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Biomedical subjects

S Larsen

Publications and source records attributed to S Larsen.

At least 91 records · Page 5Linked to original sources
PubMed1999

Active back school: prophylactic management for low back pain. A randomized, controlled, 1-year follow-up study.

STUDY DESIGN: A randomized, controlled, single-center trial with a stratified group design. OBJECTIVE: To investigate the secondary prophylactic effect of the Active Back School program on minimizing recurrences of low back pain episodes. SUMMARY OF BACKGROUND DATA: The results of back school interventions are controversial. Previous work often used short intervention periods and low doses of practical training. However, studies with the highest methodologic scores have shown the best results, especially when conducted in occupational settings and coupled with a comprehensive rehabilitation program. METHODS: By block randomization, 19 men and 24 women were allocated to Active Back School, with 18 men and 20 women as control subjects. The Slumps test and number of low back pain episodes during the previous 36 months were used as stratification factors. There were no significant differences between the groups with regard to demographic factors and initially observed variables. Active Back School consisted of 20 lessons over a 13-week period. Each lesson was divided into a 20-minute theoretical part and a 40-minute exercise part. All participants were examined on enrollment, then 5 and 12 months after initiation of the program. Outcome measures were recurrence of low back pain episodes and number of days of sick leave. RESULTS: The recurrence of new low back pain episodes was significantly lower (P < 0.05) and the time from inclusion to the first new episode significantly longer (P < 0.01) in the Active Back School group than in the control group. In the Active Back School group, seven participants took sick leave because of low back pain episodes during the first 12 months of follow-up compared with 11 among the control subjects. The number of sick leave days was significantly lower (P < 0.05) in the Active Back School group than in the control group. CONCLUSION: Active Back School reduced the recurrence and severity of new low back pain episodes according to results of follow-up examinations performed 5 and 12 months after enrollment.

Adult↗
PubMed1999

Inhibition of human gastric lipase by intraduodenal fat involves glucagon-like peptide-1 and cholecystokinin.

Seven healthy volunteers were intubated with two double lumen nasogastric tubes, one in the stomach, the other in the duodenum. This system allows simultaneous sampling of gastric juice and separate intraduodenal perfusion with a dietary fat (fish oil, 1269 kJ). Gastrin-17 was infused i.v. at a rate of 40 pmol/kg/h throughout the study. Gastric lipase was measured at 15-min intervals as activity (tributyrin) and as immunoreactivity (ELISA). Infusion of gastrin-17 resulted in a stable increase in the plasma concentration from a basal concentration of 8.3 +/- 0.8 pmol/l to 41.4 +/- 4.2 pmol/l. Perfusion with fat reduced gastric lipase activity from 24.2 +/- 5.3 to 7.2 +/- 2.5 kU/l (P < 0.05), and immunoreactivity from 0.7 +/- 0.1 to 0.42 +/- 0.1 mg/l (P < 0.05). After termination of fat perfusion, gastric lipase secretion increased again, though not reaching preinhibitory concentrations. During the intraduodenal perfusion with fat the plasma concentrations of glucagon-like peptide-1 (GLP-1) and cholecystokinin (CCK) increased from 6.9 +/- 0.5 to 15.1 +/- 1.5 pmol/l (P < 0.05) and from 1.2 +/- 0.4 to 3.8 +/- 0.9 pmol/l (P < 0.05). This study reveals a negative effect of fat in the duodenum on gastric lipase secretion. This effect may be mediated by GLP-1 and/or CCK.

Adult↗
PubMed1999

Antipyrine, oxazepam, and indocyanine green clearance in patients with chronic pancreatitis and healthy subjects.

