Determination of rate order for degradation of drugs with nonisothermal stability experiment

The inability of ordinary nonisothermal experiments to determine the rate order (n) of drug degradation is discussed on the basis of a theoretical study of simulated nonisothermal data. In ordinary nonisothermal experiments, using either r or sigma(C[experiment] C[compute])2 as the measure of goodness of fit, the rate order cannot be assessed because the same set of c-t data can be well fitted by different combinations of estimates for n and the activation energy (E). Hence, a new nonisothermal heating-and-cooling model is introduced as a revision, in which sigma(C[experiment] C[compute])2 changes significantly with various kinetic models. Therefore, all the kinetic parameters, including the rate order, can be obtained in one nonisothermal stability experiment. Furthermore, the ability to determine rate order is significantly affected by the extent of drug degradation and experimental error, though not by sampling frequency or temperature change. To demonstrate the applicability of the heating-and-cooling model, the stability and rate order of degradation of vitamin C tablets was studied by this method.

In vitro metabolism of simvastatin in humans [SBT]identification of metabolizing enzymes and effect of the drug on hepatic P450s

Simvastatin (SV) is a lactone prodrug used for the treatment of hypercholesterolemia. Upon incubation of SV with liver microsomal preparations from human donors, four major metabolic products were formed (3'-hydroxy SV, 6'-exomethylene SV, 3',5'-dihydrodiol SV, and the active hydroxy acid, SVA), together with several minor unidentified metabolites. The 3',5'-dihydrodiol SV, a new metabolite, was inactive as an inhibitor of HMG-CoA reductase. Kinetic studies of SV metabolism in human liver microsomes suggested that the major NADPH-dependent metabolites (3'-hydroxy SV, 6'-exomethylene SV, and 3',5'-dihydrodiol SV) were formed with relatively high intrinsic clearances, consistent with the extensive metabolism of SV observed in vivo. Based on four different in vitro approaches, namely 1) correlation analysis, 2) chemical inhibition, 3) immunoinhibition, and 4) metabolism by recombinant human P450, it is concluded that CYP3A is the major enzyme subfamily responsible for the metabolism of SV by human liver microsomes. Both CYP3A4 and CYP3A5 were capable of catalyzing the formation of 3',5'-dihydrodiol, 3'-hydroxy, and 6'-exomethylene metabolites. However, CYP3A4 exhibited higher affinity (> 3 fold) for SV than CYP3A5. Also, the studies indicated that CYP2D6, CYP2A6, CYP2C8, CYP2C9, CYP2C19, CYP1A2, and CYP2E1 did not play significant roles in the metabolism of SV in vitro. Over the concentration range of 0-40 microM, SV inhibited the activity of CYP3A, but not the activities of CYP2C8/9, CYP2C19, or CYP2D6 in human liver microsomes. The inhibition of hepatic midazolam 1'-hydroxylase, a CYP3A marker activity, by SV was competitive with a Ki value of approximately 10 microM. SV was > 30-fold less potent than ketoconazole and itraconazole as an inhibitor of CYP3A. Under the same conditions, SVA, the hydrophilic hydroxy acid form of SV, did not inhibit CYP3A, CYP2C8/9, CYP2C19, or CYP2D6 activities. The results suggested that the in vivo inhibitory effects of SV on the metabolism of CYP3A substrates likely would be less than those of ketoconazole and itraconazole at their respective therapeutic concentrations. In addition, metabolic activities mediated by the other P450 enzymes tested are unlikely to be affected by SV.

Bronchial tuberculosis. Cytologic diagnosis of fiberoptic bronchoscopic brushings

OBJECTIVE

To determine the cytomorphologic features of bronchial tuberculosis on fiberoptic bronchoscopic brushings and its diagnostic value.

STUDY DESIGN

Seven hundred forty-six bronchoscopic examinations were retrospectively studied. The patients' macroscopic findings made by fiberoptic bronchoscopic examination, as well as brush cytologic and biopsy findings, were reviewed.

