TLIF Online Videos for Patient Education-Evaluation of Comprehensiveness, Quality, and Reliability

Over the last few decades, the number of lumbar interbody fusion surgeries performed has been constantly increasing, with transforaminal lumbar interbody fusion (TLIF) being one of the most common surgical techniques. Due to easy accessibility, patients frequently use YouTube to obtain information on health-related issues. Consequently, online video platforms may be a valuable tool for patient education. The aim of this study was to assess the quality, reliability, and comprehensiveness of online videos on TLIF. We screened 180 videos on YouTube, yielding a total of 30 videos that met the inclusion criteria. These videos were evaluated using Global Quality Scale, DISCERN reliability tool, and JAMA Benchmark Score, and assessed in regard to their comprehensiveness and coverage of relevant aspects. At the time of rating, the videos had between 9188 and 1,530,408 views and between 0 and 3344 likes. The median rater assessment for all videos was "moderate quality". GQS and subjective grades showed a moderate to strong statistically significant association with views and likes. Considering this association of GQS and subjective grade with views and likes, these criteria could be used by laypersons to identify good-quality content. Nevertheless, there is an urgent need for peer-reviewed content that covers all of the relevant aspects.

Sports in LCHAD Deficiency: Maximal Incremental and Endurance Exercise Tests in a 13-Year-Old Patient with Long-Chain 3-Hydroxy Acyl-CoA Dehydrogenase Deficiency (LCHADD) and Heptanoate Treatment

Exercise and subsequent catabolism is a potential trigger for creatine kinase (CK) concentration increase (rhabdomyolysis) in patients with LCHADD, therefore we evaluated the clinical and biochemical stability under physical exertion conditions at the age of 13 years in a currently 14-year-old LCHADD patient treated with heptanoate.LCHADD was diagnosed during first decompensation at age 20 months. In the following 2 years, the patient had several episodes of rhabdomyolysis. Heptanoate 0.5-1 g/kg/day was started at 4 years, with no further CK elevations since. He is clinically stable, has retinopathy without vision impairment or polyneuropathy. Maximal incremental and endurance exercise tests were performed to evaluate both clinical and metabolic stability during and after exertion.Physical fitness was adequate for age (maximum blood lactate 7.0 mmol/L, appropriate lactate performance curve, maximum heart rate of 196 bpm, maximum power 139 Watt = 2.68 Watt/kg body weight). There were no signs of clinical (muscle pain, dark urine) or metabolic derangement (stable CK, acyl carnitine profiles, blood gas analyses) - neither after maximal incremental nor endurance exertion.This case illustrates that both under maximal incremental and endurance exertion, clinical and biochemical parameters remained stable in this currently 14-year-old LCHADD patient receiving heptanoate treatment.

Imaging of acute stroke prior to treatment: current practice and evolving techniques

Standard imaging in acute stroke is undertaken with the aim of diagnosing the underlying cause and excluding stroke mimics. In the presence of ischaemic stroke, imaging is also needed to assess patient suitability for treatment with intravenous thrombolysis. Non-contrast CT is predominantly used, but MRI can also exclude any contraindications to thrombolysis treatment. Advanced stroke imaging such as CT and MR angiography and perfusion imaging are increasingly used in an acute setting. In this review, we discuss the evidence for the application of these advanced techniques in the imaging of acute stroke.

Human osteosarcoma cells respond to sorafenib chemotherapy by downregulation of the tumor progression factors S100A4, CXCR4 and the oncogene FOS