BACKGROUND: Hepatic drug metabolism was examined in patients with chronic pancreatitis and healthy controls by using a cocktail design with three different model compounds: antipyrine to express phase-I oxidation, oxazepam to express phase-II conjugation, and indocyanine green (ICG), a high-clearance compound. METHODS: Eight patients with chronic pancreatitis and seven healthy controls participated. Patients were diagnosed by the presence of typical morphologic changes of the pancreas on imaging and had a moderately but significantly reduced exocrine function and no or only slight impairment of the glucose tolerance. No one had a history or clinical signs of liver disease. Clearance of the three model compounds was estimated after the administration of 1 g antipyrine and 15 mg oxazepam orally and a bolus of indocyanine green, 0.5 mg/kg body weight, intravenously. RESULTS: The antipyrine clearance and ICG clearance were significantly decreased in the patients compared with the controls (mean, 27.2 ml/min; 95% confidence interval (CI), 19.4-35; versus 46.2 ml/min; 34.7-58.7, and 501 ml/min; 4014601, versus 771 mU/min; 677-865 (P < 0.05), respectively). The oxazepam clearance did not differ significantly between the two groups (181 ml/min (145-217) versus 178 ml/min (152-204)). The model drug clearance ratios between the patient and control clearances showed decreased values for antipyrine and ICG compared with the oxazepam data (0.59 and 0.65 versus 1.02, respectively). Patients and controls were characterized by a body weight of 58.2 kg (53.1-63.3) and 83.4 kg (72.7-94.1), respectively, and a body mass index (BMI) of 19.6 kg/m2 (17.9-21.3) versus 25.9 kg/m2 (23.4-28.4) (P < 0.05 for both). CONCLUSIONS: Patients with chronic pancreatitis characterized by a moderately reduced exocrine function and absence of diabetes mellitus and overt liver disease had a decreased antipyrine oxidation and ICG clearance, whereas no difference was seen in oxazepam conjugation when compared with healthy volunteers. In chronic pancreatitis the hepatic phase-I oxidation is reduced compared with the phase-II conjugation, as shown by the model drug clearance ratios. The clearance of ICG was also affected, pointing at a reduced hepatic plasma flow, provided that the hepatic extraction fraction is normal for these patients.

Adult↗
PubMed1999

The epidemiology and prognosis of glomerulonephritis in Denmark 1985-1997.

BACKGROUND: The existence of a national renal biopsy register and a national terminal uraemia status register in Denmark provides an opportunity to study the prognosis of glomerulonephritis (GN), and factors influencing prognosis. METHODS: Multivariate analysis of 2380 renal biopsies with GN performed between 1985 and 1997 was done to determine the influence of clinical and histological factors on prognosis. RESULTS: The incidence of GN (39/mo/year) and individual diagnoses did not change during the period. After 10 years, 32%, were dead, 13% terminally uraemic, 5%, uraemic and 50% well. Older age increased mortality, but not the incidence of renal failure after the first year. Male sex increased both mortality and incidence of renal failure (34 vs 24% at 10 years, P < 0.001). The diagnoses could be divided into three prognostic groups compared with the general population: a good prognostic group (minimal change GN and membranous GN ), with a relative mortality of three and a combined renal and patient mortality of four; a poor prognostic group [crescentic GN, HUS/TTP, chronic GN] with relative mortalities of 8-19 and 13-33, respectively; and the remainder with mortalities of 4-7 and 6-12. The presence of multiple glomerular pathology, chronic GN, nephrosclerosis and chronic interstitial nephropathy worsened the prognosis, while the presence of immune deposits only worsened the prognosis of focal segmental glomerulopathy. Mortality was related to uraemia and co-morbidity at biopsy, and to the incidence of renal failure. Renal failure was correlated to uraemia and hypertension at biopsy but not to nephrotic syndrome or atherosclerosis. All vascular complications were increased and were positively related to hypertension and negatively correlated to the incidence of uraemia. Crescentric glomerulonephritis combined with anti-GBM disease had a worse prognosis than Wegener's granulomatosis, with microscopic polyangiitis and pauci-immune disease occupying an intermediate position. The prognosis of mesangioproliferative GN was unaffected by the presence of IgA nephropathy and systemic lupus erythematosus.