RESULTS

Of 746 bronchoscopic brushing specimens, 23 were diagnosed as endobronchial tuberculosis by cytomorphology; that accounted for about 3.1% of cases. The same or a similar diagnosis was made for both specimen types in 16 of the specimen pairs. Acid-fast stain showed that only one brushing was positive (4.3%); all the biopsy specimens were negative. Epithelioid cell granulomas and/or caseous necrosis were found in 23 cases of brush smears, while tuberculous granulomas accounted for 16 bronchial biopsies. Seven were nonspecific chronic bronchitis or normal bronchial mucosa.

CONCLUSION

The cytomorphologic alterations of tuberculosis are suitable for diagnosing bronchial tuberculosis on fiberoptic bronchoscopic brushings. Its sensitivity for defining bronchial tuberculosis is not lower than that of bronchial histologic biopsies or bacteriologic examination.

[Treatment of malignant or aggressive bone tumors with microwave induced hyperthermia]

Limb-sparing procedures have been well established for dealing with malignant bone tumors. Unfortunately, these procedures have different problems. We used an alternative operation combined with microwave-induced hyperthemia to modify the surgical methods. Thermotherapy with microwave intracorporeal irradiation was used to treat 112 patients with bone tumors. In this series, 79 had malignant tumors and 33 aggressive benigh tumors. Postoperatively, immune therapy was carried out regularly. The patients immunologic functions were monitored by assay of the subpopulation of T cells, IL-2 and sIL-2R (soluble IL-2 receptor). Follow-up varied from 3 to 50 months (mean 23 month) s. Excluding 5 patients with malignancy in the vertebrae treated for palliation, 107 were evaluated by oncological and orthopedic criteria. 10 patients had local recurrence and required amputation. The remaining 97 had excellent local control. In 12 of the 74 patients with malignancy of the extremities, lung metastasis occurred 4 months to 2 years after surgery. Pathological fracture occurred at devitalized bone in 8 patients. In 29 out of 40 tumor-free cases followed for more than 2 years, the knee joints functioned properly with almost full range of motion. Single photon emission computered tomography (SPECT) study revealed revascularization of the devitalized tumor bearing bone segment could accomplish in one year or more. The immune state was improved after thermotherapy plus immunotherapy in the majority of patients. These results indicated that the use of microwave hyperthermia and adjuvant immunotherapy in the surgical treatment of bone tumors can be considered a definitive procedure, which is safe and well-tolerated.

New spirostanol glycosides from Anemarrhena asphodeloides

Two new spirostanol saponins, named anemarsaponin F (2b) and G (4b), along with six known spirostanol saponins were obtained from the rhizomes of Anemarrhena asphodeloides Bunge. On the basis of spectral analyses and chemical evidence, the structures of 2b and 4b were established as neogitogenin 3-O-beta-glucopyranosyl-(1-->2) [beta-xylopyranosyl-(1-->3)]-beta-glucopyranosyl (1-->4)-beta-galactopyranoside) and lilagenin 3-O-beta-glucopyranosyl-(1-->2)-[beta-xylopyranosyl-(1-->3)]-beta- glucopyranosyl-(1-->4)-beta-galactopyranoside, respectively.

Exponential heating in drug stability experiment and statistical evaluation of nonisothermal and isothermal prediction

A new nonisothermal heating model (exponential heating model) for drug stability experiments, based on a theoretical study of simulated nonisothermal data, is presented. In the model, the heating rate dT/dt is increased by 2-4 times at every increase of 10 degrees C in temperature: dT/dt = a(T-T0)/10.(dT/dt)0 where a is the times by which the heating rate is increased at every increase of 10 degrees C. A computation method with optimization and Simpson integration for the experiment was also introduced. The estimates for the shelf-life and activation energy obtained by the exponential and other nonisothermal heating models were statistically evaluated and were compared with those obtained by the isothermal method under various conditions. The results indicated that under the same experimental conditions, the estimates obtained by the exponential heating model were significantly more accurate and precise than those obtained by the linear, reciprocal, and logarithmic heating models. The accuracy and precision of the estimates were independent of the shelf-life of drugs and experimental period. The estimates obtained by the isothermal method were somewhat more accurate and precise than those obtained by the exponential heating model. However, the experimental period needed by the isothermal method was about five times longer than that needed by the exponential heating model. The results also showed that in each of the heating models, the estimates are more accurate and precise by increasing the extent of drug degradation, changing temperature range or sampling frequency, or by having the mean temperature closer to room temperature. To demonstrate its applicability, the exponential heating model was used to study the stability of vitamin C tablets and predict their shelf-life.