Osteosarcoma is a rare but aggressive bone neoplasm in humans, which is commonly treated with surgery, classical chemotherapy and radiation. Sorafenib, an inhibitor of a number of kinases targeting the Raf/MEK/ERK pathway, is a promising new chemotherapeutic agent in human medicine that has been approved since 2006 for the therapy of renal cell carcinoma and since 2007 for the treatment of hepatocellular carcinoma. Here, we studied the antimetastatic potential of 4 µM of this multikinase inhibitor in a human osteosarcoma cell line. DNA microarray-based gene expression profiling detected 297 and 232 genes upregulated or downregulated at a threshold of >2-fold expression alteration (P<0.05) in the sorafenib-treated cells. Three genes (CXCR4, FOS and S100A4) that are involved in tumor progression were chosen for validation by quantitative PCR (qPCR) and protein expression analysis. The decrease in RNA expression detected by microarray profiling was confirmed by qPCR for all three genes (P<0.01). On the protein level, sorafenib-induced reduction of S100A4 was verified both by western blotting and immunohistochemistry. For CXCR4 and c-Fos, a reduced protein expression was shown by immunohistochemistry, for c-Fos also by immunoblotting. We conclude that sorafenib could serve as a potent chemotherapeutical agent by which to inhibit the metastatic progression of osteosarcomas.

Catechol conjugates are in vivo metabolites of Salicis cortex

After oral administration of 100 mg/kg b. w. (235.8 µmol/kg) salicortin to Wistar rats, peak serum concentrations of 1.43 mg/L (13.0 µM) catechol were detected after 0.5 h in addition to salicylic acid by HPLC-DAD after serum processing with β-glucuronidase and sulphatase. Both metabolites could also be detected in the serum of healthy volunteers following oral administration of a willow bark extract (Salicis cortex, Salix spec., Salicaceae) corresponding to 240 mg of salicin after processing with both enzymes. In humans, the cmax (1.46 mg/L, 13.3 µM) of catechol was reached after 1.2 h. The predominant phase-II metabolite in humans and rats was catechol sulphate, determined by HPLC analysis of serum samples processed with only one kind of enzyme. Without serum processing with glucuronidase and sulphatase, no unconjugated catechol could be detected in human and animal serum samples. As catechol is described as an anti-inflammatory compound, these results may contribute to the elucidation of the mechanism of the action of willow bark extract.

Isothermal loop-mediated amplification (LAMP) for diagnosis of contagious bovine pleuro-pneumonia

Background

Contagious Bovine Pleuropneumonia (CBPP) is the most important chronic pulmonary disease of cattle on the African continent causing severe economic losses. The disease, caused by infection with Mycoplasma mycoides subsp. mycoides is transmitted by animal contact and develops slowly into a chronic form preventing an early clinical diagnosis. Because available vaccines confer a low protection rate and short-lived immunity, the rapid diagnosis of infected animals combined with traditional curbing measures is seen as the best way to control the disease. While traditional labour-intensive bacteriological methods for the detection of M. mycoides subsp. mycoides have been replaced by molecular genetic techniques in the last two decades, these latter approaches require well-equipped laboratories and specialized personnel for the diagnosis. This is a handicap in areas where CBPP is endemic and early diagnosis is essential.

Results

We present a rapid, sensitive and specific diagnostic tool for M. mycoides subsp. mycoides detection based on isothermal loop-mediated amplification (LAMP) that is applicable to field conditions. The primer set developed is highly specific and sensitive enough to diagnose clinical cases without prior cultivation of the organism. The LAMP assay detects M. mycoides subsp. mycoides DNA directly from crude samples of pulmonary/pleural fluids and serum/plasma within an hour using a simple dilution protocol. A photometric detection of LAMP products allows the real-time visualisation of the amplification curve and the application of a melting curve/re-association analysis presents a means of quality assurance based on the predetermined strand-inherent temperature profile supporting the diagnosis.

Conclusion

The CBPP LAMP developed in a robust kit format can be run on a battery-driven mobile device to rapidly detect M. mycoides subsp. mycoides infections from clinical or post mortem samples. The stringent innate quality control allows a conclusive on-site diagnosis of CBPP such as during farm or slaughter house inspections.

