A pharmacokinetic approach to the establishment of biopharmaceutic characteristics of different acetylsalicylic acid formulations in man

Eleven acetylsalicylic acid (ASA) formulations were administered to 26 healthy volunteers in a cross-over design. The properties of the preparations differed from conventional, effervescent, buffered to buccal. The objectives of this study were:

• 1 Consideration of the general aspects of a biopharmaceutical study: which parameter for which biopharmaceutic characteristic?
• 2 Measurement of the kinetic parameters of ASA: first-pass effect, mean residence time, mean appearance time, total body clearance, apparent volume of distribution, half-lives, etc.
• 3 Comparison of the formulations.

Most of the formulations yield mean residence times for ASA of 0.3–1.0h, which do not differ significantly (p > 0.05). For most of the products the first-pass effect is about 40 per cent; the average values of the apparent volume of distribution and whole body clearance, corrected for the first-pass effect, are about 201 and 650 ml min^?1, respectively. Peak levels are reached slowly for the buccal formulations, and rapidly for the buffered products. It is difficult, especially for ASA, to characterize the gastro-intestinal absorption with pharmacokinetic model parameters, because the first-pass effect is large and often elimination of ASA is faster than absorption. The model-independent approach has the special advantages of calculating reliable pharmacokinetic parameters, and creating theoretical possibilities to characterize the absorption patterns of the different formulations in a quantitative way. No significant differences in the values of the parameters are found between most of the formulations. The ASA first-pass effect is reasonably constant and buccal application has no advantage. Enteric coating of the outer layer of ASA formulations causes inconsistent absorption and may be categorized under ‘artificial mistakes’.     

Ab initio and PCILO investigations of local anaesthetic-model membrane interactions

A "double zeta" basis set ab initio method was used for investigation of the systems (trimethylamine-dimethylphosphate monoanion)H+, aniline-dimethylphosphate monoanion and formanilide-dimethylphosphate monoanion, which represent the models for associative sites of both local anaesthetics and the phospholipid part of the nerve membrane. According to the authors' calculations, complex I was found to be the most stable with a N+-H...O-hydrogen bond. Further, the PCILO method was used for investigation of the interactions of the polar groups of 1-[2-(2-methoxyphenylcarbamoyloxy)ethyl] piperidine (B) and its cation (BH) with N-methylacetamide, which represents a model of association sites of the lipoprotein part of membrane. The strongest hydrogen bond with the carbonyl group of N-methylacetamide forms a N+-H group of cationic form.     

Quantitation of carcinogen-induced DNA damage and repair in human cells with the UVR ABC excision nuclease from Escherichia coli

Recent studies by others have shown that the endonuclease complexcoded for by the uvrA, uvrB and uvrC genes of Escherichia coli(UVR ABC excision nuclease) can incise DNA containing a varietyof ‘bulky-type’ lesions, such as those resultingfrom u.v. light, (±)-7, 8ß-dihydroxy-9, 10-epoxy-7,8, 9, 10-tetrahydrobenzo[a]pyrene (anti-BPDE), and N-acetoxy-2-acetylaminofluorene.Using partially purified UVR ABC excision nuclease, we havequantitated the number of endonuclease sensitive sites (ESS)in purified DNA isolated from human fibroblasts treated withu.v. light or BPDE. The number of ESS/10⁸ daltons of DNA werecalculated from the number average mol. wt. of the DNA as determinedby sedimentation in alkaline sucrose gradients. The number ofendonuclease sites increased linearly with increasing dosesof either u.v. light or BPDE. The UVR ABC excision nucleasewas able to incise a majority of the BPDE-DNA adducts. Xerodermapigmentosum fibroblasts, complementation group A (XP12BE) had20–25% more ESS at each dose than the BPDE-treated normal(HSBP) cells. Cells treated with 4 µM BPDE and allowed12 h of incubation to perform excision repair showed removalof 60% of the initial number of ESS from HSBP DNA and 40% ofthe ESS from XP-A DNA. Beyond 12 h XP12BE cells lost no additionalESS while HSBP cells continued to lose ESS, athough at a slowerrate, until at 48 h only 22% of the initial ESS remained. Incells treated with 10 J/m² of u.v. light, the UVR ABC excisionnuclease detected 60% of the sites recognized by the pyridiminedimer specific Micrococcus luteus glycosylase/apyrimidinic endonuclease.These results demonstrate the potential use of the UVR ABC excisionnuclease in a quantitative assay for determining the numberof carcinogen-induced lesions in human DNA.     