Adolescent↗
PubMed1999

Crystallization and preliminary X-ray studies of beta-1, 4-galactanase from Aspergillus aculeatus.

Recombinant beta-1,4-galactanase from Aspergillus aculeatus has been crystallized and characterized by X-ray diffraction. Crystals were obtained in hanging drops by vapour-diffusion under the conditions 30% PEG 400, 0.2 M CaCl2 and 0.1 M Na HEPES buffered to pH 7.5. The crystals diffract to 2.3 A resolution and belong to one of the orthorhombic space groups I222 or I212121. The unit-cell dimensions are a = 60.42, b = 88.94 and c = 129.08 A. With one molecule in the asymmetric unit, the corresponding solvent content is approximately 48%.

Aspergillus↗
PubMed1999

Comparison of intra-articular injection of 2 ml of 0.9% NaCl solution with rest alone for treatment of horses with traumatic arthritis.

OBJECTIVE: To compare effects of intra-articular injection of 2 ml of 0.9% NaCl solution with rest alone for treatment of horses with traumatic arthritis. ANIMALS: 38 Standardbred horses with moderate to severe lameness that resulted from traumatic arthritis. PROCEDURE: Horses were stratified on the basis of number of affected joints. In each stratum, horses were allocated randomly to treatment groups (intraarticular injection of 2 ml of 0.9% NaCl solution vs rest only). Treatment was for a period of 3 weeks. Horses were inspected weekly with a final examination 2 to 4 weeks after completion of treatment. RESULTS: Mean lameness index was significantly lower during the 3-week treatment period and the entire study period for the NaCl-injected group. A significant decrease in the lameness index during the first 3-week treatment period also was detected for the rest-only group; however, the lameness index increased significantly for this group during the follow-up period, and an overall significant decrease was not detected. Comparison of the lameness index curve indicated a difference in favor of NaCl injection, with a significant difference between the 2 groups at final examination. Nine horses became sound during treatment with rest only, but 6 relapsed before final examination. In the NaCl-injected group, 5 of 10 sound horses relapsed. CONCLUSIONS AND CLINICAL RELEVANCE: Intra-articular injection of 2 ml of 0.9% NaCl solution was beneficial in horses with traumatic arthritis. Use of rest alone for a limited period was inadequate for treatment of young Standardbred horses with traumatic arthritis.

Animals↗
PubMed1998

Crystallization and preliminary X-ray diffraction studies of the heterogeneously glycosylated enzyme rhamnogalacturonan acetylesterase from Aspergillus aculeatus.

Well diffracting crystals of rhamnogalacturonan acetylesterase from Aspergillus aculeatus have been obtained in two polymorphic modifications despite its heterogeneous glycosylation. The best-diffracting crystals (resolution 1.55 A) are orthorhombic. The limit of the diffraction pattern of the other (trigonal) form is 2.5 A. The ability of the enzyme to crystallize appears to depend on the glycosylation of the protein sample. This aspect has been investigated by mass spectrometry, which also showed that the orthorhombic crystals have the same glycosylation as the protein sample used in the crystallization.

Acetylesterase↗
PubMed1998

The crystal structure of Lactococcus lactis dihydroorotate dehydrogenase A complexed with the enzyme reaction product throws light on its enzymatic function.