Computed tomographic emphysema distribution: relationship to clinical features in a cohort of smokers

Computed tomography (CT) scanning allows precise assessment of both the extent and distribution of emphysema. There has been little work on the relationship between the distribution of emphysema and clinical features of the disease. The current study investigated the association between clinical features and distribution of emphysema. A total of 129 patients with smoking-related chronic obstructive pulmonary disease underwent CT assessment of the extent and distribution of their emphysema (core/rind and upper/lower zone predominance). Emphysema was found predominantly in the upper/core zone and this distribution was related to the extent of disease. Core predominance was associated with lower forced expiratory volume in one second (FEV(1)), FEV(1)/forced vital capacity ratio and body mass index (BMI); and with higher BODE (BMI, airflow obstruction, dyspnoea and exercise capacity) index and Medical Research Council dyspnoea score. Upper-zone predominance was associated with female sex and an increased total St George's Respiratory Questionnaire score. Using multiple linear regression age, sex and whole lung emphysema severity were independently associated with core/rind distribution, while sex and whole lung emphysema severity were independently related to upper/lower distribution. Distribution of emphysema related best to clinical features when divided into core/rind predominance. However, the effects were not independent of the extent of emphysema. Increased age and female sex were related to disease distribution independent of emphysema severity. These findings may be related to differences in development of emphysema.

The role of radiotherapy in treating small early invasive breast cancer

AIM

The aim of the study was to identify if radiotherapy can be safely avoided in a selected subgroup of largely screening detected small invasive breast cancer.

METHODS

One hundred and eighty-eight patients with node negative invasive early breast cancer < or =1cm (< or =T1b) treated in our centre between 1990 and 2004 were retrospectively followed for local, regional and distant recurrences. Treatment involved adequate local excision by breast conserving surgery (BCS). Axillary staging was performed by a four node axillary sampling until 2000, following which sentinel lymph node sampling was employed. All sections were assessed histologically by haematoxylin and eosin stained sections. The inked margins were reported as being involved, close and clear. Radiotherapy (RT) was employed only if the resected margins were inadequate, and in those with involved axillary nodes who refused further completion axillary clearance.

RESULTS

Ninety-four patients (Group A) had BCS alone and 79 patients (Group B) had both BCS and RT. There was no ipsilateral breast tumour recurrence (IBTR) in 88 patients in Group A, corresponding to an actuarial freedom from IBTR of 96%, 91% and 88.1% at 5 years, 8 years and 9 years. In Group B, there was no IBTR in 75 patients corresponding to an actuarial freedom from IBTR of 97%, 94.9% and 90.6% at 5 years, 8 years and 10 years.

CONCLUSION

Our experience over 14 years has shown that it is possible to safely avoid radiotherapy in a selected subgroup of small invasive breast cancer.

Cicloral versus neoral: A bioequivalence study in healthy volunteers on the influence of a fat-rich meal on the bioavailability of cicloral

The bioavailability of cyclosporine a (CyA) was assessed in 2 cross-over studies with 12 healthy male volunteers each. Study A compared the bioavailability of Cicloral (test) with the microemulsion Neoral (reference) in the fasting state. Study B examined the influence of a fat-rich meal composed according to the Food and Drug Administration (FDA) recommendations on the bioavailability of Cicloral. Each volunteer received a single dose of 200 mg CyA in each period. Whole blood CyA concentrations were determined using HPLC up to 48 hours after drug administration. The pharmacokinetic parameters were determined using standard noncompartmental methods. The mean bioavailability of Cicloral compared with Neoral amounted to 83% (AUC) and 78% (Cmax), respectively. When administered after a fat-rich meal, the bioavailability of Cicloral was 121% (AUC) and 132% (Cmax) compared with fasting administration. Time to Cmax was 1.3 to 1.4 hours for both medications and modes of administration. Bioequivalence could not be proven either between Cicloral and Neoral, or between Cicloral fasting versus after a fat-rich meal. We conclude that the lower bioavailability and the influence of food on the bioavailability of Cicloral must be taken into account when switching from Neoral to the generic formulation.