Chronic lymphocytic leukemia and acquired disorders affecting the immune system: a case-control study

The relationship of a number of subacute or chronic infectious diseases, connective tissue or autoimmune disorders, allergic conditions, and surgical excision of lymphoid tissue with chronic lymphocytic leukemia (CLL) was examined in a case-control study involving 342 cases and 342 matched controls. In both analyses of all matched pairs and those pairs in which both subjects were respondents, no statistically significant association was found between a history of subacute viral infections or subacute and chronic bacterial infections and CLL. Connective tissue or autoimmune disorders also were found not to be associated with CLL. Examination of the association between several allergic conditions and CLL suggested a protective effect as did a "dose-response" analysis, although none of the individual disorders showed a statistically significant relationship; however, a test for linear trend was significant (P = .04). Similarly, examination of the relationship between surgical excision of lymphoid tissue in several anatomic locations and CLL showed a protective effect, statistically significant for tonsillectomy-adenoidectomy (odds ratio = 0.69; 95% confidence interval = 0.48, 0.98). A statistically significant negative dose-response relationship, substantiating the protectiveness of the effect, was found.     

Traumatic atlantooccipital dislocation

A young adult sustained a traumatic atlantooccipital dislocation together with fracture-dislocation at C.4/5 level and had total neurologic deficit below C4 segment. He retained full consciousness but required respiratory support. He developed a stress ulcer with hemorrhage and evidence of "shock lung." He responded to intensive care. Surgery on the 11th day secured reduction and internal fixation at both levels. Death due to respiratory and cardiac arrest followed on the 14th day. Postmortem examination revealed edema of the brain and brainstem.     

Plant Antiviral Agents; VI.1 3-Methoxyflavones as Potent Inhibitors of Viral-Induced Block of Cell Synthesis

An investigation of the constituents responsible for the pronounced antiviral activity observed for extracts of EUPHORBIA GRANTII Oliv. stems has afforded four related 3-methoxyflavones exhibiting remarkable activities against picornaviruses and vesicular stomatitis virus. All compounds were found to be derivatives of 3-methylquercetin. The concentration of 3-methylquercetin (3-MQ) and 3,3'-dimethyl-quercetin (3,3'-DMQ) inhibiting 90 % of polio type 1 and coxsackie B4 viruses in tissue culture was about 0.01 microg/ml, whereas the 50 % cytotoxic concentration was 40 microg/ml. When administered intraperitoneally, 3-MQ protected mice from viremia and lethal infections from coxsac kie B4 virus at a daily dose of 20 mg/kg for a period of nine days. Biochemical studies on the mechanism of action of 3-MQ or 3,3'-DMQ on poliovirus replication suggested that these 3-methoxyflavones are able to protect the host cells from a viral induced shutdown of the cellular protein synthesis. Preliminary structure activity relationship studies have shown the 3-methoxyfunction of the flavones to be essential for the observed antiviral effects.     

Preoperative transhepatic biliary decompression in pancreatic and periampullary cancer

Pancreatic resection for pancreatic and periampullary cancer between 1969 and 1975 at The Ohio State University Hospitals had an associated operative mortality rate of 30% and a morbidity rate of 80%. Transhepatic biliary decompression (THD) has been accepted as a method of preoperative risk reduction in the deeply jaundiced patient and an alternative to surgical biliary decompression. The use of preoperative THD in pancreatic and periampullary cancer was examined. Of 44 patients with bilirubin greater than 10 mg/100 ml, 17 had radical resection (THD=7, no THD=10), and 27 had palliative operation (THD=17, no THD=10). Preoperative serum bilirubin in the THD group was 7.3±1.0 compared to 16.3 ±1.5 in the no THD group (p < 0.05). Operative morbidity rate was: radical surgery: THD (40%), no THD (70%); palliative surgery: THD (18%), no THD (20%). Operative mortality rate was: radical surgery: THD (28%), no THD (60%); palliative surgery: THD (6%), no THD (0%). Catheter-related complications were minimal. Preoperative THD tends to reduce the risk of curative resection for pancreatic and periampullary cancer, but does not alter the outcome of palliative surgery. Long-term THD may be an alternative if palliative surgical biliary decompression either fails or is not technically possible in the patient with unresectable cancer.