Dihydroorotate dehydrogenases (DHODs) catalyze the oxidation of (S)-dihydroorotate to orotate, the fourth step and only redox reaction in the de novo biosynthesis of pyrimidine nucleotides. A description is given of the crystal structure of Lactococcus lactis dihydroorotate dehydrogenase A (DHODA) complexed with the product of the enzyme reaction orotate. The structure of the complex to 2.0 A resolution has been compared with the structure of the native enzyme. The active site of DHODA is known to contain a water filled cavity buried beneath a highly conserved and flexible loop. In the complex the orotate displaces the water molecules from the active site and stacks above the DHODA flavin isoalloxazine ring, causing only small movements of the surrounding protein residues. The orotate is completely buried beneath the protein surface, and the orotate binding causes a significant reduction in the mobility of the active site loop. The orotate is bound by four conserved asparagine side chains (Asn 67, Asn 127, Asn 132, and Asn 193), the side chains of Lys 43 and Ser 194, and the main chain NH groups of Met 69, Gly 70, and Leu 71. Of these the Lys 43 side chain makes hydrogen bonds to both the flavin isoalloxazine ring and the carboxylate group of the orotate. Potential interactions with bound dihydroorotate are considered using the orotate complex as a basis for molecular modeling. The role of Cys 130 as the active site base is discussed, and the sequence conservation of the active site residues across the different families of DHODs is reviewed, along with implications for differences in substrate binding and in the catalytic mechanisms between these families.

Binding Sites↗
PubMed1998

A 'retro-inverso' PNA: structural implications for DNA and RNA binding.

'Retro-inverso' peptide nucleic acid (PNA) monomers of thymine (T*: N-(amidomethyl)-N-(N1-thyminyl-acetyl)-beta-alanyl) (and adenine) have been prepared and introduced in PNA oligomers. A homo 'retro-inverso' T*8 PNA was found not to hybridize to a complementary DNA or RNA oligonucleotide, whereas introduction of one retro-inverso thymine unit into the middle of a normal PNA 15-mer resulted in a c.a. 8 degrees C destabilization of the complex of this oligomer with a complementary DNA or RNA oligomer. In an effort to compensate for the structural nucleobase 'phase-shift' caused by the T* monomer by also introducing a beta-alanine monomer it is concluded that the effect of the T* backbone is -7 degrees C when hybridizing to DNA and -4.5 degrees C when hybridizing to RNA. Nonetheless, the T* unit shows good sequence discrimination comparable to that of normal PNA. Molecular dynamics simulations indicate an unfavourable conformation of the backbone amide carbonyl group resulting in reduced interaction with the aqueous medium and an 'electrostatic clash' with the carbonyl of the nucleobase linker. These results show that a simple inversion of an amide bond in the PNA backbone has a dramatic, and hardly predictable, effect on the DNA mimicking properties of the oligomer.

Crystallography, X-Ray↗
PubMed1998

Inhibition of human gastric lipase secretion by glucagon-like peptide-1.

Glucagon-like peptide-1 (GLP-1) may be one of the enterogastrone hormones of the ileal brake mechanism. We therefore studied its effects on gastric lipase secretion in healthy volunteers and vagotomized patients during infusion of pentagastrin. The intestinal incretin hormone GLP-1 (glucagon-like peptide-1, 7-36 amide) was investigated because of its inhibitory effects on gastric acid secretion and motility. GLP-1 infused intravenously in amounts corresponding to the postprandial release significantly inhibited pentagastrin-stimulated gastric lipase secretion and lipolytic activity. The inhibitory effect of GLP-1 persisted in vagotomized patients, suggesting that fundic chief cells, from which gastric lipase is released, or neighboring inhibitory cells could be equipped with GLP-1 receptors. Vagotomized patients had significantly higher plasma concentrations of gastrin and secretin. No significant changes of gastrin, secretin, and CCK secretion were seen during GLP-1 infusion in the vagotomized patients, whereas secretin decreased significantly in the healthy volunteers. GLP-1 seems to be a naturally occurring inhibitor of gastric lipase secretion acting via a nonvagal mechanism. Our results indicate that gastric lipase secretion is subject to hormonal stimulatory as well as inhibitory mechanisms.

Aged↗
PubMed1998

Development of play-the-winner design: weighting and accumulation of information.