Bioavailability of opipramol from a film-coated tablet, a sugar-coated tablet and an aqueous solution in healthy volunteers

Opipramol (4-[3-(5H-dibenz[b,f]-azepine-5-yl)-propyl]-1-piperazine-ethanol dihydrochloride, CAS 315-72-0) is regarded as an anxiolytic compound with antidepressant properties, and it is one of the most frequently prescribed psychotropic drugs in Germany. In two open, randomized cross-over studies in 20 (study 1) and 18 (study II) healthy volunteers, the relative bioavailability of 50 mg opipramol-2HCl from a sugar-coated tablet was compared with an aqueous solution, and of 100 mg opipramol-2HCl from a newly developed film-coated tablet was compared with the sugar-coated tablet. The concentrations of opipramol were determined in plasma by high-performance liquid chromatography (HPLC) with photometric detection. The mean dose corrected kinetic parameters of opipramol were similar after administration of all formulations. The peak concentrations of opipramol were 13-15 ng ml-1 (study I) and 28 ng ml-1 (study II). They were achieved after 3 h. The area under the plasma concentration-time curve was about 170 ng ml-1 h (study I) and about 320 ng ml-1 h (study II). The terminal plasma half-life was 11 h. Bioequivalence was proven between sugar-coated tablet and aqueous solution, and between film-coated tablet and sugar-coated tablet, respectively. In addition, in study II the plasma concentrations and pharmacokinetic parameters of the metabolites opipramol N-oxide and deshydroxyethyl opipramol were determined.

The relationship between birth weight and maternal glycated haemoglobin (HbA1c) concentration in pregnancies complicated by Type 1 diabetes

AIM

To examine the relationships between maternal HbA1c concentration at different time points and birth weight in pregnancies complicated by pre-existing Type 1 diabetes.

METHODS

A comprehensive audit dataset was collected prospectively on all deliveries in Scotland to women with pre-existing Type 1 diabetes occurring between 1 April 1998 and 31 March 1999. Data items included HbA1c concentrations prior to conception and in each of the three trimesters of pregnancy, and birth weight. Relationships between standardized birth weight and HbA1c concentrations at each of the four time points were examined using correlation analysis.

RESULTS

Standardized birth weight (Z scores) could be calculated for 203 of 208 singleton liveborn infants. HbA1c concentrations, standardized to correct for assay differences among hospitals, at different time points were available for between 134 (pre-pregnancy) and 192 (third trimester) cases. Standardized birth weight, relative to a reference population, showed a unimodal distribution, shifted to the right (mean, +1.57 sd). There was a significant negative correlation between pre-pregnancy HbA1c and birth weight (Spearman's R, -0.208; P = 0.016). There were no statistically significant correlations for other time points.

CONCLUSIONS

Standardized birth weight scores of the infants of diabetic mothers are higher than those of a reference population. There is no simple relationship between maternal glycaemic status and birth weight, but there appears to be a paradoxical inverse relationship between pre-pregnancy glycaemic control and standardized birth weight.

Is radiotherapy needed after breast conservation for small invasive breast cancers?

AIMS

The purpose of this study was to determine the rate of local recurrence in patients with small invasive breast cancers (<1 cm) who had been treated with breast-conserving surgery either with (group 1) or without (group 2) adjuvant radiotherapy.

METHODS

This is a retrospective study of 110 patients with an invasive breast cancer less than 1 cm in size, treated in our centre by breast-conserving surgery. Parameters examined included age at and mode of presentation, histopathological features, adjuvant therapy, length of follow-up and outcome in terms of local recurrence rate and death.

RESULTS

In group 1 there were 59 women of median age 57 (38-80) years. The median tumour size was 9 (1-10) mm and median follow-up was 74 (15-110) months. There were no local recurrences. In group 2 the median age at presentation was 59 (48-81) years. The median tumour size was 7 (2-10) mm and median follow-up was 47 (14-93) months. There were three non-breast-cancer related deaths and three local recurrences (6%).

CONCLUSIONS

A local recurrence rate of 6% at almost 4 years median follow-up suggests that it may be possible to avoid adjuvant radiotherapy in a subgroup of largely screen-detected, node-negative patients with invasive tumours less than 1 cm, in whom adequate local excision is performed. Further follow-up is required to substantiate this.

Phase 1/2 study of synchronous methotrexate, cisplatin, vincristine (MOPq10) chemotherapy and radiation for patients with locally advanced bladder cancer

PURPOSE

This phase 1/2 study was designed to test toxicity and effectiveness of combination chemotherapy and concurrent radiotherapy in the treatment of invasive bladder cancer.