Muscle coordination of maximum-speed pedaling

A simulation based on a forward dynamical musculoskeletal model was computed from an optimal control algorithm to understand uni- and bi-articular muscle coordination of maximum-speed startup pedaling. The muscle excitations, pedal reaction forces, and crank and pedal kinematics of the simulation agreed with measurements from subjects. Over the crank cycle, uniarticular hip and knee extensor muscles provide 55% of the propulsive energy, even though 27% of the amount they produce in the downstroke is absorbed in the upstroke. Only 44% of the energy produced by these muscles during downstroke is delivered to the crank directly. The other 56% is delivered to the limb segments, and then transferred to the crank by the ankle plantarflexors. The plantarflexors, especially soleus, also prevent knee hyperextension, by slowing the knee extension being produced during downstroke by the other muscles, including hamstrings. Hamstrings and rectus femoris make smooth pedaling possible by propelling the crank through the stroke transitions. Other simulations showed that pedaling can be performed well by partitioning all the muscles in a leg into two pairs of phase-controlled alternating functional groups, with each group also alternating with its contralateral counterpart. In this scheme, the uniarticular hip/knee extensor muscles (one group) are excited during downstroke, and the uniarticular hip/knee flexor muscles (the alternating group) during upstroke. The ankle dorsiflexor and rectus femoris muscles (one group of the other pair) are excited near the transition from upstroke to downstroke, and the ankle plantarflexors and hamstrings muscles (the alternating group) during the downstroke to upstroke transition. We conclude that these alternating functional muscle groups might represent a centrally generated primitive for not only pedaling but also other locomotor tasks as well.

Novel saponins hainaneosides A and B isolated from Marsdenia hainanensis

Novel saponins possessing fertility-regulating activity, hainaneosides A (1) and B (2), have been isolated from the twigs and stems of Marsdenia hainanensis, and their structures have been elucidated unambiguously as 12-nicotinoyl sarcostin-3-O-beta-D-glucopyranosyl-(1-->4)-3-O-methyl-6-deoxy-bet a-D- allopyranosyl-(1-->4)-beta-D-oleandropyranosyl-(1-->4)-beta-D- cymaropyranosyl-(1-->4)-beta-D-cymaropyranoside and 12-nicotinoyl-20-cinnamoyl sarcostin-3-O-beta-D-glucopyranosyl-(1-->4)-3-O-methyl-6-deoxy-bet a-D- allopyranosyl-(1-->4)-beta-D-oleandropyranosyl-(1-->4)-beta-D-c ymaropyranoside using NMR spectroscopic techniques and chemical transformations.

Cloning and characterization of SNAP50, a subunit of the snRNA-activating protein complex SNAPc

The human RNA polymerase II and III snRNA promoters share a common basal element, the proximal sequence element (PSE), which is recognized by a complex we refer to as the snRNA-activating protein complex (SNAPc). Biochemical purifications suggest that SNAPc is composed of at least four polypeptides of 43, 45, 50 and 190 kDa, as well as variable amounts of the TATA box binding protein, TBP. cDNAs encoding the 43 and 45 kDa subunits, SNAP43 and SNAP45, have been isolated, but there is no evidence that either of these subunits contacts DNA. Here we report the isolation of cDNAs encoding the 50 kDa subunit of SNAPc, SNAP50. The open reading frame predicts a 411 amino acid protein, which contains two potential zinc finger motifs. Depletions with anti-SNAP50 antibodies inhibit RNA polymerase II and III snRNA gene transcription in vitro. SNAP50 interacts with SNAP43 in co-immunoprecipitation experiments, but not with SNAP45 or TBP. UV cross-linking experiments suggest that SNAP50 contacts DNA in the SNAP complex. These results are consistent with the same core SNAP complex recognizing the PSEs of RNA polymerase II and III snRNA promoters, and provide an initial view of the architecture of the SNAP complex.