BACKGROUND: Play-the-Winner (PTW) design was compared with Weighted-Play-the-Winner (WPW) design with regard to sensitivity to discriminate between treatments. METHODS: In total, 231 patients undergoing digestive surgery were included in a PTW study comparing safety of enoxaparin and dextran-70 in the prevention of venous thrombo-embolism. In the PTW model each patient was classified as a 'winner' or 'loser'. The treatment was changed when a patient was classified as 'loser', otherwise the same treatment was continued for the next patient. The study was performed by using a PTW design, but with all assessments needed for a WPW simulation. In the WPW design, a 'loser score' was calculated for each patient and summarized to a 'loser index' for consecutive patients given the same treatment. When this index exceeded a predefined value, treatment was changed and the 'loser index' set to zero. The WPW model with inheritance (WPWI) is identical to WPW, except that the overload of 'loser index' from the previous sequence with the same treatment was used as the starting value for the next. RESULTS: The PTW study revealed superiority of enoxaparin. This was enforced in the WPW model and further increased by WPWI. CONCLUSION: Changing from the PTW to WPW design and further to WPWI increased the sensitivity of the model, but at the same time the complexity of the design.

Adolescent↗
PubMed1998

The relationship between faecal bile acid profile with or without supplementation with calcium and antioxidants on recurrence and growth of colorectal polyps.

Faecal bile acids (FBA) have been implicated in colon carcinogenesis. The results of case-control studies of colorectal cancer and polyp patients are, however, conflicting. The aim of this study was to examine the influence of faecal bile acids on occurrence, growth and recurrence of colorectal polyps, and to see if a mixture of calcium and antioxidants might possibly act on cancer precursors through the effect on FBA. A total of 116 polyp-bearing patients were recruited from the outpatients department. Polyps < 10 mm in diameter were left in situ and measured by annual colonoscopy for 3 years. The patients received placebo or a mixture of antioxidants and calcium carbonate, 1.6 g calcium ion daily. Faecal samples were collected annually; the first, 1 month after start of intervention, freeze dried and subjected to bile acid profile analysis. Two age and sex matched control groups were recruited (n = 35), one from healthy volunteers (healthy controls) and one from the outpatients referred for colonoscopy, with no polyps (hospital controls). Twelve of 47 patients from the healthy volunteers had polyps (healthy polyp patients). One or more adenomas were found in 93 patients. The faeces of the hospital controls had significantly higher concentrations of total and secondary bile acids than did the healthy controls. There was no difference in FBA profile between the polyp group and the hospital controls, but significantly higher concentration of total and secondary faecal bile acids in the healthy polyp patients compared with the healthy control group (P < 0.05). No increased concentration of FBA were found in the polyp patients with multiple polyps (n = 21) or previous treatment for colorectal cancer (n = 7). No associations between FBA profile and growth or recurrence of colorectal polyps were found. The polyp patients receiving active medication had higher faecal concentrations of total and secondary bile acids in the beginning of the study than at the end, in spite of a good compliance. The present study does not support bile acids as being important markers of initiation or growth of small and medium sized colorectal adenomas. In the present study the calcium and antioxidants did not seem to affect the growth or recurrence of colorectal adenomas by increased TBA excretion in the faeces.

Antioxidants↗
PubMed1998

Potentially avoidable perinatal deaths in Denmark, Sweden and Lithuania as classified by the Nordic-Baltic classification.

OBJECTIVES: To analyse which subgroups of perinatal deaths contribute most to the perinatal mortality rate in Lithuania compared with Denmark/Sweden. DESIGN: Comparison of all perinatal deaths in Denmark/Sweden 1991 and Lithuania 1993-1994 by the common Nordic-Baltic perinatal death classification, based on information from the medical records. RESULTS: The doubled perinatal mortality in Lithuania compared with Denmark/Sweden is mainly explained by a threefold increase of intrapartum and two- to fivefold increase in neonatal deaths of nonmalformed infants. The higher rate of malformed infants is partly explained by a four times higher mortality from neural tube defects. CONCLUSIONS: The use of a common perinatal death classification has identified categories mainly responsible for the higher rate of perinatal mortality, but further investigation of potentially avoidable factors requires further study.