METHODS AND MATERIALS

17 patients with localised muscle-invasive bladder cancer, clinical stages T2-3 N0, M0, were treated with a radiotherapy schedule of 55 Gy in 20 fractions over 4 weeks restricted to the bladder and 3 cycles of concurrent dose-intensive combination chemotherapy consisting of cisplatin 60 mg/m(2), vincristine 2 mg and methotrexate 60 mg/m(2) at 10-day intervals (MOPq10).

RESULTS

The complete remission rate following MOPq10 chemotherapy and radiotherapy was 88% as assessed at first cystoscopy with 82% remaining disease-free at 1 year. Risk factor analysis shows those older than 63 years (median) and those with creatinine clearance equal or less than the mean did worse. Actuarial disease-free survival at 2 years was 68% and of the patients treated 4/17 experienced acute G3/4 toxicity.

CONCLUSION

This combination regimen was feasible. Its high initial response rate justifies further exploration in a randomised phase 2/3 trial setting with bladder volume and quality of life assessment.

Effect of roxithromycin on the pharmacokinetics of lovastatin in volunteers

OBJECTIVE

To investigate the influence of concomitant administration of roxithromycin on the plasma pharmacokinetics of lovastatin.

METHODS

In an open, randomized, crossover study, 12 healthy volunteers received 80 mg lovastatin orally either alone or concomitantly with 300 mg roxithromycin after 5-day pretreatment with roxithromycin 300 mg daily. Plasma concentrations of lovastatin (lactone and acid) were determined using high-performance liquid chromatography, and the pharmacokinetic parameters were estimated.

RESULTS

The mean (+/- SD) pharmacokinetic parameters of lovastatin lactone with and without roxithromycin were maximum concentration (Cmax) 8.49+/-6.80/16.3+/-9.4 ng ml(-1), time to Cmax (tmax) 1.8+/-0.4/1.7+/-0.6 h, terminal plasma half-life (t1/2) 4.3+/-2.0/3.7+/-2.5 h, area under the plasma concentration-time curve from zero to infinity (AUC0-infinity) 53+/-60/85+/-67 ng ml(-1) h. The respective parameters of lovastatin acid were Cmax 24.6+/-13.4/17.8+/-11.0 ng ml(-1), tmax 3.7+/-1.1/4.1+/-0.7 h, t1/2 3.2+/-2.5/4.3+/-2.8 h, AUC0-infinity 149+/-123/105+/-58 ng ml(-1) h. Mean bioavailability of lovastatin lactone was lower and that of lovastatin acid was higher with concomitant treatment. However, the differences were significant only with respect to lovastatin lactone (AUC and Cmax) and Cmax of lovastatin acid.

CONCLUSION

Roxithromycin does not influence the pharmacokinetics of lovastatin in such a way that dosage adjustment of lovastatin seems to be necessary during co-administration.

Pharmacokinetics of therapeutic doses of tropisetron in healthy volunteers

AIMS

To establish the bioavailability of tropisetron (5 mg) administered orally as capsule compared with 2 mg given intravenously.

METHODS

Using a randomized crossover design, 18 healthy volunteers received a single oral dose of tropisetron (5 mg) and an intravenous bolus of tropisetron (2 mg) separated by a wash-out period of 1 week. Plasma concentrations of tropisetron were determined by h.p.l.c. and the pharmacokinetic parameters were estimated.

RESULTS

The mean pharmacokinetic parameters for 5 mg tropisetron given orally were Cmax 3.46 ng ml(-1), t(max) 2.6 h, t(1/2) 5.7 h and AUC(0,infinity) 32.9 ng ml(-1) h. After intravenous administration initial plasma concentration was 15.1 ng ml(-1), t(1/2) 5.6 h, AUC(0,infinity) 20.7 ng ml(-1) h, V 678 l and CL 1800 ml min(-1). An inverse correlation was demonstrated between CYP2D6 activity, measured by the sparteine metabolic ratio, and the bioavailability (mean 0.60, range 0.27-0.99) of oral tropisetron.

CONCLUSIONS

Tropisetron exhibits a wide range of oral bioavailability at therapeutic doses, which is mainly determined by CYP2D6 activity.