Surgical treatment of bone tumors in conjunction with microwave-induced hyperthermia and adjuvant immunotherapy. A preliminary report

OBJECTIVE

To develop an alternative approach in conjunction with microwave-induced hyperthermia.

PATIENTS AND METHODS

Thermotherapy with microwave intracorporeal irradiation was used to treat 73 patients with bone tumors. The series was composed of 58 patients with malignant tumors and 15 with benign tumors: most of tumors occurred about knee joints (53/73 = 72.6%). The surgical procedure included separating the tumor bearing segment from surrounding normal tissues with a safe margin, cooling the normal tissues including the neurovascular bundle and the intraarticular structures with a water circulation system, while heating the tumor with the antenna array of a microwave system and providing an adequate soft-tissue cover for the dead bone. Postoperatively, an immune therapy regimen was carried out regularly. The patients' immunologic functions were monitored by assay of the subpopulation of T cells, IL-2 and sIL-2 R (soluble IL-2 receptor).

RESULTS

Follow-up varied from 3 to 38 months (mean 19 months). Excluding 3 patients with malignancy in the vertebrae treated for palliation, 70 were evaluated according to oncological and orthopedic criteria. Five patients had local recurrence and required amputation. The remaining 65 had excellent local control. In 6 of the 55 patients with malignancy of the extremities, lung metastasis occurred one to two years after surgery. The oncological results were similar to those obtained by other limb-saving procedures. Pathological fracture occurred at devitalized bone in 5 patients. In 72.5% of the patients (29 of 40 tumor-free cases followed more than one year), knee joints functioned well, being stable and painless with almost full range of motion. Single photon emission computered tomography (SPECT) for 16 patients revealed revascularization of the devitalized tumor bearing bone segment could accomplish in one year or more. The immune states were improved in various extends after thermotherapy plus immunotherapy in the majority of patients.

CONCLUSION

These results show that the use of microwave hyperthermia and adjuvant immunotherapy in conjunction with the surgical treatment of bone tumors can be considered a definitive procedure, which is safe and well-tolerated. The oncological and orthopedic results are encouraging.

Ingenane diterpenes from Euphorbia petiolata

From the whole plants of Euphorbia petiolata, four new ingenane-type diterpenoids, 3,20-O-diacetylingenol 5-O-(2' E,4' Z)-tetradecadienoate (1), 5,20-O-diacetylingenol 3- O-(2' E,4' Z)-tetradecadienoate (2), ingenol 3-O-(2' E,4' Z)-tetradecadienoate (3), and 5,20-O-isopropylidenylingenol 3-O-(2' E,4' Z)-tetradecadienoate (4) were isolated. Their structures were elucidated by spectroscopic methods and chemical transformations.

[Assay of contents of lysozyme, SIgA, IgA and IgG in tongue coating]

The contents of lysozyme, SIgA, IgA, and IgG in 98 cases with pathological tongue coating and 30 cases of normal coating were analysed by using the thorough random analysis of variance. The results showed that the content of lysozyme in pathological coating was lower than that in normals significantly (P < 0.0001), while the contents of SIgA, IgG in pathological coating were higher than that of normals (P < 0.0001). It indicates that immune reaction is very active during the development of pathological tongue coating.