Adult↗
PubMed1998

Effect of sham feeding and acute suppression of acid secretion on human gastric lipase secretion.

OBJECTIVE: Gastric lipase and gastric acid are secreted simultaneously. The aim of this study was to investigate whether the acid interferes with the lipase secretion. The secretion of human gastric lipase was studied during blockade of gastric acid secretion and modified sham feeding to estimate the impact of these conditions on both gastric lipase enzyme activity and immunoreactivity. METHODS: Eight healthy volunteers were intubated with a nasogastric tube. We examined gastric aspirates for the amount and activity of lipase secretion during basal conditions, after blockade of acid secretion with a proton pump inhibitor (omeprazole iv. infusion), and in response to sham feeding (chewing gum) during the blockade. RESULTS: The amount of secreted gastric lipase was unaffected by blockade of acid secretion and increased significantly after sham feeding (169.9+/-35.7 microg/15 min to 348.1+/-79.2 microg/15 min; p < 0.01). Likewise, the output of enzyme activity increased after sham feeding (0.63+/-0.09 kU/15 min to 1.52+/-0.36 kU/15 min; p < 0.03). The concentration of enzyme activity remained unchanged by blockade of acid secretion, whereas the output of enzyme activity was decreased, probably because of reduced volume secretion or denaturation and conformational changes of the enzyme. Plasma concentrations of gastrin increased in response to blockade of acid secretion (basal 9.6+/-1.4 pmol/L to 13.3+/-2.9 pmol/L; p < 0.02). CONCLUSIONS: Gastric acid secretion is not a prerequisite for gastric lipase secretion. Lipase enzyme activity, though, is sensitive to anacidic conditions.

Adult↗
PubMed1998

Growth and recurrence of colorectal polyps: a double-blind 3-year intervention with calcium and antioxidants.

BACKGROUND: Dietary calcium and antioxidants have been suggested as protective agents against colorectal cancer. This has been supported by animal experimental studies, case control and cohort studies. MATERIALS AND METHODS: In a prospective intervention study of colorectal adenomas, and intermediary stage in colorectal carcinogenesis, 116 polyp-bearing patients received a placebo-controlled daily mixture of beta-carotene 15 mg, vitamin C 150 mg, vitamin E 75 mg, selenium 101 microg, and calcium (1.6 g daily) as carbonate for a period of 3 years with annual colonoscopic follow-up to test if the mixture was able to reduce polyp growth or recurrence. All polyps of < 10 mm at enrollment or follow-up were left unresected until the end of the study. RESULTS: 87-91% of the patients attended the annual endoscopic follow-up investigations, and 19% of the patients dropped out of the medical intervention. The rest consumed 85% of the total amount of tablets over the 3 years. The fecal calcium concentration was 2.3-2.7 times higher in patients taking active medication compared to the placebo group. Diet registration showed that, when adding the intake of antioxidants and calcium from diet and intervention, there was a significant difference between the intake of these substances in the active and the placebo group. No difference was detected in the growth of adenomas between the active and the placebo group from year to year and for the total study period. Moreover, there was no effect on polyps of < 5 or 5-9 mm, or on polyps in the different colonic segments analyzed separately. A reduced growth of adenomas was found in patients <60 years of age taking active medication (n = 8) compared to those taking placebo (n = 6; mean difference 2.3 mm; 95% CI 0.26-4.36). There was a significantly lower number of patients free of new adenomas in the placebo group compared to those taking active medication as tested by logistic regression and Kaplan-Meier analysis (log-rank test p value 0.035). Subgroup analysis showed that only the group of patients with no family history of colorectal cancer, those with only one adenoma at inclusion, and those <65 years benefitted from the intervention medication. CONCLUSION: The study did not find an overall effect on polyp growth. Our data, however, may support a protective role of calcium and antioxidants on new adenoma formation.

Adenoma↗
PubMed1998

Do combinations of 1 mg estradiol and low doses of NETA effectively control menopausal symptoms?