Determination of opipramol in human plasma by high-performance liquid chromatography with photometric detection using a cyanopropyl column

A high-performance liquid chromatographic method is described for the determination of opipramol in human plasma. Opipramol was extracted into tert.-butylmethyl ether, separated on a cyanopropyl silica column and detected at 254 nm. Imipramine was used as internal standard. The limit of quantitation was 250 pg/ml using 1.5 ml plasma. Precision was better than 9%, inaccuracy less than 8%. The assay is more sensitive than previously published methods, and it has been applied to the analysis of plasma samples from a pharmacokinetic study.

Cotranscriptional cap 4 formation on the Trypanosoma brucei spliced leader RNA

mRNA cap formation in trypanosomatid protozoa is mediated through trans-splicing of the capped spliced leader (SL) sequence of the SL RNA onto the 5' end of all mRNAs. The SL RNA cap structure in Trypanosoma brucei is unique among eukaryotes and consists of 7-methylguanosine (m(7)G) followed by four methylated nucleotides (cap 4): m(7)Gpppm(2)(6)AmpAmpCmpm(3)Um. Using transcriptional arrest in permeable T. brucei cells, we have analyzed the temporal progression of cap 4 formation on the 140-nucleotide-long SL RNA. m(7)G capping of the SL RNA could be detected on prematurely terminated SL RNA transcripts of 56 nucleotides in length and longer. Subsequent modifications characteristic of the SL RNA cap 4 were added successively in a 5' to 3' direction and appeared to be independent of core ribonucleoprotein formation. Transcripts between 56 and 67 nucleotides in length were partially modified and carried methyl groups on the first two adenosine residues, whereas a fully modified cap 4 structure was present on transcripts arrested at position 117 and beyond. Taken together, our results are consistent with a cotranscriptional mechanism for generating the cap 4 structure on the SL RNA.

A new twist in trypanosome RNA metabolism: cis-splicing of pre-mRNA

It has been known for almost a decade and a half that in trypanosomes all mRNAs are trans-spliced by addition to the 5' end of the spliced leader (SL) sequence. During the same time period the conviction developed that classical cis-splicing introns are not present in the trypanosome genome and that the trypanosome gene arrangement is highly compact with small intergenic regions separating one gene from the next. We have now discovered that these tenets are no longer true. Poly(A) polymerase (PAP) genes in Trypanosoma brucei and Trypanosoma cruzi are split by intervening sequences of 653 and 302 nt, respectively. The intervening sequences occur at identical positions in both organisms and obey the GT/AG rule of cis-splicing introns. PAP mRNAs are trans-spliced at the very 5' end as well as internally at the 3' splice site of the intervening sequence. Interestingly, 11 nucleotide positions past the actual 5' splice site are conserved between the T. bruceiand T. cruzi introns. Point mutations in these conserved positions, as well as in the AG dinucleotide of the 3' splice site, abolish intron removal in vivo. Our results, together with the recent discovery of cis-splicing introns in Euglena gracilis, suggest that both trans- and cis-splicing are ancient acquisitions of the eukaryotic cell.

Endoscopic management of inoperable cholangiocarcinoma using iridium-192

We report a well tolerated endoscopic technique of administering intraluminal radiotherapy to 14 patients with inoperable cholangiocarcinoma, in which the iridium-192 wire source was inserted down a nasobiliary catheter placed within a previously inserted endoscopic biliary prosthesis, thus allowing bile flow to continue during treatment. Radiotherapy was commenced 2 weeks after biliary decompression, when the median serum bilirubin level had fallen from 213 to 34 mumol/l. A total radiation dose of 6000 cGy at 0.5 cm from the source was administered over a median of 85 h (range 77-116 h). In four patients there was a transient increase in serum bilirubin during iridium treatment and, in two cases (14 per cent), this was associated with mild cholangitis. Both cases resolved rapidly once the iridium wire and nasobiliary catheter were removed. The median hospital stay after treatment was 2.5 days (range 0-28 days). The late complications associated with stent blockage were minimized by routinely changing stents at 4-6 monthly intervals; ten of the patients have so far undergone from one to five (median three) stent changes. Five patients have died at 3.6-8.2 months (median 4.8 months) following iridium treatment; four had extensive type III hilar lesions at diagnosis. Nine patients are still alive at 5.4-31.0 months (median 16.4 months). The overall median survival after iridium therapy is 10.5 months. This technique of endoscopic biliary decompression before internal iridium administration minimizes complications by allowing biliary drainage during treatment. The role of this treatment in patients with inoperable cholangiocarcinoma awaits the results of randomized, controlled trials.