[Variolation, pioneer of modern immunology]

Smallpox spread into China at the end of the Han Dynasty. Therapeutic remedies were first recorded in Ge Hong's Zhou Hou Jiu Zu Fang in the Jin Dynasty. It is possible that variolation made its first appearance in the Northern Song Dynasty. It can be sure that there was a variolation centre in Taiping County of Ningguo District in Anhui. The Kangxi Emperor of the Qing Dynasty advocated and encouraged the popularization of the art which was then spread outside China. Edward Jenner, the English physician who practised variolation, modified variolation into vaccination, which eventually lead to the formation of modern immunology and the declaration of eradication of smallpox on the Earth by WHO in 1980. The article describes the historical process of variolation to vaccination and points out that the modified variolation was safe and reliable. Unfortunately, the westerners only followed the simple smallpox-juice method which was relatively more dangerous.

[A study on the degradation kinetics of nicotinamide powder]

The effect of temperature and humidity on the degradation of nicotinamide powder was studied below the critical relative humidity at temperatures 50-80 degrees C and relative humidities 50-80%. The rate equation of the degradation of nicotinamide under isothermal and constant humidity conditions is -dC/dt=k(Co-C)-1, where k is the apparent rate constant of degradation, Co and C are initial concentration and concentration at time t of nicotinamide, respectively. The relationship between the apparent rate constant of degradation and relative humidity RH is in K=a + m (RH), where a and m are constants. When RH are 50.35, 66.85, 75.33 and 80.35%, the apparent activation energies of degradation from Arrhenius equation are 219.94, 181.86, 168.99 and 153.89 kJ/mol, respectively. The rate equation the photodegradation of nicotinamide under room temperature is -dR/dt=K' (Ro-R)-1, where K' is the apparent rate constant of photodegradation, Ro and R are initial reflectance and reflectance at time t of nicotinamide, respectively.

[Chemical constituents of Actinidia kolomikta (Rupr. et Maxim.) Planch]

Two crystalline components I and II were isolated from the roots of Actinidia kolomikta. I was identified as delta 7-stigmasterol and II was named alpha-kolomiktriose and elucidated as 2, 3-di-0-beta-D-galactopyranosyl-alpha-D-galactopyranose on the basis of spectral data (13C NMR, 1H NMR, IR and EI-MS).

Serodiagnosis of Lyme borreliosis by western immunoblot: reactivity of various significant antibodies against Borrelia burgdorferi

The significance of various antibodies against Borrelia burgdorferi was studied by Western blot (immunoblot) by using 578 human serum samples. The proteins regularly detected by using samples from patients with Lyme borreliosis were those with bands with molecular masses of 94, 83, 75, 66, 60, 55, 46, 41, 39, 34, 31, 29, 22, and 17 kDa. The detectable frequencies of most of these proteins appeared to be significantly different between the sera from patients with Lyme borreliosis and those from normal control individuals as well as from the group with syphilis. The 39-kDa protein band recognized by polyvalent antibody was found to be the most significant marker for Lyme borreliosis. Furthermore, an anti-39-kDa immunoglobulin M response was detected in the samples from patients with early-stage Lyme borreliosis. Results from the use of monoclonal antibodies and patient sera revealed that the 39- and 41-kDa proteins may be structurally related but are immunologically distinct antigens. The significance of antibody reactivities to the 41-, 94-, 22-, 31-, and 34-kDa protein bands is also discussed.

Trends in basal cell carcinoma, squamous cell carcinoma, and melanoma of the skin from 1973 through 1987

Major increases have occurred in the incidence of basal cell carcinoma and squamous cell carcinoma of the skin, as well as in cutaneous malignant melanoma during the period 1973 through 1987 in British Columbia. The greatest increases in basal and squamous cell carcinomas are on the head and neck. This indicates that exposure to sunlight is the major causative factor. The greatest increase in melanoma is on the trunk in men and on the lower limbs in women. The dramatic increases in nonmelanoma skin cancers in British Columbia, a relatively low sunlight area, suggest that major prevention programs are needed in areas that are not considered "sunspots."

Automated, fully computerized analysis of the clinical electroretinogram

Being a relatively simply composed bioelectric signal, the ERG lends itself very well to computer analysis. This paper presents the results obtained by the employment of an automated, fully computerized ERG analysis system. It is concluded that programmable computing facilities have the effect of rendering diagnostic ERG evaluation more accurate and reliable as well as saving a lot of human effort.