OBJECTIVES: This study compared two continuous-combined hormone replacement therapy (HRT) formulations, 1 mg estradiol (E2)/0.25 mg norethisterone acetate (NETA) and 1 mg E2/0.5 mg NETA, with placebo, with regard to the efficacy for vasomotor symptom relief in menopausal women. METHODS: A total of 119 women aged 45-61 years with moderate and severe hot flushes and with amenorrhea for at least 3 months were randomly assigned to 12 weeks' treatment with 1 mg E2/0.25 mg NETA, 1 mg E2/0.5 mg NETA or placebo. The number and severity of hot flushes, as well as any vaginal bleeding, were recorded on a daily basis. The Kupperman Menopausal Index, Greene Climacteric Scale and visual analog scales for various symptoms were assessed before and after treatment. Subpopulation analysis according to menopausal status was performed. RESULTS: Both combinations significantly reduced the number and severity of hot flushes, compared to placebo. A reduction of approximately 85% in vasomotor symptomatology occurred in the two combination groups by week 4 of treatment, and this was further diminished throughout the study to approximately 97% reduction by week 12. At the end of the study, 85% of the women receiving 1 mg E2/0.5 mg NETA and 71% of the women receiving 1 mg E2/0.25 mg NETA were considered to the clinically adequate responders to treatment. Both combinations were associated with significant improvements, compared to placebo, in visual analog scales for overall general condition, Kupperman Menopausal Index, and Greene Climacteric vasomotor and psychological subscales. While both combinations resulted in similar bleeding profiles in postmenopausal women, the combination of 1 mg E2/0.5 mg NETA resulted in the lowest incidence of bleeding in late perimenopausal women. CONCLUSIONS: The combinations of 1 mg E2/0.25 mg NETA and 1 mg E2/0.5 mg NETA rapidly relieve vasomotor symptoms and are efficacious in the majority of menopausal women, including those with severe hot flushes.

Estradiol↗
PubMed1998

An analysis of the value of some antigen-antibody interactions used as diagnostic indicators in a treponemal Western blot (TWB) test for syphilis.

Densiometric quantitation and spreadsheet normalization were used to refine the parameters defining a treponemal Western blot (TWB) test for syphilis. Initially using 84 defined reactive and 105 defined non-reactive sera, we determined that the immune response to the 17 kDa antigen was the most critical of the following three candidate test determinants: the 47 kDa, 17 kDa and 15.5 kDa bands. In a second study using 124 cases of clinically diagnosed syphilis and 354 "normal" donors, a diluted serum sample was included as a minimal reactive control for the 17-kDa immune response. Reactivity to all three test determinants was obligatory for a test result to be interpreted as positive. Of the 124 cases of syphilis, 7 were nonreactive by TWB (sensitivity = 94%); of the 354 normal donors, 7 tested reactive (specificity = 98%). Forty (11%) normal serum samples had detectable but less than minimal reactivity to the 17 kDa band. Frequencies of immune response to a larger group of 12 antigens were tallied for the 124 clinically diagnosed cases of syphilis and an equal subset (124) of the normal group. In the normal subset, 72% and 52% of the samples had detectable reactivity to the 47 and 15.5 kDa antigens, respectively, while 10%, 5% and 3% reacted with the 17, 24 and 44.5 kDa antigens, respectively. Follow-up TWB testing of the clinically diagnosed cases revealed that previously untreated patients with primary or secondary syphilis were more likely to a show decrease in TWB reactivity than patients with latent symptoms who had been treated previously. As a diagnostic indicator of syphilis, the 17-kDa antigen was found to have the best combined attributes of sensitivity and specificity. Although, the highly specific 44.5 kDal and 24 kDal bands were often redundant as diagnostic indicators they are useful for the interpretation of borderline results. In addition, absence of the highly sensitive 47 and 15.5 kDa indicators should be useful in resolving some problem diagnoses.

Antibodies, Bacterial↗