by HPLC.

Allylbenzene Derivatives↗