"Please reply impersonally": communication outside a rural practice

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The primary structure of porcine glandular kallikreins

The amino acid sequence of the A- and B-chains of porcine pancreatic kallikrein B is presented and compared to that of porcine trypsin. The overall homology between both enzymes is 37% identical residues in corresponding position and 51% chemically similar resideus. Comparison of the sequences with the crystal structure of bovine trypsin reveals that the trypsin "autolysis loop" is enlarged in kallikrein by two residues but lacks the basic residue at the cleavage site. Substitutions at the calcium-binding site of trypsin which include Arg 70 for Glu 70 possibly interfere with ion binding. Insertions between trypsin residues 95 and 96 obviously form a new kallikrein "autolysis loop" containing the site of cleavage between the A- and B-chains. One carbohydrate moiety is attached to this surface loop at Asn 95, the second to Asn 239 at the same edge of the globular molecule. The residues at the surface of the substrate binding site are substituted to an extent of 85% while the residues forming contacts to the trypsin inhibitor (Kunitz) are highly preserved. Immunodiffusion studies as well as identity of the N-terminal sequences of pancreatic, submandibular and urinary kallikrein reveal the same genetic origin of the three glandular kallikreins.

A comparison of physical and cytogenetic estimates of radiation dose in patients treated with iodine-131 for thyroid carcinoma

Physical and cytogenetic estimates of the whole-body radiation doses have been compared in 11 patients receiving large doses of iodine-131 for the treatment of thyroid carcinoma. The physical estimate was based on the measurement of thyroid uptake, of the plasma activity variation, and of urinary activity. The cytogenetic estimate was obtained from the analysis of chromosome aberrations in peripheral blood lymphocytes. Good agreement between the estimates was observed in patients whose thyroid glands had previously been ablated by radioiodine. In patients who had varying degrees of thyroid function, there were considerable differences between the estimates with the cytogenetic value always being higher. It is suggested that these differences might be due in part to non-uniform irradiation of lymphocytes by local sources of activity in the thyroid and in the liver.

Kinetics of binding of bovine trypsin-killikrein inhibitor (K unitz) in which the reactive-site peptide bond Lys-15--Ala-16 is cleaved, to alpha-chymotrypsin and beta-trypsin

Equilibrium measurements of the binding of reactive-site-cleaved (modified) bovine trypsin-kallikrein inhibitor (Kunitz) to alpha-chymotrypsin and beta-trypsin show a stoichiometric 1:1 association with high binding constants. At least in the case of chymotrypsin much evidence is presented that the reaction with modified inhibitor leads to the same complex as the reaction with virgin inhibitor does. The association rate constant of modified inhibitor with chymotrypsin at pH 7, 22.5 degrees C is 15.8 M-1 S-1. This is about 2 x 10(4) times slower than the binding of virgin inhibitor to that enzyme. In the analogous reaction of modified inhibitor with beta-trypsin, however, the association rate constant (1.2 x 10(4) M-1 s-1 at pH 6.9, 22.5 degrees C) is of about the same order of magnitude as it is in the reaction of virgin inhibitor and trypsin. These and analogous phenomena observed in the reactions of virgin and modified soybean trypsin inhibitor (Kunitz) with alpha-chymotrypsin and beta-trypsin suggest that the specificity of both inhibitors to trypsin is strongly reflected in the association rate constants of the modified forms. The dissociation rate constants of the complexes of trypsin-kallikrein inhibitor with chymotrypsin or with trypsin towards the modified inhibitor are estimated to be unmeasurably slow (half-life times of 45 or 1.5 x 10(4) years, respectively).