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Resumen Se ha agudizado el debate relativo al papel de la resección curativa en el tratamiento del carcinoma pancreático y periampular. Mucha de la discusión se deriva de la excesiva morbilidad y mortalidad de la pancreatoduodenectomía y de la pancreatectomía total. Las cifras sobrepasan el porcentaje de supervivencia a 5 anos en todas las series mayores, y en algunos reportes la mortalidad operatoria es igual o mayor que el porcentaje de pacientes que sobreviven un año.La resección pancreática para cáncer pancreático y periampular entre los años 1969 y 1975 en los Hospitales de la Universidad del Estado de Ohio estuvo asociada con una mortalidad de 30% y una morbilidad de 80%. La descompresión biliar transhepática (DBT) ha sido aceptada como un método de reducción preoperatoria del riesgo quirúrgico en los pacientes intensamente ictéricos y como una alternativa a la descompresión biliar quirúrgica. El uso de la DBT preoperatoria en el cancer pancreático y periampular fué analizado. De 44 pacientes con bilirrubina mayor de 10 mg/100 ml, 17 fueron sometidos a resección radical (DBT = 7, no DBT = 10), y 27 tuvieron una operación paliativa (DBT = 17, no DBT = 10). La bilirrubina sérica en el grupo con DBT fué de 7.3±1.0, comparada con 16.3±1.5 en el grupo sin DBT (p < 0.05). La siguiente fué la morbilidad operatoria: cirugía radical: DBT 40%, no DBT 70%; cirugía paliativa: DBT 18%, no DBT 20%. La siguiente fué la mortalidad operatoria: cirugía radical: DPT 28%, no DPT 60%; cirugía paliativa: DBT 6%, no DBT 0. La DBT preoperatoria tiende a reducir el riesgo de la resección curativa para cáncer pancreático y periampular, pero no modiflca el resultado de la cirugía paliativa. La DBT prolongada puede ser una alternativa si la descompresión biliar quirúrgica falla o no es técnicamente posible en el paciente con cáncer no resecable.

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Résumé La résection pancréatique pour cancer périampullaire ou pour cancer du pancréas entre 1969 et 1975 à Ohio State University Hospital accuse une mortalité opératoire de 30% et une morbidité de 80%. Le drainage biliaire transhépatique (transhepatic biliary decompression: T.H.D.), en présence de ces résultats, a été employé à titre pré-opératoire pour diminuer les risques de l'intervention chez les malades très ictériques et comme alternative au drainage biliaire chirurgical.Chez 44 malades qui présentaient un taux de bilirubine supérieur à 10 mg/dl, 17 ont subi une exérèse (7 après drainage transhépatique, 10 sans drainage transhépatique), 27 ont été traités par une intervention palliative (17 après drainage, 10 sans drainage). Le taux de bilirubine pré-opératoire fut ramené à 7.3±10 chez les malades drainés alors qu'il atteignait 16.3± 1.5 chez les malades qui n'avaient pas subi de drainage préalable.La morbidité opératoire fut en cas de chirurgie radicale de 40% après drainage et de 70% en l'absence de drainage; en cas de chirurgie palliative elle fut de 18% après drainage et de 20% en l'absence de drainage. La mortalité opératoire fut en cas de chirurgie radicale de 28% après drainage et de 60% en l'absence de drainage; en cas de chirurgie palliative elle fut de 6% après drainage et de 0% en l'absence de drainage. Les complications du drainage sont très rares. En un mot le drainage biliaire pré-opératoire réduit les risques de l'exérèse des cancers pancréatiques et des cancers périampullaire mais elle est sans influence en cas d'intervention palliative. Le drainage biliaire transhépatique prolongé offre une alternative au drainage chirurgical lorsque celui-ci échoue ou quand le cancer ne peut être réséqué.

     

Cervical spine injuries in rugby players.

Nine patients with serious cervical spine injuries that occurred while they were playing rugby were seen in a British Columbia acute spinal cord injury unit during the period 1975-82. All the injuries had occurred during the "scrum" or the "tackle". Two of the patients were rendered permanently quadriplegic, and one patient died. There is a need for a central registry that would record all cervical spine injuries in rugby players as well as for changes in the rules of the game.     

Ciliary process microvasculature of the primate eye

Using methylmethacrylate microvascular luminal castings, we studied the three-dimensional angioarchitecture of the primate ciliary process with the scanning electron microscope. We found that the ciliary processes are served by vessels that radiate anteriorly and posteriorly from the "major arterial circle" of the iris. The anterior arterioles possess focal constrictions and supply the anterior and marginal aspects of the major ciliary processes as well as interprocess networks that connect contiguous processes. The posterior arterioles lack focal constrictions and supply the minor ciliary processes via posterior interprocess networks. Major and minor ciliary process capillaries are irregularly dilated and pass posteriorly to drain into the choroidal veins. Finally, venous arcades exist which directly connect anterior and posterior interprocess networks with the choroidal veins and thus bypass the ciliary processes entirely. The presence of focal constrictions in the anterior arterioles suggests a site for possible autonomic or neurohumoral control of blood flow into the major ciliary processes.